Growing Seedlings

Faster Harvest

The seedling method allows you to obtain mature heads 2–4 weeks earlier than direct sowing in open ground (Nonnecke, 1989). By transplanting already formed plants with 4–6 true leaves, you give them a head start over weeds and create conditions for faster development. Early‑maturing cabbage varieties grown through seedlings can yield a harvest as early as early July, whereas direct sowing shifts the harvest to late July – August (Ториков и Сычев, 2018).

Controlled Development

Growing seedlings in controlled conditions allows you to manage key growth factors: temperature, light, and humidity. This is especially important for cabbage, which is sensitive to temperature fluctuations at a young age. You gain the ability to:

• Create optimal conditions for seed germination when it is still too cold outdoors for sowing.
• Provide plants with the necessary amount of light, preventing them from stretching.
• Precisely regulate humidity and avoid overwatering, which triggers fungal diseases (Starczev, 2021).

Protection in Early Stages

Young cabbage seedlings are a favourite food for flea beetles, cabbage flies, and other pests (Аутко и др., 2012). In protected cultivation, seedlings are safely sheltered from these threats. Moreover, you can carry out targeted seed and young plant treatments for disease prevention, something that cannot be done in field conditions. Once seedlings are stronger and transplanted, they can better withstand pests.

More Efficient Use of the Season

The seedling method makes the most of a short growing season, especially in regions with cool climates or risky farming zones. You gain the ability to grow late‑maturing varieties with a long vegetation period that would simply not ripen before cold weather if sown directly (Welbaum, 2015). In addition, seedlings allow for denser planting and early marketable production.

Climatic Conditions and Soil Temperature

White cabbage seeds begin to germinate at soil temperatures of +5…+6 °C, but uniform, vigorous emergence occurs only when the upper layer (at sowing depth 2–2.5 cm) warms to +8…+10 °C (Аутко и др., 2012; Iowa State University Extension, 2024). If sown earlier, seeds may remain in cold soil for a long time, rot, or produce sparse seedlings. In central Russia, this warming usually occurs in the second–third decade of April – first decade of May (Аутко и др., 2012; Ториков и Сычев, 2018). In more northern regions, the dates shift to late May, while in the south (e.g., the steppe zone), sowing is possible as early as late March – early April.

Important: Young cabbage seedlings tolerate short‑term frosts down to –2…–3 °C, and established plants – down to –5…–7 °C (Welbaum, 2015; Ториков и Сычев, 2018). However, if prolonged cold (below +5 °C) occurs after sowing, development slows down, and plants may switch to the generative phase (bolting) in the first year, making the harvest unsuitable for storage.

Frost‑Free Period Length and Maturity Group

Direct sowing is worthwhile only if plants have enough time to fully form a head before autumn frosts. To achieve this, you must select the right variety:

Source: (Аутко и др., 2012; Старцев, 2021; Ториков и Сычев, 2018).

In regions with short summers (northern Non‑Black Earth, Ural, Siberia), even early varieties often fail to form dense heads before cold weather when sown directly, so the seedling method is preferable there (Nonnecke, 1989).

Advantages of Direct Sowing

1. More powerful root system. Plants grown from seeds in the ground develop a taproot that can reach 1.5–2 m deep, making them more drought‑tolerant (Welbaum, 2015; Старцев, 2021).

2. Labour and cost savings. You do not spend time and money on growing seedlings, buying pots, substrate, or additional lighting.

3. Reduced transplant shock. Plants do not suffer the stress of pricking out and transplanting; their growth is uninterrupted.

4. Possible earlier harvest by 10–15 days compared to seedling culture, provided early spring sowing (Ториков и Сычев, 2018) – this seems paradoxical but is explained by the root system adapting faster to soil conditions.

Disadvantages of Direct Sowing

1. Weather dependence. Late frosts, drought, or prolonged rains can destroy seedlings or severely delay development.

2. Higher seed consumption. You must sow with a reserve and then thin out, and hybrid seeds are expensive.

3. Vulnerability to pests. Seedlings in the field are more accessible to flea beetles, cabbage flies, and slugs. You have to use insecticides or cover materials more frequently (Iowa State University Extension, 2024; University of Minnesota Extension, 2024).

4. Later maturation compared to seedlings (except for the early‑sowing case). Typically, direct sowing delays marketable head production by 2–3 weeks (Nonnecke, 1989).

When Is Direct Sowing Justified?

Direct sowing in open ground is recommended:

• In regions with mild winters and a long warm season (southern Russia, Central Asia, Mediterranean, southern US states), where you can sow before winter or very early in spring (Welbaum, 2015; Nonnecke, 1989).
• For mid‑season and late‑maturing varieties in areas with a long frost‑free period (>150 days).
• For early‑maturing varieties in the central zone when using temporary plastic covers or agrofibre, which protect seedlings from return cold and accelerate soil warming (Аутко и др., 2012).
• In home gardening, if you want produce for summer consumption without the extra hassle of seedlings, but are willing to risk some crop loss due to weather.

Recommendation: If your growing season is less than 120 days, it is better to use the seedling method even for early varieties – this guarantees a stable harvest. When sowing directly, be sure to provide frost protection, systematic watering, and treatments against flea beetles (Iowa State University Extension, 2024; Oklahoma State University Extension, 2024).

In the next chapter, we will help you make a final decision by comparing both methods in specific situations.

What Factors Influence the Choice?

Comparative Table of Methods

Selection Table by Climate and Purpose

Use this table to determine the best method for your situation.

Recommendations for Different Situations

• For a home gardener with a small plot in a moderate climate – choose seedlings for early varieties and all late varieties. This guarantees a harvest and extends the consumption season.
• For a farmer growing cabbage for sale – combine both methods: seedlings for the earliest produce, direct sowing for the bulk of mid‑season varieties. This reduces costs and spreads the workload for harvesting (Ториков и Сычев, 2018; Nonnecke, 1989).
• For regions with mild winters (south) and large areas – direct sowing is economically more profitable, especially with precision seeders and irrigation.
• For organic farming – seedlings are preferable, as they allow reduced pesticide use at early stages (Iowa State, 2024).

Brief Summary

Seedlings give control, early harvest, and reliability – choose them in cool climates and for late varieties. Direct sowing saves labour and produces drought‑tolerant plants – it is good in warm regions and for mid‑season varieties. In most cases, you can combine both methods to optimise production and reduce risks.

In the next chapter, we will discuss in detail sowing dates for seedlings – how to calculate them correctly for your region and specific varieties.

Main Reference: Last Spring Frost Date

All cabbage seedling sowing dates are calculated from the date of the last spring frost in your region. This is the starting point that you need to determine for your site.

Average date of the last frost is an approximate date after which the probability of night frosts becomes minimal. It varies greatly by region:

• Southern Russia, Black Earth region, Mediterranean: late March – early April.
• Central Russia, northeastern US, Central Europe: late April – first decade of May.
• Northern regions (Ural, Siberia, Scandinavia, Canada): late May – early June.

You can refine the last frost date from local agrometeorological reference books or from long‑term observations. Many gardeners use a "safe" date when the frost probability drops below 10% (Nonnecke, 1989; Ториков и Сычев, 2018).

Sowing Dates by Maturity Group

White cabbage is divided into maturity groups, and each has recommended sowing and transplanting dates.

Sources: (Аутко и др., 2012; Старцев, 2021; Ториков и Сычев, 2018; Nonnecke, 1989).

