Open ground vs. Indoor ground

Origin of the Crop

Cucumber (Cucumis sativus) originates from tropical and subtropical regions of India, where it was cultivated over 3,000 years ago (Nonnecke, 1989). Like other members of the Cucurbitaceae family, it evolved in warm, humid climates with long growing seasons.

This evolutionary history has shaped all of the plant's key characteristics:

• Heat-loving nature. Cucumber seeds begin to germinate at temperatures no lower than 12–13°C, with the most vigorous sprouting occurring at 25–30°C (Котов and Адрицкая, 2016). Plant growth slows below 15°C and stops entirely at 10°C. The optimal temperature for growth and fruiting is 20–28°C during the day and no lower than 16–18°C at night.
• Moisture-loving nature. Cucumber is the most moisture-loving vegetable crop. It demands not only high soil moisture but also high air humidity. Optimal soil moisture is about 80% of field capacity, while relative air humidity should be 85–90% (Welbaum, 2015). With insufficient moisture, plants stop growing, fruit quality deteriorates, and bitterness appears.
• Demand for soil aeration. The cucumber's root system is located in the surface soil layer and is highly sensitive to oxygen deficiency. Overwatering leads to root hair dieback and plant death.
• Stress sensitivity. Any unfavorable factors—sharp temperature fluctuations, insufficient or excess moisture, poor nutrition—affect yield. Under stress, plants produce more male flowers, ovaries may drop, and fruits acquire a bitter taste due to cucurbitacin accumulation (Welbaum, 2015).

Fruiting Duration and Day Length

Cucumber is a short-day plant, although many modern varieties are day-length neutral. Under short-day conditions (10–12 hours), plants transition to fruiting more quickly. Under long-day conditions, vegetative mass grows more vigorously, but fruiting may be delayed (Котов and Адрицкая, 2016).

Under optimal conditions, cucumber can bear fruit continuously for 2–3 months. However, in open ground, this period is often limited by weather—autumn cooling or summer heat that stresses plants.

Understanding these features helps you make an informed choice of growing method. Cucumber does not forgive mistakes: its tropical nature requires conditions as close to natural as possible. This is why the choice between open ground and a greenhouse is so important.

2.1. Advantages of Open Ground

Economic accessibility. Open ground does not require capital investments in greenhouses, heating systems, or supplementary lighting. All costs are limited to seeds, fertilizers, and basic plant protection products (Nonnecke, 1989). This is especially important for gardeners just starting to cultivate this crop.

Natural pollination. In open ground, cucumber pollination is carried out by bees, bumblebees, and other insects. This is especially important for bee-pollinated varieties and hybrids, where male and female flowers are on the same plant. With good insect activity, fruit set is high, and the gardener does not need to spend time on manual pollination. However, it is worth remembering that in cold or rainy weather, bee activity is limited, which can affect yield (Welbaum, 2015).

Lower risk of overheating. Unlike greenhouses, plants in open ground rarely suffer from critical overheating (above 35°C) if regular watering is provided. Natural air circulation prevents heat stress, at which pollen becomes sterile and ovaries drop. This is especially relevant in southern regions with hot summers (Котов and Адрицкая, 2016).

Natural flavor and fruit density. Many gardeners note that open-ground cucumbers have a richer aroma and crunchier texture. This is due to the natural light regime, daily temperature fluctuations, and lower water content in tissues compared to greenhouse-grown fruits. Additionally, open-ground cucumbers typically have thicker skin, which improves their shelf life and suitability for pickling (Welbaum, 2015).

2.2. Disadvantages and Risks of Open Ground

Yield instability due to weather. Cucumber is a tropical crop, and any deviations from optimum reduce productivity. Cold, rainy summers, sharp temperature fluctuations, prolonged droughts—any of these can lead to nearly complete fruit failure. At temperatures below 15°C, growth stops, and during prolonged cold spells (below 10°C), plants may die (Nonnecke, 1989).

Vulnerability to diseases and pests. In open ground, cucumbers are much more often affected by infections spread by rain, wind, and insects. The most dangerous are:

• Downy mildew (peronospora) — develops in high humidity and frequent rain. Affects leaves, reducing photosynthesis, and without treatment, plants can die within 1–2 weeks (Quesada-Ocampo, 2022).
• Powdery mildew — appears in hot weather with fluctuating humidity, covering leaves with a white coating.
• Anthracnose and bacterial diseases — become active after rain, causing spotting and fruit rot.
• Viral diseases (cucumber mosaic virus, etc.) — transmitted by aphids, which are ubiquitous in open ground.

Among pests, the greatest damage is caused by melon aphids, spider mites (especially in dry, hot weather), whiteflies, and thrips (Котов and Адрицкая, 2016). With high pest numbers, plants weaken and fruit quality drops sharply.

Short fruiting period. In open ground, the harvest season usually lasts 1.5–2 months. With the onset of autumn cooling (temperatures below 12–15°C), growth slows and yield declines. In regions with short summers, a gardener may only get 2–3 waves of fruit, whereas in a greenhouse, this period can be extended into autumn (Ториков and Сычев, 2018).

Bitterness in fruits. Stressful conditions (lack of moisture, sharp temperature fluctuations, nutrient deficiencies) trigger the accumulation of cucurbitacin, the compound that gives cucumbers a bitter taste. This is especially noticeable in dry years. Fortunately, many modern hybrids lack this trait, but older varieties and bee-pollinated forms may become bitter at the slightest stress (Welbaum, 2015).