Explanation: Early cabbage is grown with a longer seedling period because early in the season the day length is shorter and temperatures are lower, slowing development. Late varieties, on the other hand, grow faster in warm, long‑day conditions, so 30–40 days are sufficient for good seedling formation.

How to Adapt Dates to Your Specific Region

To apply these recommendations to your site, follow this algorithm:

1. Determine the average date of the last frost in your area.

2. Select the maturity group of the variety you plan to grow.

3. Subtract the seedling age (in days) from the transplanting date – you get the approximate sowing date.

4. Adjust based on current year's weather:

• If spring is cold and protracted, it is better to delay sowing slightly or provide additional lighting.
• If spring is early and warm, you can sow 5–7 days earlier, but only if you have the ability to transplant at the optimal time.

Example for southern regions (last frost ~1 April):

• Early varieties: sowing 5–10 February (in heated greenhouses) or 20–25 February (in heated hotbeds), transplanting in late March – early April.
• Late varieties: sowing 15–25 March, transplanting 25 April – 5 May.

Example for northern regions (last frost ~5 June):

• Early varieties: sowing 10–15 April, transplanting 25 May – 1 June.
• Late varieties: sowing 20–30 April, transplanting 1–10 June.

Special Cases: Very Early and Winter Sowings

• Ultra‑early varieties (65–80 days) are sometimes sown for seedlings as early as February–March to get the first harvest in June. But this requires heated greenhouses and mandatory supplementary lighting (Аутко и др., 2012).
• Winter sowing of seeds in the ground (late October – November) is practised in warm regions to obtain early spring seedlings. In moderate climates, this method is risky due to unstable winters and is rarely used (Nonnecke, 1989).

General Rules and Warnings

1. Do not rush with early varieties – overly early seedlings stretch, become brittle, establish poorly after transplanting, and under prolonged cold may bolt (Nonnecke, 1989; Oklahoma State, 2024).

2. Do not be late with late varieties – if sown too late, seedlings will not gain enough mass, and heads will not mature before frost.

3. Consider the growing system – if you grow seedlings in cell trays with limited root volume, the age at transplanting may be slightly less than when grown in pots (Welbaum, 2015).

4. Always account for weather anomalies – climate has become unstable in recent years, so monitor forecasts and be ready to adjust dates.

Practical Advice

Keep a gardener's diary and record sowing dates, transplanting dates, emergence, and harvest dates for each variety. After 2–3 years, you will have your own optimal dates for your site – they will always be more accurate than any tables. (Iowa State University Extension, 2024)

In the next chapter, we will discuss how to properly prepare seeds for sowing – from calibration to germination stimulation.

Calibration (Size Sorting)

Why it is needed. Cabbage seeds within a batch vary in size and weight. Large seeds produce more vigorous seedlings, while small ones produce weaker plants. If you sow a mixture, plants will develop unevenly: some will outgrow others, and by transplanting time the seedlings will be of different sizes, complicating care and harvesting (Welbaum, 2015). Calibration allows you to select seeds of approximately uniform size, ensuring uniform emergence and even seedlings.

How to do it. At home, the simplest way is to use sieves with different mesh sizes or simply visually discard very small, shrivelled, and damaged seeds. For more accurate sorting, you can use a 3–5% sodium chloride solution: drop seeds into the solution, stir, let settle for 2–3 minutes, then remove the floating (non‑viable) ones, wash the settled seeds in clean water, and dry (Nonnecke, 1989). However, after salt treatment, seeds must be dried to a free‑flowing state, otherwise they may rot during sowing.

Important: For precise sowing (especially in cell trays), calibration is essential because it allows you to dose seeds and avoid extra thinning. Professional seed producers often sell already calibrated seeds, but if you use your own or uncalibrated purchased seeds, sorting should be done yourself.

Disinfection (Seed Treatment)

Why it is needed. Cabbage seeds may be infected with fungal and bacterial pathogens internally (e.g., vascular bacteriosis Xanthomonas campestris, phomosis Phoma lingam, alternariosis Alternaria brassicae) or on the surface. If disinfection is not done, these infections will manifest on seedlings, can kill the seedlings, or weaken plants, affecting the yield (Аутко и др., 2012; Nonnecke, 1989; Oklahoma State, 2024).

Main disinfection methods:

1. Hot water treatment. Place seeds in water at 48–50 °C for 20 minutes (for white cabbage, broccoli, and cauliflower) or 25 minutes for cabbage (Oklahoma State, 2024). Then quickly cool in cold water (2–3 minutes) and dry to free‑flowing consistency (Аутко и др., 2012). This method is effective against bacterial diseases and some fungal diseases, but may reduce germination of old or weak seeds, so it is recommended only for fresh, high‑quality seeds.

2. Chemical seed treatment. Treat seeds with fungicide products approved for home gardening (e.g., TMTD, Fundazol, Prestige). On an industrial scale, pelleting or encrustation – coating seeds with a layer containing fungicide and stimulants – is used (Аутко и др., 2012). For the home gardener, the simplest approach is to buy already treated seeds (they are usually brightly coloured) – this is the most reliable and safe method, especially if you are unsure of seed health.

3. Biological agents. Recently, biopreparations based on beneficial microorganisms (e.g., Fitosporin, Trichodermin) have become more common; they suppress pathogens without harming the environment. They are less aggressive, but their effectiveness is lower than chemical agents, especially against severe infections (Аутко и др., 2012). For organic farming, this is a good choice.

Important: After chemical treatment, seeds must be thoroughly dried and stored separately from food products. Handle fungicides with gloves and follow safety precautions.

Soaking and Germination Stimulation

Why it is needed. Cabbage seeds have a dense coat that slows water uptake. Soaking accelerates imbibition and triggers biochemical processes of germination, shortening emergence time by 2–3 days (Welbaum, 2015; University of Minnesota, 2024). Growth stimulants further enhance germination vigour and young plant stress tolerance.

How to soak. Place seeds in warm water (about +20 °C) for 12–24 hours. Change the water 1–2 times to prevent stagnation. After soaking, lightly dry seeds to a free‑flowing state (so they don't stick together when sowing), but do not over‑dry.

Stimulants. You can add growth stimulants to the soaking water: Epin, Zircon, potassium humate, or micronutrients (boron, molybdenum, manganese) – they improve germination vigour and strengthen immunity (Аутко и др., 2012). Follow the product instructions for concentration and duration.

Bubbling (oxygen treatment). A more modern method – placing seeds in water saturated with air bubbles (aquarium compressor) for 15–18 hours at +20 °C. Bubbling significantly accelerates germination and increases germination rate, especially for seeds with lower vigour (Welbaum, 2015). However, at home, this method requires a compressor and water container, so it is not for everyone.

Caution: Germinated seeds (with a visible radicle) must be sown very carefully and only into moist soil, as the radicles are easily damaged. For mechanised sowing, germinated seeds are not used – they are usually dried to free‑flowing state. Therefore, for most home gardeners, simple soaking is optimal, not full germination.

Priority Scale: What Is Mandatory and What Can Be Skipped

To avoid confusion, here is a clear priority scale for the home gardener:

Practical Seed Preparation Algorithm for the Gardener

1. Select quality seeds – discard shrivelled, very small, or dark‑spotted ones.

2. Check if seeds are already treated – if they are coloured (red, green, blue), they are already treated. In this case, do not heat‑treat them, only light soaking in clean water.

3. If seeds are untreated – perform heat disinfection (48–50 °C, 20 minutes) or treat with a biological product (Fitosporin) according to instructions.

4. Soak seeds in warm water (+20 °C) for 12–24 hours (you may add a stimulant).

5. Dry seeds to free‑flowing state on clean cloth or paper (not in the sun).

6. Sow immediately after drying – long storage after soaking reduces germination.

These simple steps will give you healthy and uniform seedlings, the start of your strong cabbage plants.

Substrate Requirements

The ideal growing medium for cabbage seedlings must meet four key conditions:

1. Loose and aerated. Cabbage roots need oxygen. In dense, compacted soil they suffocate, growth slows, and the risk of root rots increases (Nonnecke, 1989). The medium should be light, crumbly, and not form a crust after watering.

2. Water‑holding capacity. At the same time, the medium should retain moisture well but not become waterlogged. The optimal balance is when water does not drain immediately but also does not stagnate. This is achieved by a proper ratio of organic and mineral components (Welbaum, 2015).

3. Nutritious. Young cabbage plants are very sensitive to nutrient deficiencies. In the first 2–3 weeks, they mainly consume nitrogen and phosphorus, and their supply must be available from the start. However, excess fertiliser (especially nitrogen) in the seedling medium is just as harmful as deficiency: it promotes stretching and weakening (Аутко и др., 2012).

4. Sterility (free of pathogens and weed seeds). In non‑sterile soil, pathogens of blackleg, root rots, and other diseases are highly likely to develop. Also, weeds that get into seedling containers quickly outgrow cabbage and suppress it (Starczev, 2021; Nonnecke, 1989).

Structure and Composition

Optimal particle size – medium or fine, without large clods or stones. Particles should be 0.5–5 mm in size to ensure good contact with seeds and roots while not impeding drainage (Аутко и др., 2012). In cell‑tray technology, the requirements are even higher: the substrate must be homogeneous, without large inclusions, to fill all cells evenly.

Basic components for mixing (recipes for hobbyists):

• Peat – the base of most potting mixes. Sphagnum peat is more fibrous and acidic (pH 3.5–4.5) and needs liming. Lowland peat is richer in nutrients, pH 5.5–6.5, but denser. An optimal blend uses both or a commercial neutralised peat (Аутко и др., 2012; Ториков и Сычев, 2018).
• Well‑rotted manure or compost – source of organic nutrition, improves structure and water‑holding capacity. Must be well decomposed (at least 2–3 years old), without ammonia smell. Add 20–30% by volume (Nonnecke, 1989).
• Turf soil – denser component, added for root stability. Collect from meadows where brassica crops have not been grown. Steam or bake to sterilise.
• Coarse sand or perlite – aerating agents, improve drainage and air exchange. Add 10–20% by volume (Welbaum, 2015). Sand should be washed, free of clay impurities.

Example composition of a good cabbage seedling mix (by volume):

• Neutralised peat – 4 parts
• Well‑rotted compost – 2 parts
• Turf soil – 2 parts
• Coarse sand or perlite – 1 part
• Per 10 litres of mix add: 20–30 g of complete mineral fertiliser (e.g., 13:12:19 + micronutrients) and a cup of wood ash (source of potassium and micronutrients, also a liming agent) (Аутко и др., 2012; Ториков и Сычев, 2018).

Commercial substrates: If you cannot prepare your own mix, you can purchase a specialised cabbage seedling mix or a universal "vegetable" mix. Choose reputable brands that specify pH and composition. Many manufacturers already include a starter dose of fertiliser, simplifying care.

Moisture Retention and Drainage

Cabbage does not tolerate drought, but waterlogging is also fatal. The medium should be moderately moist at all times. Test: squeeze a handful of mix in your fist – when released, it should hold its shape but crumble with light pressure. If it crumbles immediately – too dry; if water runs out – too wet (University of Minnesota, 2024).

To improve drainage, place a layer of fine gravel or perlite (1–2 cm) at the bottom of containers, and ensure drainage holes.

Sterilising the Growing Medium

Disinfecting the medium is mandatory, especially if you use components from the garden or are unsure of their cleanliness. Main methods for home conditions:

1. Steaming. Place the medium in a colander or cloth bag and hold over boiling water for 30–40 minutes. This kills most pathogens and weed seeds. Allow to cool for 1–2 days before use (Nonnecke, 1989).

2. Baking in the oven. Spread the medium in a thin layer on a baking tray and heat at 80–90 °C for 30–40 minutes. Higher temperatures destroy organic matter and make the soil sterile but "dead" – after baking, you should enrich it with beneficial microflora (e.g., water with a solution of Baikal‑EM or Fitosporin).

3. Biological treatment. The most modern method – water the medium with a solution of biofungicides (Trichodermin, Fitosporin, Alirin‑B) 2–3 days before sowing. This suppresses pathogens and simultaneously inoculates the substrate with beneficial microorganisms that protect the root system (Аутко и др., 2012). This method is especially recommended for cell‑tray growing, where loss of even a few plants is critical.

Important: Sterilise the medium 2–3 days before sowing so it can "rest" and, if you added microflora, it can become active. Sowing in freshly steamed medium is not recommended – it may be too dry or over‑wet.

pH of the Growing Medium

Cabbage grows best at pH 6.0–6.8 (slightly acidic to neutral) (Nonnecke, 1989; Ториков и Сычев, 2018; Welbaum, 2015). At more acidic pH (below 5.5), roots poorly absorb phosphorus, calcium, and molybdenum, leading to nutrient deficiencies, slowed growth, and increased disease susceptibility. At strongly alkaline pH (above 7.5), iron and boron uptake decreases.

How to check pH at home:

• Use litmus paper (sold at garden centres) – mix soil with distilled water (1:2), place a drop on the paper, compare colour with the scale.
• If litmus is unavailable, you can use indicator plants (e.g., horsetail and moss indicate acidic soil, nettle indicates neutral), but this is less accurate.

Adjusting pH: to raise pH (deacidify), add dolomite lime or chalk (about 1–2 cups per 10 litres of mix, depending on initial acidity). To lower pH (if too alkaline), use sulphur or acid peat, but this is rarely needed at home.

How to Prepare the Medium for Sowing: Step‑by‑Step

1. If preparing your own mix, 2–3 weeks before sowing, combine all components, add mineral fertiliser and dolomite lime, mix thoroughly.

2. 3–5 days before sowing, sterilise using your chosen method.

3. A day before sowing, moisten the medium to a "damp sponge" consistency (not wet!) and fill containers. Lightly firm to eliminate air pockets.

4. For cell‑tray growing, fill cells, firm lightly, and make holes for seeds (1–1.5 cm deep) using a marker or special tool.

5. On sowing day, check moisture – the medium should be uniformly moist but not wet. If in doubt, lightly mist with a spray bottle an hour before sowing.

Practical Takeaway: What Should a Gardener Choose?

The most reliable and easiest option – buy a high‑quality commercial cabbage seedling mix from a garden centre. It is already balanced in nutrition, pH, and sterility, with less hassle.

If you make your own – be sure to steam it and check pH. Do not skimp on sand or perlite – they are essential for structure.

Never use:

• fresh manure or undecomposed compost (they "burn" roots and may contain weed seeds) (Nonnecke, 1989).
• soil from the garden where brassicas were grown (diseases are transmitted through soil) (Аутко и др., 2012).
• soil that has been stored damp for a long time or frozen – its structure is damaged and it loses nutrients.

Quality growing medium is the key to healthy, stocky, transplant‑ready seedlings. Do not neglect this step!