2.3. How to Choose a Site and Prepare the Soil

2.4. Timing and Planting Methods

2.5. Plant Care in Open Ground

2.6. Growing Features in Different Climatic Zones

• In regions with cold, short summers (Urals, Siberia, Far East) — use only early-maturing varieties (Muromsky, Altaysky ranny, Izyashchny) and be sure to plant 20–30-day-old seedlings in warm beds or ridges with film cover initially. Mulching with black film raises soil temperature by 2–4°C, which is critical for early growth.
• In arid southern regions (Volga region, Caucasus, Central Asia) — the main problems are moisture deficiency and overheating. Here you need drought-tolerant varieties, deep watering (up to 20–30 cm), mandatory mulching, and shading (e.g., planting alongside tall crops—corn, sunflowers) to reduce midday air temperature. Drip irrigation and fertigation significantly increase efficiency.
• In humid climate regions (northwest, Baltic region) — fungal diseases are the main enemies. Here you need varieties with maximum resistance to downy mildew, good ventilation (wide spacing, raised beds), avoiding overhead watering (only at the root), and mandatory preventive fungicide treatments from the 3–4 leaf stage (Welbaum, 2015).

2.7. Recommended Varieties for Open Ground

For northern and temperate regions (early-maturing, cold-hardy):

• Muromsky 36 — an old Russian variety, the earliest (40–45 days from emergence). Small fruits (6–10 cm), excellent for pickling. Yield up to 7 kg/m². Not heat- or drought-tolerant (Лебедева, 1987).
• Altaysky ranny 166 — early-maturing, short-vined, tolerates cold well. Fruits up to 10 cm, for salads. Yield 3–6 kg/m².
• Izyashchny — early-maturing, white-spined, fruits 9–13 cm, resistant to olive spot. Yield up to 6 kg/m².

For central and southern regions (universal, high-yielding):

• Konkurent — bee-pollinated, medium-early, resistant to downy mildew. Fruits up to 12 cm, for pickling.
• Nerosimy 40 — late-maturing, very productive, resistant to low temperatures. Fruits up to 15 cm, for salads.
• Feniks — late-maturing, highly resistant to downy mildew, excellent for southern regions with humid summers.

For southern arid regions:

• Hybrid F1 Kaskad — medium-early, heat- and drought-tolerant, fruits 10–12 cm, universal.
• Hybrid F1 Brigadny — bee-pollinated, high-yielding, resistant to a complex of diseases.

Many parthenocarpic hybrids, recommended for greenhouses, are also suitable for open ground and, with pollination, produce even higher yields, e.g., F1 Zozulya, F1 Connie, F1 Herman.

2.8. Temporary Coverings — the "Golden Mean"

To extend the season and protect against early frosts, many gardeners use temporary film covers (hoops with film or agrospan). These are installed in early spring to warm the soil and plant seedlings 2–3 weeks earlier than usual, and in autumn they extend fruiting by another 2–3 weeks. This simple solution allows yields comparable in timing to greenhouse production, at minimal cost (Лебедева, 1987).

Important: on sunny days, temperatures under film can rise above 35°C, so coverings need regular ventilation by lifting the edges.

2.9. Harvesting and Storage

Cucumbers are harvested regularly (every 1–2 days) at technical maturity, not allowing overgrowth. Delaying harvest reduces the formation of new ovaries and impairs quality. Only healthy, undamaged fruits should be picked.

Harvested cucumbers are stored in a cool place (10–15°C) at high humidity (85–90%) for 3–5 days. For longer storage, use a refrigerator (2–4°C), but no more than 7–10 days, as cucumbers are sensitive to low temperatures and quickly lose turgor (Nonnecke, 1989).

Conclusion

Growing cucumbers in open ground is an accessible and proven method to obtain tasty, aromatic fruits. Success depends on choosing the right variety, timely planting, regular watering, and disease protection. Despite all the risks (weather disasters, pests), open ground remains the main method for most gardeners due to its simplicity and naturalness.

If your region does not offer stable warmth and summers are short, combine open ground with temporary coverings, use early-maturing varieties, and plant seedlings. This way, you can get a harvest no worse than greenhouse-grown, but at lower cost.

3.1. Advantages of Greenhouse Growing

Early and guaranteed harvest. In a greenhouse, seedlings can be planted as early as April (in the central region), when there is still snow outside or the soil has not warmed up. Protection from return frosts and the ability to regulate temperature allow the first fruits to be harvested 40–50 days after planting, 2–4 weeks earlier than in open ground (Котов and Адрицкая, 2016). This is especially valuable in regions with short summers, where every warm day counts.

Long fruiting period. In an unheated greenhouse, cucumbers can bear fruit from May to September–October, depending on the weather. In heated structures with supplementary lighting, year-round cultivation is possible. This allows a stable harvest over many months, which is not possible in open ground (Ториков and Сычев, 2018).

High yield. With intensive technology, a greenhouse produces 3–4 times more fruit per unit area compared to open ground. Parthenocarpic hybrids, with proper training and nutrition, can yield up to 25–30 kg/m² per season (Котов and Адрицкая, 2016). This is achieved through optimal conditions, long fruiting, and the use of vertical trellises, which maximize light and space utilization.

Protection from adverse weather. The greenhouse reliably protects plants from cold winds, hail, prolonged rains, and sharp temperature fluctuations. This is especially important in regions with unstable climates, where summers can be rainy or cool. Fruits remain clean, without soil stains, and have an excellent marketable appearance (Welbaum, 2015).

Control over pests and diseases. In a protected environment, it is much easier to control the spread of infections and insect pests. The use of insect screens on ventilation openings, soil and equipment disinfection, and regular preventive treatments can significantly reduce the risk of disease outbreaks. Additionally, biological protection methods (entomophages, beneficial microorganisms) can be used in greenhouses without risk of being washed away by rain.

Ability to use modern agrotechnical methods. In a greenhouse, drip irrigation, fertigation (applying fertilizers with water), CO₂ enrichment, supplementary lighting, and the use of bumblebees for pollination are highly effective. All these methods increase plant productivity and make the gardener's work easier (Ториков and Сычев, 2018).

3.2. Disadvantages and Risks of a Greenhouse

Capital costs. Building a greenhouse, even a simple film one, requires investment. Polycarbonate and glass structures, automatic ventilation, drip irrigation, and heating systems represent significant investments that pay off only with regular use and high yields.

Risk of overheating. On sunny days, temperatures in a greenhouse can quickly rise to 40–50°C, especially with insufficient ventilation. This is detrimental to cucumbers: at temperatures above 32°C, pollen becomes sterile, flowers drop, and fruit set fails. Therefore, a good ventilation system (windows, automatic openers) is essential for greenhouse cultivation (Лебедева, 1987).

Need for plant training. In a greenhouse, cucumbers are usually grown on vertical trellises, requiring regular tying, pinching of lateral shoots, and removal of old leaves. This is labor-intensive and meticulous work, especially with a large number of plants. Without training, bushes quickly overgrow, shade each other, and yield drops sharply (Котов and Адрицкая, 2016).

Manual pollination or use of parthenocarpics. In a protected environment, bees rarely enter, so for bee-pollinated varieties, manual pollination is necessary—in the morning, pick male flowers and touch them to the stigma of female flowers. This takes time and requires care. An alternative is the use of parthenocarpic hybrids (not requiring pollination) or installing bumblebee hives (also expensive).

Rapid spread of diseases. If an infection source appears in the greenhouse (powdery mildew, fusarium, gray mold), it spreads much faster than in open ground due to high humidity, temperature, and lack of wind. Therefore, prevention is critical: soil and structure disinfection, seed treatment, maintaining an optimal microclimate, and regular ventilation (Welbaum, 2015).

Soil salinization and need for substrate replacement. With intensive use of mineral fertilizers, salts accumulate in the soil, inhibiting the root system. In greenhouses where soil is used for several consecutive years, annual replacement of the top layer (10–15 cm) or use of artificial substrates (hydroponics) is required. This is an additional cost and labor.

Increased watering and nutrition requirements. In a greenhouse, especially with drip irrigation, water and fertilizers must be precisely dosed. Overwatering or moisture deficiency quickly affects plants. Additionally, due to the limited root zone, nutrient reserves deplete faster, so feeding must be done more frequently than in open ground.

3.3. Types of Greenhouses and Their Features

Glazed winter greenhouses. These are permanent structures with glass covering, heating, supplementary lighting, and automated climate control systems. They allow year-round cucumber cultivation but require high construction and operating costs. Rarely found in hobby gardening.

Polycarbonate greenhouses. The most popular type for hobby gardeners. Polycarbonate retains heat well, is durable, transmits light, and is cheaper than glass. In such greenhouses, cucumbers can be grown from early spring to late autumn (with additional heating during cool periods). Polycarbonate provides excellent light transmission but can heat up significantly in summer, so ventilation is essential.

Film greenhouses. The most budget option. Film transmits light well but is less durable and has a shorter lifespan (usually 1–3 seasons). In film greenhouses, maintaining a stable temperature regime is more difficult as the film cools faster at night. However, they are quite suitable for growing cucumbers in spring-summer periods, especially in temperate climates.

Tunnel covers (hoops with film or agrospan). These are the simplest temporary structures, considered an intermediate option between open ground and a full greenhouse. They are used for early planting of seedlings and protection from early frosts. Cucumbers can also be grown in them, but full fruiting is usually shorter than in a permanent greenhouse.

3.4. Greenhouse and Soil Preparation

Sanitary treatment. Before the season, the greenhouse is thoroughly cleaned of plant debris (previous year's leaves, stems) and all surfaces (glass, polycarbonate, frame) are washed with a weak soap solution or specialized disinfectants. This destroys fungal spores and pest eggs that may have survived from the previous year.

Soil disinfection. If the greenhouse has been used for more than one year, the soil must be disinfected. The best method is steaming (flushing with boiling water or hot steam) or using biological products (e.g., Trichodermin, Fitosporin). Industrial greenhouses use chemical sterilization (formalin, metam-sodium) or soil replacement. For the hobby gardener, the simplest method is to annually remove the top layer (10–15 cm) and replace it with fresh soil mix (Ториков and Сычев, 2018).

Soil mix. The ideal greenhouse soil should be loose, moisture-retentive, breathable, and nutritious. Recommended composition: 50% lowland peat, 30% turf soil, 20% humus or compost, with sand or sawdust added for loosening. Per 1 m³ of mix, add 4–5 kg of lime (to neutralize acidity), 1.5–2 kg of superphosphate, and 0.5 kg of potassium salt (Котов and Адрицкая, 2016). Ready-made cucumber soils available at garden centers can also be used.

Biofuel. For early spring cultivation (April–May) in unheated greenhouses, biofuel is often used—fresh manure (horse manure is best as it generates more heat). Manure is placed in a 25–30 cm layer, with fertile soil 20–25 cm thick on top. As manure decomposes, it releases heat, allowing seedlings to be planted 2–3 weeks earlier than without heating (Лебедева, 1987).

3.5. Selecting Varieties and Hybrids for the Greenhouse

For greenhouses, the vast majority of gardeners choose parthenocarpic hybrids. They do not require pollination, which is ideal for protected cultivation, and produce higher, more stable yields. By fruit type, they are divided into:

• Long-fruited (fruit weight 200–500 g, length up to 30–40 cm) — mainly used in salads. Popular hybrids: F1 Zozulya, F1 Courage, F1 Estafeta, F1 Tayga, F1 Olimpiada (Котов and Адрицкая, 2016). They yield up to 25–30 kg/m² in extended cultivation.
• Short-fruited (gherkin-type) — fruits 8–14 cm, universal use (fresh and pickling). Hybrids: F1 Marinda, F1 Herman, F1 Natasha, F1 Connie, F1 Claudia. They are more productive under intensive cultivation and often have combined disease resistance.

When selecting, pay attention to disease resistance (downy mildew, powdery mildew, cucumber mosaic virus, root rots). Modern hybrids can be resistant to 5–7 diseases, significantly simplifying care and reducing the number of treatments.

If you still prefer to use bee-pollinated varieties (for flavor or pickling), you will have to pollinate them manually or place hives in the greenhouse. Additionally, it is necessary to plant pollinator varieties (about 10–15% of total plants) that produce male flowers (Котов and Адрицкая, 2016).