Sowing Depth

The optimal sowing depth for cabbage seeds is 1–1.5 cm (Аутко и др., 2012; Ториков и Сычев, 2018; University of Minnesota, 2024). Cabbage seeds are small, and if buried too deep (more than 2 cm), they may not have enough strength to bring cotyledons to the surface – seedlings will be weak or may not appear at all. If sown too shallow (less than 0.5 cm), seeds may dry out before they can root, especially in dry indoor air.

Why exactly 1–1.5 cm? At this depth, seeds are in a zone of stable moisture, receive enough oxygen for respiration, and do not have to push through too thick a soil layer. In cell‑tray systems, where soil volume is limited, sowing depth is usually 0.8–1.2 cm (Welbaum, 2015).

Practical tip: Make furrows or holes 1 cm deep, place seeds, then cover with loose soil (the same substrate) and lightly firm the surface with your palm or a board. Firming ensures good seed‑to‑soil contact, which is important for imbibition and germination.

Spacing at Sowing

Spacing depends on the growing method:

1. Sowing in common boxes or containers. Optimal spacing – 3–5 cm between seeds in the row and 5–6 cm between rows (Nonnecke, 1989). This gives each plant enough space for initial growth, preventing excessive shading and competition. Denser sowing leads to elongated, weak seedlings, and pricking out becomes more difficult.

2. Sowing in cell trays. Sow 1–2 seeds per cell (the second as a backup, later remove the weaker one). Cell size for early cabbage – 4×4 or 5×5 cm (volume 18–65 cm³), for late – 3×3 or 4×4 cm (Аутко и др., 2012). In cell trays, seedlings do not need pricking out, and roots are not damaged at transplanting.

3. Sowing in peat pellets or pots. 1–2 seeds per pellet/pot. This method is convenient because the plant is transplanted together with the pot, without root damage (Ториков и Сычев, 2018).

Important: If using cell trays or pots, select only the largest and most uniform seeds – every seed counts. For boxes, you can sow slightly denser, but then you must prick out.

Temperature Regime Before Emergence

Temperature is the main factor determining the speed and uniformity of emergence. Cabbage seeds start germinating at +5 °C, but at such low temperatures the process takes 2–3 weeks, and many seeds may rot. The optimal temperature for germination is +18…+20 °C (Аутко и др., 2012; Nonnecke, 1989; Welbaum, 2015).

Recommended regime:

• Before emergence: maintain +18…+20 °C during the day and +16…+18 °C at night.
• At this temperature, emergence occurs on days 3–4 (Аутко и др., 2012; Старцев, 2021). This is the fastest and most reliable option.
• If you sow seeds and keep the temperature around +10 °C, emergence will take 10–12 days, but seedlings will be weaker and more susceptible to disease.

Important caveat: As soon as the first "loops" of seedlings appear (usually on days 3–4), the temperature must be immediately lowered to +8…+10 °C for 5–6 days. Otherwise, seedlings will stretch, becoming thin and weak (Nonnecke, 1989; Ториков и Сычев, 2018). This technique, called "temperature hardening", is essential for obtaining stocky, healthy seedlings. We will discuss it in more detail in the seedling care chapter.

Bottom heat: To speed germination, it is helpful to provide bottom heat (e.g., place containers on a warm windowsill above a radiator or use a seedling heat mat). With warmed soil, roots develop more actively and emergence is faster (University of Minnesota, 2024).

Moisture Before Emergence

From sowing to emergence, the growing medium must be uniformly moist but not wet. Excess water washes out seeds, causes rotting, and promotes fungal diseases (especially blackleg). Insufficient moisture leads to seed desiccation, preventing imbibition and germination.

How to maintain moisture correctly:

• Cover containers with a transparent lid, glass, or plastic film – this creates a greenhouse effect, retaining moisture and heat (Nonnecke, 1989).
• Remove the cover daily for 5–10 minutes for ventilation to prevent condensation, which encourages fungal diseases.
• Water only with a spray bottle, very gently, to avoid washing seeds. Use settled water at room temperature (Welbaum, 2015).
• Check moisture with a finger – the medium should be moist at 0.5–1 cm depth. If the surface begins to dry, mist lightly.

As soon as the first seedlings appear, remove the cover – now the seedlings need light and fresh air to prevent stretching and fungal infections (Oklahoma State, 2024).

Sowing Methods: Pros and Cons

For most home gardeners, the optimal choice is cell trays (for early and late varieties) or common boxes with subsequent pricking out (if cell trays are unavailable). Cell‑tray technology is considered the most advanced, producing high‑quality seedlings with minimal losses (Аутко и др., 2012; Welbaum, 2015).

Step‑by‑Step Sowing Algorithm

1. A day before sowing fill containers with prepared, moistened medium (to "damp sponge" consistency), lightly firm, and make furrows (holes) 1–1.5 cm deep.

2. On sowing day place seeds in furrows with 3–5 cm spacing (or 1–2 seeds per cell).

3. Cover seeds with loose soil 1 cm thick, lightly firm the surface.

4. Mist the surface with a spray bottle to moisten the top layer.

5. Cover containers with a transparent lid or film and place in a warm place (temperature +18…+20 °C).

6. Ventilate daily and monitor moisture.

7. When seedlings emerge (days 3–4) – lower temperature to +8…+10 °C for 5–6 days, remove cover, and provide good lighting.

What Can Go Wrong and How to Prevent It

• Uneven emergence. Causes: uneven sowing depth, uneven moisture in different parts of the container, or poor‑quality seeds. Solution: sow only calibrated seeds, maintain uniform depth, and ensure even watering.
• No germination. Possible causes: too deep sowing, dry medium, very low temperature, or old seeds. Solution: check conditions and, if necessary, re‑sow following all recommendations.
• "Blackleg" (stem rot at the base). Cause: overwatering, poor drainage, non‑sterile medium, lack of light. Solution: use sterile medium, ensure drainage, water moderately, ventilate, and at first signs treat with a biofungicide (Аутко и др., 2012).

Proper sowing is 50% of the success in obtaining strong and healthy seedlings. In the next chapter, we will discuss how to care for seedlings so they become stocky, transplant‑ready plants.

Light: The Main Factor Preventing Stretching

Cabbage is a long‑day, light‑loving plant. In the first month, it is especially sensitive to insufficient light. Under low light, seedlings stretch, become thin and brittle, and form loose, weakened tissues prone to disease (Nonnecke, 1989; Welbaum, 2015).

What you need to know about light for cabbage seedlings:

• Day length. The optimal photoperiod for cabbage seedlings is 14–16 hours. In March, when most gardeners sow early cabbage, natural light in the central zone is still insufficient. Therefore, supplementary lighting is essential using grow lights or cool‑spectrum fluorescent lights (Аутко и др., 2012; University of Minnesota, 2024).
• Light intensity. Place seedlings at the brightest windows (south, south‑east). Distance from lamps to plants – 10–15 cm, raising lamps as plants grow. Use wide‑spectrum grow lights, but regular fluorescent tubes also work (Ториков и Сычев, 2018).
• Lighting schedule. Turn on lamps in the morning and evening so that total day length is at least 14 hours. On cloudy days, provide light all day. If not done, seedlings will inevitably stretch, and it will be hard to correct later (Nonnecke, 1989).
• Signs of light deficiency: pale green colour, long internodes, thin stem, plants leaning toward the window. If these symptoms appear, immediately increase supplementary lighting.

Important: If you cannot provide supplementary lighting, sow seedlings 2–3 weeks later – in late April, when day length is longer. But then transplanting will also shift, which may not be acceptable for early varieties.

Temperature: The Key to Stocky Seedlings

The temperature regime for cabbage seedlings changes with development phase. The most common and serious mistake by beginners is keeping seedlings warm (above +20 °C) after emergence, causing them to stretch immediately.