3.6. Planting and Plant Training

3.7. Climate Control

3.8. Nutrition and Fertilization

In a greenhouse, especially with intensive use, plants quickly deplete the soil. Fertilizing is done every 7–10 days, alternating organic and mineral fertilizers.

• First feeding – 2 weeks after planting: nitrogen (20–25 g urea per 10 L) for green mass development.
• At the start of flowering and fruiting: switch to complex fertilizers with a predominance of potassium and phosphorus (e.g., monopotassium phosphate – 10–15 g per 10 L, or Kemira-universal 30 g per 10 L). Organic feedings (cow manure infusion 1:10 or poultry manure 1:20) are done every 2 weeks.
• During mass fruiting: potassium fertilizers (Kalimagnesia, potassium sulfate) and complexes with microelements.

Dosage: use 5–10 L of solution per 1 m² of bed. Fertilize only on moist soil to avoid root burn. Foliar feeding (spraying leaves) with microelements is beneficial when boron, manganese, or zinc is deficient (Котов and Адрицкая, 2016).

3.9. Disease and Pest Control in the Greenhouse

Prevention is the foundation of protection in protected cultivation. Key measures:

• Soil and structure disinfection before planting.
• Use of resistant hybrids.
• Optimal microclimate – timely ventilation, humidity control.
• Regular inspection – removal of first affected leaves and ovaries.
• Biological products – Trichodermin, Fitosporin, Planriz for root rots; Baktofit, Fitolavin against bacterial diseases.
• When diseases appear – use approved fungicides (copper-based products, Previcur, Ridomil Gold, Skor, Topaz). Strictly observe pre-harvest intervals.
• Against pests (whitefly, aphids, spider mites) – insecticides (Aktara, Actellik, Vertimek) and biological methods (entomophages – predatory mites, Encarsia against whitefly).

In a greenhouse, use only products approved for protected cultivation (not all have such registration). Always read the label (Welbaum, 2015).

3.10. Harvesting

In a greenhouse, harvest even more frequently than in open ground – every 1–2 days during mass fruiting. This stimulates the formation of new ovaries and maintains high productivity. Cut fruits with scissors or a knife, leaving a small peduncle to avoid damaging the vine. Harvest in the morning when fruits are most turgid and store better.

Greenhouse cucumbers, especially parthenocarpic ones, have thin tender skin and quickly lose moisture. Store them in the refrigerator in a perforated plastic bag, at 10–12°C and 90–95% humidity, for no more than 5–7 days. Do not place them near apples, tomatoes, or bananas – the ethylene they emit accelerates fruit yellowing (Nonnecke, 1989).

Conclusion

Greenhouse cucumber cultivation is the path to maximum productivity and control over the process. It requires more attention, knowledge, and initial investment but pays off with early, abundant, and long-lasting harvests. A greenhouse allows fresh cucumbers from spring to late autumn even in regions with unstable climates. Key success factors are choosing parthenocarpic hybrids, proper plant training, maintaining an optimal microclimate, and disease prevention.

If you are willing to devote time to your plants and monitor their every "breath," the greenhouse will be your best ally. If you prefer minimal care and are not chasing record early harvests, open ground will also give you a decent yield – but we discussed that in detail in the previous chapter.

4.1. Temperature Regime

For cucumber, temperature is a critical factor determining growth rate, flowering, fruit set, and fruit quality.

Optimal values overall:

• Seed germination: 25–30°C (at 12–13°C, germination practically stops) (Котов and Адрицкая, 2016).
• Growth and development: daytime 22–28°C, nighttime 16–18°C.
• Below 15°C, growth slows; above 32–35°C, pollen becomes sterile, flowers and ovaries drop (Welbaum, 2015).

In open ground, the gardener has almost no influence on temperature. They can only choose planting dates and use temporary coverings (film, agrospan). Successful cultivation requires stable warm weather without sharp fluctuations. Main risks:

• Spring frosts – even a brief drop to -1…-2°C is fatal for seedlings and young plants.
• Cold nights (below 10–12°C) – delay development, weaken plants, promote root rots.
• Extended heat (above 30°C) – without watering and natural cooling, reduces fruit set.

In a greenhouse, temperature can be regulated:

• In spring, the greenhouse allows planting seedlings 3–4 weeks earlier than open ground by accumulating solar heat and (if necessary) heating.
• On hot days, overheating is a risk. Above 30–32°C, active ventilation and shading are required; otherwise, plants lose their fruiting capacity.
• Nighttime temperatures in a greenhouse are always higher than outside, promoting continuous growth (Котов and Адрицкая, 2016).

Conclusion for the gardener: In open ground, you adapt to the weather. In a greenhouse, you create the weather. For greenhouses, thermometers and ventilation systems are mandatory; in open ground, the key is choosing correct planting dates and varieties.

4.2. Air Humidity

Cucumber is a tropical humid-climate plant, requiring high relative air humidity – 85–90% during active growth and fruiting.

In open ground, humidity is determined by the weather and cannot be controlled:

• During rainy periods, humidity can reach 95–100%, creating ideal conditions for downy mildew, anthracnose, and bacterial diseases (Quesada-Ocampo, 2022).
• In dry hot weather, humidity drops to 40–50%, stressing plants, impairing pollination, and promoting spider mites.
• The gardener can only indirectly influence the microclimate: mulching, spraying paths (on small plots), and choosing the right watering time.

In a greenhouse, humidity is controlled through watering and ventilation:

• In a closed greenhouse without ventilation, humidity easily rises to 95–100%, which, combined with low temperatures (night, early spring), leads to condensation on leaves and fruits, promoting gray mold and ascochyta (Welbaum, 2015).
• With intensive ventilation in hot weather, humidity can drop below 60%, which is also undesirable – turgor decreases, fruit set worsens.
• Optimal strategy: maintain humidity at 75–85% through morning watering (water evaporates during the day) and daytime ventilation. In warm weather, spraying paths is beneficial (Котов and Адрицкая, 2016).

Conclusion for the gardener: In open ground, you accept humidity as given and choose disease-resistant varieties. In a greenhouse, you manage humidity, but this requires constant monitoring – too dry or too wet is equally harmful.

4.3. Watering and Soil Moisture

Cucumber consumes enormous amounts of water: at a yield of 30 t/ha, plants transpire and accumulate up to 5600 m³ of water per season (Nonnecke, 1989). Optimal soil moisture is 70–80% of field capacity.

In open ground, watering depends on the weather:

• In dry hot weather, water frequently (daily or every other day), using 10–15 L/m². During rainy periods, reduce or stop watering.
• Main problems: uneven wetting (drying → flooding), leading to fruit cracking; inability to precisely dose water; soil cooling when watering with cold well water (Welbaum, 2015).
• Mulching and drip lines in open ground help smooth out fluctuations but remain costly.

In a greenhouse, watering can be precisely regulated:

• Drip irrigation is most effective, delivering water directly to the root zone in small amounts, maintaining stable moisture.
• Water use in greenhouses is lower as there is no loss from evaporation in row spaces and wind. At peak fruiting, one plant may consume 2–3 L of water per day (Ториков and Сычев, 2018).
• A strict rule: water only with warm water (22–25°C). Cold water in a greenhouse is especially dangerous, as it sharply reduces root zone temperature.
• In a greenhouse, do not overwater – excess moisture without drainage leads to salinization, root rots, and Pythium development (Котов and Адрицкая, 2016).

Conclusion for the gardener: In open ground, watering is "fighting the weather"; in a greenhouse, it is a precise growth management tool. Drip irrigation in greenhouses is practically essential for stable yields.

4.4. Nutrition and Fertilizers

Cucumber is a crop with intensive nutrient uptake. From the start of flowering to mass fruiting, plants absorb about 80% of all nutrients. For 1 ton of fruit, approximately 3–4 kg of nitrogen, 1.5–2 kg of phosphorus, and 4–5 kg of potassium are required (Котов and Адрицкая, 2016).

In open ground, main fertilizers are applied in autumn and spring (humus, compost, superphosphate, potassium salts). During the season, 2–4 root feedings are done. Problems:

• In rainy years, nitrogen and potassium are quickly leached from the root zone, and plants may suffer deficiencies.
• Difficult to precisely dose fertilizers per plant – often applied "by eye."
• Applying fertilizers to dry soil is ineffective and can cause root burn.

In a greenhouse, nutrition can be precisely regulated through fertigation – applying fertilizers with irrigation water through a drip system:

• Fertilizers are applied daily or every other day in small doses, precisely matching the plant's growth stage (growth → flowering → fruiting).
• At the beginning of vegetation – nitrogen predominance for leaf mass development. During flowering and fruiting – increased potassium and phosphorus for better fruit set and quality (Welbaum, 2015).
• Foliar feeding (by leaf) with microelements (boron, manganese, zinc) is possible – in greenhouses, they are quickly absorbed.
• However, greenhouse soil with intensive fertigation salinizes faster, so regular monitoring of soil solution electrical conductivity and periodic leaching are necessary (Ториков and Сычев, 2018).

Conclusion for the gardener: In open ground, basic feedings according to a standard scheme are sufficient. In a greenhouse, nutrition becomes part of daily care – it is flexible, precise, and allows you to "tune" plants to the desired load.

4.5. Ventilation

Ventilation is a factor that requires almost no attention in open ground (natural air circulation is always sufficient), but becomes critical in a greenhouse.

In open ground, fresh air circulates freely, cooling plants in hot weather and promoting rapid drying of leaves after rain. This naturally reduces the risk of many fungal diseases. Wind also helps harden plants and strengthen stems.

In a greenhouse, without ventilation, air stagnates, heats up, and becomes humid, creating ideal conditions for fungal infections. Main ventilation tasks in a greenhouse:

1. Reduce temperature on sunny days (prevent overheating above 30–32°C).

2. Remove excess moisture (especially after watering and at night, to avoid condensation on plants).

3. Provide CO₂ supply for photosynthesis (in a closed greenhouse, CO₂ levels drop rapidly, slowing growth) (Котов and Адрицкая, 2016).

Practical recommendations for the greenhouse:

• Open vents daily in the morning, even on cloudy days.
• In hot weather – keep vents open all day. If there are doors on both sides, create a draft.
• Use automatic thermal openers for vents – they regulate opening based on temperature.
• During extreme heat (above 35°C), use shading nets or whitewash polycarbonate/glass.

Conclusion for the gardener: If in open ground ventilation is nature's gift, in a greenhouse it is your responsibility. Without regular ventilation, even the best variety will not yield a harvest.

4.6. Lighting

Cucumber is a light-loving plant, but it is more shade-tolerant than tomatoes or peppers. However, insufficient light severely reduces productivity.

In open ground, lighting is maximally natural, but its intensity depends on weather and geographic latitude:

• In cloudy summers, plants stretch, internodes lengthen, and fewer ovaries form.
• In southern regions, too much sun is also harmful – combined with heat, it causes overheating and leaf scorch.

In a greenhouse, lighting is often a limiting factor:

• Light-transmitting materials (glass, polycarbonate, film) block 10–20% of light, especially when dirty.
• In winter and early spring, daylight is short, and without supplementary lighting, plants stretch, and flowering and fruiting are delayed (Ториков and Сычев, 2018).
• For early spring cultivation (February–March), phytolamps are essential – sodium or LED lamps providing 12–14 hours of daylight.
• In summer, there is usually enough light in the greenhouse, but due to overcrowding (dense planting, unremoved old leaves), lower tiers may be shaded, reducing yield.