Correct temperature schedule:

Sources: (Аутко и др., 2012; Nonnecke, 1989; Старцев, 2021; Welbaum, 2015).

Why this works: Right after emergence, seedlings begin active elongation of the hypocotyl (stem). If kept warm at this time, the hypocotyl elongates upward toward light and becomes thin. Low temperatures (around +8…+10 °C) slow this elongation but do not stop root development and true leaf formation. As a result, the plant invests energy in root strengthening and stem thickening, not in elongation (Nonnecke, 1989).

Practical tips:

• After emergence, move containers to a cool place for 5–6 days (glazed balcony, cold greenhouse, or windowsill with a slightly open window, but without drafts).
• Thereafter, maintain moderate temperatures: on sunny days up to +18 °C, on cloudy days up to +16 °C, at night +8…+12 °C. Such day‑night fluctuations harden the plants, making them more resistant to field conditions (Welbaum, 2015; University of Minnesota, 2024).
• If seedlings start to stretch, immediately lower temperature and increase light. This may stop stretching, but if it has gone too far, such plants should be discarded – they will give poor yields.

Watering: Balancing Moisture and Air

Cabbage likes moisture, but excess is the main cause of blackleg and root rots. Young roots must breathe, so waterlogged, compacted medium is fatal (Nonnecke, 1989; Oklahoma State, 2024).

Rules for watering cabbage seedlings:

• Frequency. Water only when the top 1–2 cm of the medium has dried. Do not allow the root ball to dry out completely, but do not overwater. On average, in a warm room with good light, watering is needed every 2–3 days. In a cool room, less often (University of Minnesota, 2024).
• Amount. Water moderately, so that water penetrates the entire root zone but does not stagnate in the tray. Drain excess water from the tray after 15–20 minutes.
• Water. Use only settled water at room temperature (+20…+25 °C). Cold tap water stresses roots and may trigger diseases (Аутко и др., 2012).
• Method. For young seedlings, use a spray bottle or bottom watering to avoid washing soil and damaging tender stems. As plants grow, switch to careful watering at the base using a long‑spout watering can.
• Signs of overwatering: mould on the surface, wilting despite wet soil, stem rot at the base (blackleg). At first signs, stop watering, dry the medium, treat with a biofungicide.

Ventilation: Fresh Air Against Diseases

Stagnant, humid air around seedlings is an ideal environment for fungal diseases (grey mould, blackleg, downy mildew) (Аутко и др., 2012; Nonnecke, 1989). Regular ventilation reduces humidity, strengthens plants, and prepares them for open ground.

How to ventilate properly:

• Daily, especially in greenhouses and polytunnels, open vents or lift film for 10–15 minutes, gradually increasing the time.
• Avoid drafts, especially in the first 2 weeks after emergence – they can desiccate tender leaves and cause lodging.
• If seedlings are on a windowsill, regularly open the window (but not in freezing weather). You can provide brief ventilation even in winter, shielding seedlings from direct cold airflow.
• On sunny days when outdoor temperature is above +5 °C, it is beneficial to take seedlings out for a few hours to a glazed balcony (this is also part of hardening, which we will cover in a separate chapter).

Preventing Stretching: A Holistic Approach

Stretching is the most common problem for beginners. It occurs due to an imbalance of three factors: light, temperature, and nutrition. To prevent stretching, act on all three fronts:

1. Light. Provide 14–16 hours of intense light. If light is insufficient, supplement. When light is low, lower temperature – this partially compensates for light deficiency (Nonnecke, 1989).

2. Temperature. After emergence, always reduce temperature to +8…+10 °C for 5–6 days. Then maintain moderate warmth (+14…+18 °C day, +8…+12 °C night). The less light, the lower the temperature should be.

3. Nutrition. Do not over‑feed nitrogen in the first 2–3 weeks. Nitrogen stimulates rapid leaf and stem growth, which at low light exacerbates stretching. The first fertiliser is given only after 2–3 true leaves appear, and it should contain more phosphorus and potassium than nitrogen (Welbaum, 2015; Ториков и Сычев, 2018).

4. Sowing density. Do not overcrowd. In dense plantings, plants compete for light and stretch faster. Pricking out or thinning helps solve this.

5. Growth regulators. As a last resort, if seedlings begin to stretch, you can use growth regulators (e.g., Athlete) that slow stem elongation and stimulate root development. But this is more of a "first aid" than a primary strategy. Use strictly according to instructions and only when absolutely necessary (Аутко и др., 2012).

Signs of high‑quality, non‑stretched seedlings:

• Short, thick stem (0.4–0.6 cm diameter at base).
• Very short internodes.
• Dark green, firm leaves, no yellowing.
• Well‑developed, white root system, no rot.

If you see that seedlings have started to stretch, do not despair: you can lower temperature, increase light, and possibly prick out with burying to the cotyledons (this stimulates adventitious root formation). However, severely overgrown seedlings (thin stem, long internodes) will not produce a good yield – it is better not to use them.

What Are Pricking Out and Potting On?

Pricking out – transplanting seedlings from a common container (box, flat) into individual pots, cell trays, or a more spacious place in the same box. During pricking, the tip of the taproot is often pinched to stimulate lateral root growth (Nonnecke, 1989; Welbaum, 2015). However, for cabbage, root pinching is often omitted to avoid slowing growth, but the transplanting itself gives each plant more space.

Potting on (repotting) – moving a plant from a smaller to a larger container without disturbing the root ball. In potting on, roots are not damaged, the plant does not experience stress, and growth continues without interruption. Potting on is used for seedlings grown in cell trays or small pots when roots have filled the volume and there is still time before transplanting (Ториков и Сычев, 2018).

When Is Pricking Out Needed?

1. Sowing in common boxes or flats. If you sowed densely (in a box or tray), pricking out is unavoidable. Seedlings start competing for light and nutrients, stretch, and roots become tangled. Pricking out gives each plant individual space and stimulates development of a strong root system (Nonnecke, 1989).

2. Need to select the best plants. Pricking allows you to discard weak, diseased, or deformed seedlings, keeping only the strongest and most promising (Welbaum, 2015).

3. Growth delay (for early sowings). Sometimes seedlings are ready to transplant, but weather does not permit (frost, cold soil). Pricking into larger containers slows growth and buys time without loss of plant quality (Аутко и др., 2012).

4. Stimulating root formation. When transplanting with burying the stem up to the cotyledons, additional (adventitious) roots form on the stem, making the root system more powerful. This is especially useful for cabbage, which readily produces adventitious roots when hilled (Nonnecke, 1989; Старцев, 2021).

When Is Pricking Out Not Needed (or Even Harmful)?

1. Sowing in cell trays or individual containers. If you sowed directly into cell trays (4×4 or 5×5 cm), peat pots, or pellets, pricking out is unnecessary. Each plant grows in its own volume, roots do not tangle, and at transplanting the root ball remains intact. This is the gentlest method, ensuring 100% survival (Аутко и др., 2012; Welbaum, 2015).

2. Direct sowing in the ground (no‑seedling method). Pricking is impossible by definition.

3. Overgrown seedlings. If seedlings are already severely stretched and overgrown, pricking may be too stressful and not give the desired effect. It is better to use potting on or transplant such plants directly into the ground, burying the stem.

General rule: Prick out only plants that were sown in common containers. If you use cell trays or pots, transplant plants only once – to their final position in the garden (Nonnecke, 1989; University of Minnesota, 2024).