Recommendations:

• In the greenhouse, thin out plantings and regularly remove old leaves (especially in the lower part) to allow light to reach all ovaries.
• Orient beds north–south for uniform lighting.
• Use parthenocarpic hybrids adapted to low light (e.g., F1 Zozulya, F1 Courage, F1 Estafeta) – they produce good yields even in short-day conditions (Котов and Адрицкая, 2016).

Conclusion for the gardener: In open ground, light is a free resource, and you only need to choose the right location for the bed. In a greenhouse, light must be "saved" (regular cleaning of coverings, proper plant training) and, when necessary, "supplemented" (supplementary lighting early in the season).

4.7. Summary Table: Growing Condition Requirements

Overall Conclusion

Cucumber remains cucumber – its needs for warmth, moisture, nutrition, and light are universal. However, the ways to meet these needs differ radically between open ground and a greenhouse.

• In open ground, you work with what nature provides: your task is to choose the right timing, varieties, and adapt care to the specific season. This is a path of greater flexibility, lower costs, but greater dependence on weather whims.
• In a greenhouse, you create an artificial microclimate, taking responsibility for every factor. This is a path of maximum control, high yields, but requires knowledge, time, and discipline.

Understanding these differences helps not only choose the right cultivation method but also avoid disappointment. Growing in open ground, do not expect greenhouse yields in a cold rainy summer. And in a greenhouse, do not expect plants to "manage on their own" without your regular care.

5.1. Bee-Pollinated Varieties

These are the classic cucumbers we have known since childhood. On a single plant, both male (empty flowers) and female flowers form. For fruit to develop, an insect (bee, bumblebee) must transfer pollen from a male flower to a female flower. The female flower has a noticeable small ovary – the future cucumber – while male flowers are usually in small clusters and have no ovary (Nonnecke, 1989).

Main characteristics:

• Require pollinating insects for fruit set.
• Flowering and fruiting directly depend on weather: during rainy or cold days, bee activity is limited, and fewer ovaries form.
• Usually have a pronounced "cucumber" aroma and dense, crunchy flesh.
• Often better suited for pickling and preserving (especially older varieties with black spines).
• In greenhouses without insects, they require manual pollination (Welbaum, 2015).

Examples of bee-pollinated varieties for open ground (Лебедева, 1987):

• Muromsky 36 – an old early-maturing variety (40–45 days). Small fruits (4–6 cm), black-spined, excellent for pickling. Not heat- or drought-tolerant. Good for northern regions with short summers.
• Vyaznikovsky 37 – early-maturing, medium-growing. Fruits 9–11 cm, black-spined, pickling type. Relatively drought- and cold-tolerant.
• Izyashchny – early-maturing, salad type. Fruits 9–13 cm, white-spined, resistant to olive spot. Good transportability.
• Konkurent – medium-early, high-yielding, resistant to downy mildew. Fruits 10–12 cm, pickling type. One of the best for the central region.
• Nerosimy 40 – late-maturing, high-yielding, resistant to low temperatures. Fruits 12–15 cm, salad type. Suitable for northwestern regions.
• Feniks – late-maturing, highly resistant to downy mildew. An excellent choice for southern regions with humid summers, where downy mildew is a serious problem.

5.2. Parthenocarpic Hybrids

These are first-generation hybrids (F1) that produce fruit without pollination. In female flowers, the ovary grows on its own, without pollen participation. Most such hybrids have all female flowers, and male flowers are absent or appear only under stress (e.g., low temperature or nutrient deficiency). Parthenocarpy is not genetic engineering but the result of classical breeding, fixed in hybrids (Котов and Адрицкая, 2016).

Main characteristics:

• Do not require pollination – ideal for greenhouses and protected cultivation.
• Produce higher and more stable yields, as they do not depend on weather and insect presence.
• Fruits are usually seedless or with rudimentary (underdeveloped) seeds.
• Tender flesh, thin skin, making them excellent for salads, but for pickling, choose special hybrids (with dense flesh).
• Many modern parthenocarpics have combined resistance to 5–7 diseases (Welbaum, 2015).

By fruiting type, parthenocarpics are divided into:

• Long-fruited (fruit length 25–40 cm, weight 200–500 g) – mainly salad types, for fresh consumption. Examples: F1 Zozulya, F1 Courage, F1 Estafeta, F1 Tayga, F1 Olimpiada, F1 Arina, F1 Stella.
• Short-fruited (gherkin type) – fruits 8–14 cm, universal (fresh and pickling). Examples: F1 Marinda, F1 Herman, F1 Natasha, F1 Connie, F1 Claudia, F1 Chris, F1 Pasadena.
• Medium-fruited – intermediate, fruits 15–20 cm. Examples: F1 Forward, F1 Mahaon.

Popular parthenocarpic hybrids for different conditions (Котов and Адрицкая, 2016):

• F1 Zozulya – one of the most famous, early-maturing (45–50 days), long-fruited (20–25 cm), salad type. Resistant to root rots. Excellent choice for greenhouses in the central region.
• F1 Courage – early-maturing, gherkin type, fruits up to 12 cm. Very productive, resistant to powdery mildew and cucumber mosaic virus. Excellent fruit set under any conditions.
• F1 Herman – ultra-early (38–40 days), gherkin type, fruits up to 10 cm. Cluster flowering type (4–6 ovaries per node). Very popular among gardeners for stable yields.
• F1 Marinda – medium-early, gherkin type. Resistant to downy mildew and viruses. Suitable for both greenhouses and open ground.
• F1 Estafeta – long-fruited (30–35 cm), late-maturing, very productive (up to 28 kg/m²). Used in commercial greenhouses.
• F1 Arina – medium-early, long-fruited (25–30 cm), disease-resistant. Good for film greenhouses.

5.3. Universal Varieties and Hybrids (Facultative Parthenocarpics)

These are hybrids that can produce fruit both with and without pollination. With insects present, yield is higher, but even without pollination (e.g., in a greenhouse without bees), they produce a certain number of fruits. This is a "fallback" option for gardeners unsure about the weather or pollination opportunities (Nonnecke, 1989).

Main characteristics:

• Flexibility: suitable for both open ground and greenhouses.
• Yield slightly lower than pure parthenocarpics in greenhouses but higher than bee-pollinated varieties in bad weather.
• Good fruit set under different conditions.
• Often have moderate disease resistance.

Examples: F1 Movir 1, F1 Aprelsky, F1 Kukushka, and some older varieties (e.g., Altaysky ranny 166 – although it is bee-pollinated, it gives some yield when insects are scarce).

5.4. Choosing a Variety by Maturity Date

Depending on the region and goals, it is important to choose the right maturity date:

• Early-maturing (35–45 days from emergence to first harvest) – ideal for regions with short summers (Urals, Siberia, northern areas). Produce quickly, ripen before autumn cold. Examples: Muromsky 36, Altaysky ranny 166, F1 Herman, F1 Zozulya.
• Medium-maturing (45–55 days) – main choice for the central region. Give a longer harvest period and higher yield. Examples: Konkurent, Vyaznikovsky 37, F1 Marinda, F1 Connie.
• Late-maturing (more than 55 days) – for southern regions with long warm seasons. Give maximum yield, often resistant to diseases typical of the second half of summer (downy mildew, powdery mildew). Examples: Nerosimy 40, Feniks, F1 Estafeta.

5.5. Choosing a Variety by Purpose

If you plan to use cucumbers mainly for preserving (pickling, marinating), pay attention to pickling varieties. They have dense, crunchy flesh, thin skin, and absorb brine well. Usually these are black-spined varieties (spines on fruits are black or dark, not white). Examples: Muromsky 36, Vyaznikovsky 37, Konkurent, Rzhavsky mestny (Лебедева, 1987).

For salads and fresh consumption, choose white-spined varieties or parthenocarpics with tender thin skin. Examples: Izyashchny, Altaysky ranny 166, Nerosimy 40, F1 Zozulya, F1 Courage.

Universal varieties (e.g., F1 Marinda, F1 Herman) are good in both salads and pickling, but for brine, they are slightly inferior to specialized pickling varieties.

5.6. Disease Resistance – Key Criterion for Open Ground

In open ground, cucumbers are much more often affected by diseases than in greenhouses. Therefore, when choosing a variety for open ground, pay attention to resistance to:

• Downy mildew (peronospora) – the most dangerous disease in rainy summers. Affects leaves, reducing photosynthesis and yield. Resistant varieties: Feniks, Konkurent, F1 Marinda, F1 Arina.
• Powdery mildew – appears in hot dry weather. Resistance is present in many modern hybrids: F1 Courage, F1 Herman, F1 Natasha.
• Viruses (cucumber mosaic, watermelon mosaic) – transmitted by aphids. Resistance is important in regions with high aphid populations. Resistant hybrids: F1 Brigadny, F1 Rodnichok, F1 Kaskad (Котов and Адрицкая, 2016).

On seed packets, disease resistance is usually indicated by abbreviations (e.g., CMV – cucumber mosaic virus, DM – downy mildew, PM – powdery mildew, etc.).

5.7. Variety Selection Table by Conditions

5.8. Important Note on Seeds

Modern hybrids (marked F1) are the result of crossing two specially selected parental lines. They produce higher and more stable yields than varieties (non-hybrids), but their seeds cannot be saved for the next year – in the second generation, they "split" into parental forms and lose valuable traits. Therefore, for hybrids, you need to buy new seeds each year.

Varieties (without F1 marking) can be propagated from your own seeds, but they are less productive and often less disease-resistant (Nonnecke, 1989).

Conclusion

Choosing a variety is not a matter of personal taste but a strategic decision that determines your success.

• For open ground, choose varieties and hybrids resistant to local diseases, with suitable maturity dates and pollination type. Bee-pollinated varieties are good if you have many bees and stable weather. Parthenocarpics – if summers are unpredictable or you want a guaranteed harvest.
• For greenhouses, unequivocally choose parthenocarpic hybrids. They do not require pollination, give maximum yields, and most are disease-resistant. Pay attention to the fruiting type (gherkin or long-fruited) depending on your goals (pickling or salad).

And perhaps the most important advice: do not be afraid to experiment. Plant 2–3 different varieties or hybrids in one season – this will help you understand what works best for your site, soil, and microclimate.

6.1. Brief Summary: Open Ground vs. Greenhouse

Before moving on to specific scenarios, let's briefly recap the key differences:

6.2. Selection Scenarios: Decision-Making Table

Use this table as a decision-making tool. Find your scenario and see what specialists recommend.

6.3. What to Choose if the Climate Is Unstable?

In regions with changeable climates (frequent rains, sharp temperature fluctuations, cold nights even in June), a greenhouse provides an advantage. However, if building a permanent greenhouse is impossible, consider temporary coverings – hoops with non-woven material (agrospan, spunbond) or film. They protect against frost, reduce the impact of cold winds and rain, and are inexpensive and easy to install. This is the "golden mean" for many gardeners, especially beginners (Лебедева, 1987).

6.4. If You Already Have a Greenhouse: You Don't Have to Use It Only for Cucumbers

A greenhouse is a universal tool. You can grow seedlings for open ground (tomatoes, peppers, cabbage) in it and plant cucumbers in open ground. Or vice versa: early spring, plant cucumbers in the greenhouse for an ultra-early harvest, and in summer, when weather stabilizes, move them to open ground, freeing the greenhouse for tomatoes or peppers. This approach allows efficient use of the greenhouse throughout the season.

6.5. Common Mistakes When Choosing

1. Choosing a variety without considering the growing method. For example, planting bee-pollinated varieties in a greenhouse without insects will certainly lead to empty flowers.

2. Ignoring climatic features. In a cold region, a greenhouse is not a "luxury" but a necessity. In a hot region, a greenhouse without ventilation and shading is a "trap" for plants.

3. Overestimating your capabilities. If you do not have time for daily care and monitoring, a greenhouse can become a source of disappointment. Cucumbers are a plant that "does not forgive" missed waterings and ventilation on hot days.