Timing for Pricking Out

The optimal time for pricking is the 1–2 true leaf stage (excluding cotyledons). This usually occurs 10–15 days after emergence (Аутко и др., 2012; Ториков и Сычев, 2018).

Why this stage? At this time, the root system is not yet too extensive, and roots can be separated without serious damage. Seedlings are strong enough to withstand transplanting but have not yet started competing for light and nutrients. Later pricking (at 3–4 leaves) is more traumatic: roots are heavily intertwined and difficult to separate without damage.

Important: If seedlings emerged very densely, you can prick out slightly earlier – at the cotyledon stage, when the first true leaf is just starting to form. But this requires more skill, as seedlings are very delicate (Nonnecke, 1989).

Pricking Out Technique: Step‑by‑Step

1. Prepare containers and medium. Use individual pots (plastic, peat) or cell trays with cells not smaller than 5×5 cm, preferably 6×6 cm for early varieties (4×4 cm is enough for late ones). Fill with the same medium used for sowing (or slightly richer), lightly moisten.

2. Water seedlings in the box thoroughly 2–3 hours before pricking. This makes root extraction easier and reduces damage.

3. Gently lift the seedling using a small trowel, fork, or even a toothpick. Try to take the plant with a soil clump, avoiding touching the stem with fingers (cabbage stems are very fragile). Better to hold the seedling by the cotyledon leaf – it is less sensitive to damage (Nonnecke, 1989).

4. Examine the roots. Remove any excessively long or damaged roots (but for cabbage, this is optional). If the root is very long, it can be lightly pinched (by 1/3 of length), but for cabbage this is rarely done, as it tolerates pricking without pinching (Starczev, 2021).

5. Make a hole in the new pot (with a finger or dibber) deep enough to bury the plant up to the cotyledon leaves. This is very important! Burying the stem to the cotyledons promotes the formation of extra roots, making the plant more powerful and stable (Аутко и др., 2012; Nonnecke, 1989).

6. Place the seedling in the hole, carefully spread the roots (they should not bend upward). Cover with medium and lightly firm around the stem.

7. Water thoroughly with warm water (you can add Rootone or a weak solution of complete fertiliser). After watering, the medium will settle; add a little more dry medium if needed.

8. Shade the seedlings for the first 2–3 days after pricking (with paper, netting, or simply place them not on the sunniest windowsill). This reduces evaporation and helps plants establish faster (Welbaum, 2015).

Temperature and Light Regime After Pricking Out

Immediately after pricking, plants experience stress. To help them recover, provide gentle conditions:

• Temperature: first 2–3 days keep at +16…+18 °C day and +12…+14 °C night. Then gradually reduce to normal regime (+14…+18 °C day, +8…+12 °C night) (Аутко и др., 2012; Nonnecke, 1989).
• Light: Provide bright, diffused light. If pricking was done on a cloudy day, supplementary lighting is especially important. After 2–3 days of shading, return plants to the brightest windowsill or under lamps.
• Watering: In the first 3–4 days, water very moderately, only as the top layer dries. Overwatering at this stage is particularly dangerous – roots are not yet actively working, and water can cause rotting (Nonnecke, 1989).

What Is Potting On and When to Use It

Potting on – transplanting a plant into a larger container with the entire root ball intact, without disturbing the roots. Potting on is used in the following cases:

• When seedlings grown in cell trays or small pots have outgrown them, but transplanting outdoors is still too early (roots have filled the volume, and the plant is suffering from crowding).
• When you need to give the plant extra space for growth without stress.
• When you want to avoid the growth check typical of pricking.

How to pot on:

1. Water the plant moderately a day before potting so the root ball holds together.

2. Carefully remove the plant from the old container (turn the pot upside down, tap the bottom).

3. Place the root ball into a new container (2–3 cm larger than the old one) and fill around with fresh medium.

4. Lightly firm and water.

5. Continue care as for normal seedlings.

Potting on does not cause a growth check, and the plant continues developing without interruption (Ториков и Сычев, 2018; Welbaum, 2015).

Advantages and Disadvantages of Pricking Out

Practical Takeaway: To Prick or Not to Prick?

• Prick out if you sowed in common boxes and want strong, stocky seedlings with a well‑developed root system. This is the classic and reliable method.
• Do not prick if you used cell trays, peat pots, or pellets – in that case, plants grow individually and pricking is unnecessary.
• Use potting on if seedlings in small containers have outgrown them and need more space before transplanting.

Important: Cabbage is one of those crops that tolerates pricking very well and even benefits from it (especially when buried to cotyledons). So even if you are a little late or not perfect, the chances of successful recovery are very high (Nonnecke, 1989; Starczev, 2021).

Why Is Hardening Off Necessary?

Seedlings grown indoors or in a greenhouse get used to a gentle environment: stable temperatures, high humidity, no wind, and moderate light. In the open field, they face sharp temperature fluctuations, drying winds, intense sunlight, and possible night frosts.

Hardening off is a set of measures that gradually acclimatises plants to these stressors. As a result, physiological changes occur in the cells:

• Accumulation of sugars and dry matter in tissues, increasing cell sap concentration and lowering the freezing point (Nonnecke, 1989; Welbaum, 2015).
• Thickening of the cuticle (waxy layer) on leaves, reducing transpiration and protecting against sunburn (Аутко и др., 2012).
• Development of a more powerful root system and strengthening of stem mechanical tissues, improving resistance to lodging and wind (Ториков и Сычев, 2018).

Without hardening:

• Plants may get sunburn (white or brown spots on leaves) on the first day after transplanting.
• In sudden cooling to +2…+5 °C, unhardened seedlings may stop growing, and frost may kill them.
• Transplanting will be accompanied by prolonged wilting and a growth delay of 1–2 weeks, negating the advantage of early growing (Nonnecke, 1989).

Conclusion: Hardening is an investment of a few days that pays off with rapid establishment, early and abundant harvests.

When to Start Hardening?

Hardening should begin 1–2 weeks before the intended transplanting date (Аутко и др., 2012; University of Minnesota, 2024; Oklahoma State, 2024). Specific timing depends on seedling age and weather:

• Early cabbage (age 45–55 days) – start hardening about 10–12 days before transplanting.
• Mid‑season and late cabbage (age 35–45 days) – 7–10 days before transplanting.

Important condition: By the start of hardening, seedlings should have 4–6 true leaves and be sufficiently strong. Hardening overgrown or weakened seedlings is ineffective and may damage them (Nonnecke, 1989).

Adaptation Plan: Step‑by‑Step Schedule

Hardening is done gradually, increasing stress day by day. Below is a general schedule adaptable to your conditions.

Hardening Specifics for Different Growing Systems

Signs of Successful Hardening

Seedlings are considered ready for transplanting if they:

• Have a bluish‑green tint (indicator of protective substance accumulation and waxy coating) (Nonnecke, 1989).
• Stem is firm, not breaking when gently bent.
• Leaves are firm, glossy, no wilting after sun exposure.
• Plants tolerate night temperatures down to +2…+3 °C without visible damage (Аутко и др., 2012).

Common Mistakes and How to Avoid Them

Practical Takeaway

Hardening is not complicated but is an essential step that takes about 1–2 weeks and requires daily attention. Its main rule is gradualness and moderation. Start small: reduce watering and temperature, then slowly accustom to sun and wind. Remember that hardened seedlings:

• Easily withstand transplanting.
• Are not afraid of short‑term frosts down to –3…–5 °C.
• Quickly resume growth in the field.
• Give earlier and higher‑quality yields.