4. Choosing the cheapest option. Saving on greenhouse quality (thin polycarbonate, weak frame, lack of vents) often leads to additional expenses later.

5. Ignoring crop rotation in the greenhouse. Planting cucumbers in the same spot in the greenhouse every year leads to disease accumulation and soil salinization (Welbaum, 2015).

6.6. Step-by-Step Decision Algorithm

To make a final decision, follow this simple algorithm:

Step 1. Assess your region's climate.

• Average frost-free period: more than 120 days? – open ground is possible. Less than 100 days? – greenhouse is mandatory.
• Average summer temperatures: above 30°C often? – open ground makes it easier to avoid overheating.
• Frequent rains and fog? – a greenhouse will protect against diseases.

Step 2. Define your goals.

• For family (a few plants) – open ground.
• For maximum yield or sale – greenhouse.
• For early harvest – greenhouse or temporary coverings.

Step 3. Assess resources.

• Budget: enough for a greenhouse and equipment?
• Time: ready to devote time to plants daily?
• Plot area: is there space for a greenhouse?

Step 4. Select varieties for the chosen method.

• Open ground: disease-resistant, early-maturing, bee-pollinated or parthenocarpic.
• Greenhouse: parthenocarpic, disease-resistant, with long fruiting.

Step 5. Start small (if unsure).

• Plant some plants in open ground and some under temporary coverings. Based on the season's results, you will understand what works best for your conditions and care style.

6.7. Practical Examples

Situation A. A gardener from the Moscow region, 6 dacha, visits only on weekends. Chose open ground but with straw mulching and drip irrigation. Planted early-maturing hybrids F1 Herman and F1 Marinda. Started harvesting in late June, fruiting continued until mid-August. Yield was enough for the family and several jars of pickles.

Situation B. A gardener from Krasnodar Krai, very hot summers. Tried growing cucumbers in a polycarbonate greenhouse – without ventilation, plants burned within a week. The next year, planted in open ground on the south side, used drip irrigation and mulching. Variety – Konkurent (heat- and disease-resistant). Harvest was abundant and tasty.

Situation C. A farmer from Leningrad Oblast built a polycarbonate greenhouse with automatic ventilation and drip irrigation. Grows parthenocarpic hybrid F1 Estafeta. First harvest in late May, fruiting continues until October. Output – 28 kg/m². The greenhouse pays for itself in 2 seasons.

Final Conclusion

The choice between open ground and a greenhouse is not a competition of "which is better." It is a matter of fitting your conditions, goals, and capabilities.

• Open ground – is classic, accessible, natural flavor, and minimal costs. It is ideal for gardeners with warm stable summers, limited budgets, or lack of time for daily care.
• A greenhouse – is control, stability, high yields, and a long season. It justifies itself in regions with unstable climates, for early production, and when wanting to maximize yield from a small area.

And remember: even if you choose open ground, you can always use temporary coverings (hoops, agrospan) – this improves results almost like a greenhouse, but without capital costs. And if you already have a greenhouse, try combining: plant only some plants in it to extend the season, and the main crop in open ground for rich flavor and ease of care.

Ultimately, the best teacher is experience. Try, make mistakes, draw conclusions – and with each season, your harvest will get better.

7.1. Mistakes in Site Selection and Soil Preparation

7.2. Mistakes in Variety Selection and Seed Preparation

7.3. Mistakes in Planting and Training

7.4. Mistakes in Watering

7.5. Mistakes in Fertilization

7.6. Greenhouse-Specific Mistakes

7.7. Mistakes in Harvesting

7.8. Mistakes in Disease and Pest Control

7.9. Complex Mistakes Leading to Fruit Bitterness

Bitterness in cucumbers is due to cucurbitacin accumulation. It appears under any stress:

• Moisture deficiency or, conversely, water stagnation.
• Sharp temperature fluctuations (cold nights and hot days).
• Potassium and calcium deficiency.
• Root damage (by pests, during cultivation).

How to avoid: Provide plants with stable conditions: regular watering with warm water, balanced nutrition, protection from overheating and frost. Choose varieties and hybrids genetically free of bitterness (they lack the cucurbitacin gene) – most modern parthenocarpic hybrids "do not become bitter" under any conditions (Nonnecke, 1989).

Final Checklist: What to Check Before the Season

To avoid repeating others' mistakes, use this brief checklist:

☐ Site selection: do not plant in the same place for 2 consecutive years; choose a sunny, wind-protected site.

☐ Soil: pH 6.0–6.5, loose, well-drained, with organic matter incorporated.

☐ Seeds: no older than 3–4 years, treated against diseases.

☐ Variety: matches your growing method (open ground/greenhouse) and goals (salad/pickling).

☐ Watering: only warm water, regular, without overwatering or drying out.

☐ Fertilizing: balanced, with potassium predominating during fruiting.

☐ Training: regular removal of suckers (in greenhouse) and old leaves.

☐ Ventilation (greenhouse): essential on hot days, automatic thermal openers are a great help.

☐ Protection: preventive treatments with biological products, alternation of chemical agents.

☐ Harvesting: regular (every 1–2 days), careful, without damaging vines.

Following these simple rules and analyzing your experience, you will achieve increasingly stable and abundant harvests with each season, even in less-than-ideal conditions.

Conclusion

Cucumber is a rewarding crop. With proper care, it responds with rapid growth, abundant flowering, and continuous fruiting. But it "forgives" mistakes less than many other vegetables – its tropical nature demands stability and attention.

We have come a long way: from understanding biological features to choosing a growing method and variety, from practical care advice to analyzing typical mistakes. Now you have all the necessary information to make a balanced decision and grow a worthy harvest – whether in open ground or in a greenhouse, for your family or for sale.

Remember: there is no single correct method. What works perfectly for your neighbor in a mild climate region may fail you in harsher conditions. Observe, experiment, adapt advice to your soil and your microclimate. And may your cucumber season be successful!