Seedling Age

Cabbage has a fairly wide "window" of readiness, but there are optimal age ranges for each maturity group:

Sources: (Аутко и др., 2012; Nonnecke, 1989; Старцев, 2021; Ториков и Сычев, 2018).

Why age matters: If you transplant seedlings that are too young (less than 30 days), they have not yet built enough root mass and nutrient reserves, slowing establishment. If you hold them too long (over 60 days for early or 45 days for late), roots outgrow the pot volume, become twisted, and suffer from nutrient deficiency. Such seedlings, after transplanting, stay "stuck" for a long time, get sick, and produce loose, small heads (Nonnecke, 1989; Welbaum, 2015).

Important: Seedling age is counted from the day of emergence (not sowing). Consider that different varieties may emerge 2–3 days apart, especially with temperature fluctuations.

Number of True Leaves

This is the most visual and reliable criterion. Optimal cabbage seedlings should have 4–6 well‑developed true leaves (excluding cotyledons) (Nonnecke, 1989; Oklahoma State, 2024; University of Minnesota, 2024).

What these numbers mean:

• 4 leaves – minimum readiness threshold. Seedlings have sufficient assimilation surface for photosynthesis and have stored the required nutrients in the stem and roots.
• 5–6 leaves – optimal. Such plants have a strong root system, thick stem, and can quickly adapt to field conditions (Welbaum, 2015).
• More than 6 leaves (for early varieties) or 7–8 (for late) – a sign of overgrowing. Plants begin to compete in the container, roots tangle, and stems may stretch even if you followed the regime.

Nuance: Varieties differ in development rate. Early varieties produce leaves faster, and by 45 days they often have 5–6 leaves. Late varieties develop slightly slower, and at 35–40 days they often have only 4–5 leaves – this is normal (Nonnecke, 1989).

Root System Condition

What is hidden underground is as important as the above‑ground part. Quality seedlings should have:

• A well‑developed, branched root system of white or light cream colour, with no signs of rotting, darkening, or twisting (Welbaum, 2015).
• Roots should fill almost the entire pot or cell volume, but not protruding heavily through drainage holes (this is a sign of overgrowing) (Ториков и Сычев, 2018).
• When removed from the container, the root ball should hold its shape and not crumble – meaning roots have sufficiently bound the medium (Nonnecke, 1989).

Check: 1–2 days before planned transplanting, randomly check 2–3 plants from different parts of the batch. Gently remove the root ball from the pot. If roots are white, succulent, and evenly bind the ball – great. If roots are sparse and few – seedlings not yet ready; need a delay of 5–7 days. If roots are dark, brown, with an unpleasant smell – sign of disease; discard such plants (Nonnecke, 1989; Аутко и др., 2012).

Signs of Quality (Non‑overgrown) Seedlings

Here is a complete list of external signs to distinguish ideal seedlings from "overgrown" or "under‑prepared":

Sources: (Nonnecke, 1989; Welbaum, 2015; Ториков и Сычев, 2018; Старцев, 2021).

Readiness for Transplanting Considering Weather Conditions

Even if seedlings meet all the above parameters, transplanting can only be done when weather conditions are suitable. Here are the main guidelines:

1. Soil temperature at 10–15 cm depth must be at least +8…+10 °C (Nonnecke, 1989; Iowa State, 2024). In cold soil, roots do not function, and seedlings may not establish. To check, simply insert a thermometer into the ground in the morning.

2. Daytime air temperature – steadily above +10 °C, and nights not below +2…+3 °C (Oklahoma State, 2024). Frosts down to –2…–3 °C are tolerated by hardened seedlings, but it is better to avoid transplanting during severe frost threats.

3. Soil should be moderately moist, but not waterlogged (not "swimming"). In wet soil, roots suffocate and rot, especially in cold weather (University of Minnesota, 2024).

4. Weather forecast for 7–10 days – favourable: no prolonged rains, strong winds, or sharp cooling. If cooling is expected, better to delay transplanting by 3–5 days or prepare cover material.

Approximate transplanting dates for central zone (Russia example):

• Early varieties: first decade of May (1–10 May) – provided soil is warm enough.
• Mid‑season and late: third decade of May – first decade of June (20 May – 5 June).
• In southern regions, dates shift 10–15 days earlier; in northern – 10–15 days later.

What to Do If Weather Prevents Transplanting on Time?

Sometimes seedlings are ready, but weather fails – prolonged rain, cold, frost. In such cases, apply these techniques:

1. Slow growth (cold storage). Lower temperature to +6…+8 °C day and +4…+5 °C night. Reduce watering. This stops growth and "preserves" seedlings for 5–10 days without quality loss (Nonnecke, 1989; Ториков и Сычев, 2018).

2. Potting on into larger containers. If seedlings start to overgrow and transplanting is not possible, pot them on into pots 2–3 cm larger. This gives roots new space and delays senescence. But this only works if you have space and medium (Welbaum, 2015).

3. Pinching the growing point (not recommended for beginners). As a last resort, some crops are topped to delay growth, but for cabbage this may result in multiple small heads rather than one large one, so it is better not to risk (Nonnecke, 1989).

4. Transplant with covering. If seedlings are overgrown and weather is moderately cold, you can transplant them into the ground and cover with non‑woven material (agrospan, lutrasil) for 1–2 weeks. This protects from frost and wind, and plants will establish successfully even in less‑than‑ideal conditions (Аутко и др., 2012; Iowa State, 2024).

Practical Takeaway: Readiness Checklist

Before transplanting, check seedlings against this list:

• [ ] Age matches the recommended for the variety (45–55 days for early, 35–45 for mid‑late).
• [ ] Plant has 4–6 true leaves.
• [ ] Stem is thick (0.4–0.6 cm), short, not stretched.
• [ ] Leaves are dark green, firm, without spots or damage.
• [ ] Root system white, branched, binding the ball.
• [ ] Seedlings have undergone full hardening (tolerate sun, wind, and night temperatures +2…+3 °C).
• [ ] Soil temperature in the bed is above +8 °C.
• [ ] Weather forecast is favourable for the next 7–10 days.

If all points are met – you can safely transplant seedlings to their permanent place. In the next, final, chapter, we will detail how to conduct transplanting to minimise stress and give plants a good start.

Optimal Time for Transplanting

Transplant seedlings when:

• The danger of severe frost has passed (hardened seedlings tolerate short frosts down to –2…–3 °C) (Nonnecke, 1989; Аутко и др., 2012).
• Soil at 10–15 cm depth has warmed to +8…+10 °C (Iowa State University Extension, 2024; University of Minnesota Extension, 2024).
• The forecast for the next 5–7 days is favourable (no prolonged rain or sharp cooling).

The best time of day for transplanting – late afternoon (after 4–5 p.m.) or a cloudy day. This allows plants to avoid intense sunlight in the first hours after transplanting and gives them time to recover turgor overnight (Nonnecke, 1989; Ториков и Сычев, 2018).

Approximate dates for different zones (Russia example):

• Southern regions: late March – early April (early varieties), April (late varieties).
• Central zone: first decade of May (early varieties), third decade of May – first decade of June (mid‑season and late) (Аутко и др., 2012; Ториков и Сычев, 2018).
• Northern regions (Ural, Siberia, northern Non‑Black Earth): late May – early June (all varieties) (Starczev, 2021).

Bed Preparation

The site for cabbage should be:

• Sunny (at least 6–8 hours of direct sun per day). In shade, cabbage stretches, forms loose, small heads, or does not set heads at all (Nonnecke, 1989; Welbaum, 2015).
• With fertile, well‑drained soil at pH 6.0–6.8 (Welbaum, 2015; Oklahoma State University Extension, 2024).
• With good preceding crop (not brassica crops for the last 3–4 years). Best predecessors – legumes, cucumbers, potatoes, onions, carrots (Аутко и др., 2012; Ториков и Сычев, 2018).

Soil preparation:

1. In autumn or 2–3 weeks before transplanting, apply organic fertilisers (well‑rotted manure or compost – 40–60 t/ha or 5–6 kg/m² for home gardens) (Nonnecke, 1989; Ториков и Сычев, 2018).

2. In spring (7–10 days before transplanting), loosen soil to 20–25 cm depth, remove weeds, apply mineral fertilisers (N – 90–120 kg/ha, P₂O₅ – 90–120, K₂O – 120–180, calculated as active ingredient) (Аутко и др., 2012).

3. A day before transplanting, water the bed thoroughly so the soil is moist to 15–20 cm depth. This ensures good root‑to‑soil contact (University of Minnesota, 2024).

4. If necessary, form ridges or raised beds. In regions with excessive moisture, planting on ridges 15–20 cm high is recommended to improve drainage and soil warming (Аутко и др., 2012; Ториков и Сычев, 2018).

Planting Patterns (Density)

Plant density depends on the maturity group and head size. Optimal schemes (based on Аутко и др., 2012; Nonnecke, 1989; Ториков и Сычев, 2018):

Why density matters: Denser planting gives smaller heads but higher total yield per area. For early produce (small heads), use denser schemes. For large heads and late storage, use wider spacing (Welbaum, 2015; Nonnecke, 1989).

For home gardens: Typically use row spacing 60–70 cm and in‑row spacing 30–50 cm depending on variety. Row spacing should match the width of your cultivator (if you plan mechanical cultivation).

Transplanting Technique: Step‑by‑Step Algorithm

1. 2–3 hours before transplanting, water seedlings thoroughly in pots or trays so the root ball is moist and can be easily removed without root damage (Nonnecke, 1989; Welbaum, 2015).

2. Prepare holes deep enough to bury the stem up to the first true leaves (or cotyledons if seedlings are slightly stretched). Spacing between holes according to chosen scheme (see table above). Add a handful of compost and 1 tablespoon of wood ash to the bottom of each hole (source of potassium and micronutrients) (Ториков и Сычев, 2018).

3. Carefully remove the plant from the container, trying not to damage the root ball. For cell‑tray plants, squeeze the cell from below and push out the ball. For pots, invert and tap the bottom (Nonnecke, 1989).

4. Place the plant in the hole so that the stem is buried to the level of the first true leaves (or cotyledons if slightly stretched). Burying stimulates formation of additional adventitious roots, improving nutrition and stability (Nonnecke, 1989; Старцев, 2021; Ториков и Сычев, 2018).

5. Fill the hole with soil, lightly firming around the stem. Roots must be fully covered, with no air pockets (Welbaum, 2015).

6. Water each plant thoroughly at the base – at least 0.5–1 litre per plant (you can add a weak solution of complete fertiliser or Rootone to stimulate rooting) (Аутко и др., 2012; University of Minnesota, 2024).

7. After watering, when water has soaked in, lightly cover the surface around the stem with dry soil or peat to reduce evaporation and prevent crusting (Nonnecke, 1989; Ториков и Сычев, 2018). This also protects the root collar from overheating.

8. Shading for the first 2–3 days (if transplanting in sunny weather) using non‑woven material, newspapers, or more frequent watering. This reduces evaporation and helps plants establish faster (Iowa State, 2024).

Post‑transplant Care

In the first 7–10 days after transplanting, the main goal is to ensure rapid rooting. For this:

• Watering. In the first week, water every other day (daily in hot weather), 0.5–1 L per root. Then switch to 1–2 times a week (1–2 inches of water, i.e., 2.5–5 cm), maintaining soil moisture at 75–80% of field capacity (Nonnecke, 1989; Welbaum, 2015). For late cabbage, stop watering 3–4 weeks before harvest to improve storage (Аутко и др., 2012; Ториков и Сычев, 2018).
• Cultivation and hilling. After each watering or rain, cultivate between rows to 6–8 cm depth to break soil crust and improve aeration. 2–3 weeks after transplanting, perform the first hilling with moist soil – it stimulates adventitious root formation and increases plant stability (Nonnecke, 1989; Ториков и Сычев, 2018).
• Fertilising. First fertilisation – 12–14 days after transplanting, with nitrogen fertiliser (urea or ammonium nitrate) at 10–15 g/m² to stimulate leaf growth. Second – at the start of head formation (4–6 weeks later), with phosphorus and potassium dominance (20–25 g/m² of complete fertiliser) (Nonnecke, 1989; Аутко и др., 2012). For storage cabbage, the last fertilisation should be no later than 2 months before harvest (Ториков и Сычев, 2018).
• Removing dead plants. If some plants die within 5–7 days after transplanting, replace them with reserve seedlings (if available). Plant replacements at the same time and with the same care (Nonnecke, 1989).

Protection Against Frost, Pests, and Diseases

Frost: Even hardened seedlings can suffer during a sharp cold spell below –3…–5 °C. Use cover material (agrospan, lutrasil) at night during the first 1–2 weeks after transplanting, especially in risky farming zones (Аутко и др., 2012; Iowa State, 2024).

Pests: Young seedlings are favourite food for flea beetles, cabbage flies, aphids, and caterpillars. For protection:

• Use non‑woven covers immediately after transplanting – they physically block pests at early stages (University of Minnesota, 2024; Oklahoma State, 2024).
• If flea beetles appear, dust plants with a mixture of ash and tobacco dust (1:1) or use approved insecticides (e.g., Decis, Actellic) strictly according to instructions (Аутко и др., 2012; Oklahoma State, 2024).
• Against cabbage flies, apply insecticidal granules to the soil around plants or water with solutions (Nonnecke, 1989; Старцев, 2021).

Diseases: For prevention of blackleg, root rots, and vascular bacteriosis:

• Follow crop rotation (return cabbage to the same plot no earlier than 3–4 years) (Аутко и др., 2012; Welbaum, 2015).
• Avoid water stagnation in the root zone.
• At the first signs of disease (wilting, yellowing, spots), remove diseased plants and treat the remaining with biofungicides (Fitosporin, Trichodermin) or copper‑based products (Oklahoma State, 2024; Nonnecke, 1989).

Signs of Successful Establishment

You can tell that seedlings have taken and are actively growing by the following signs:

• Appearance of a new leaf (growth of the central growing point) within 5–10 days after transplanting – the most reliable sign (Nonnecke, 1989).
• Restoration of leaf turgor – leaves become firm, glossy, pointing upward or horizontally (not drooping).
• Change in colour from pale green to bright green (indicator of active photosynthesis).
• No wilting even during hot hours (after 10–14 days) – evidence that roots have fully recovered and supply water to the plant (Welbaum, 2015).

If after 2 weeks plants look depressed, yellow, or show no growth – it is worth checking the root system (for rot or pest damage) and, if necessary, applying fertiliser or treatment.

Conclusion

Proper transplanting is the final and decisive step towards a bountiful cabbage harvest. Remember three main rules:

1. Transplant only hardened, healthy seedlings with 4–6 true leaves.

2. Water generously and shade in the first days after transplanting.

3. Provide regular care – watering, cultivation, fertilising, and pest protection.

By following these guidelines, you give your plants a good start and create the foundation for forming dense, juicy, and tasty heads.