Preparing the soil

1.1. Looseness and Air Permeability: “Breathable” Soil for “Underground Shoots”

Perhaps the main requirement of potato for soil is looseness. Potato tubers are not roots but modified underground stems—stolons—that thicken at the ends (Svaider, 1992). For these stems and the tubers themselves to grow and increase in size, the soil must be light and exert no pressure on them.

Why is this important?

• Root and tuber respiration: Like all living organisms, roots and tubers need oxygen for respiration. In dense, waterlogged, or crusting soil, there is little oxygen, which can lead to oxygen starvation, rotting, and disease development (De Jong et al., 2011).
• Easy growth: In loose soil, stolons can spread more easily sideways, and tubers can fill out without encountering dense lumps of earth that could deform them or halt growth.
• Soil structure: Ideal soil is neither dust nor mud. It has a fine crumbly structure with numerous pores filled with air. In such an environment, the root system performs best.

How to check and achieve looseness?

• “Problem” soils: On heavy clay soils that tend to form crusts and compact, potatoes grow poorly, and tubers often become misshapen (De Jong et al., 2011). Such soils require especially careful preparation, including the addition of sand and large amounts of organic matter.
• Ideal option: Sandy loams, loams, or cultivated peat soils are considered ideal. They are naturally loose enough, well aerated, and permeable to water (Pavek, 2014; Welbaum, 2015).

1.2. Water-Holding Capacity and Drainage: The Golden Mean Between Drought and Swamp

Potatoes have high water requirements, especially during budding and flowering when active tuber formation occurs (Balashev and Zeman, 1981). However, they absolutely cannot tolerate stagnant water around the roots.

Why is this important?

• Proper water balance: The soil must both retain moisture well during dry periods and quickly drain excess water during rainy spells. The ability of soil to retain moisture is called water-holding capacity.
• Danger of overwatering: When there is excess water, soil pores fill with water, displacing oxygen. Roots begin to suffocate, slowing growth and potentially leading to root rots and plant death. Moreover, waterlogged soils are an ideal environment for the development of many diseases, such as late blight (Navarre and Pavek, 2014).
• Drainage: This is why drainage is so important. On plots with a high water table or in lowlands where water accumulates, potato plantings are doomed to failure.

How to find the balance?

• For sandy loam soils: They retain moisture poorly, so they require more frequent watering and the mandatory addition of organic matter, which acts like a sponge, holding water and nutrients in the root zone.
• For clay and heavy soils: The main task is to improve drainage. This is achieved by deep digging, adding loosening materials (sand, humus, compost), and, if necessary, creating ridges or raised beds to divert excess moisture (De Jong et al., 2011).

1.3. Optimal Acidity (pH): Tasty Food for Plants

Soil acidity (pH) is a chemical indicator that affects which nutrients become available to plants. For potatoes, this is one of the key parameters.

Why is this important?

• Nutrient availability: At pH 5.5–6.5, most of the nutrients required by potatoes (nitrogen, phosphorus, potassium, calcium, magnesium) are in readily available forms (De Jong et al., 2011).
• Scab control: The main reason to maintain a slightly acidic reaction (pH 5.0–5.5) is a natural way to control common scab—a widespread disease that spoils the appearance of tubers, making them unsuitable for sale and storage. The causal agent of scab (Streptomyces scabies) actively multiplies in neutral and alkaline environments (Welbaum, 2015).
• Lowering pH: If your soil is neutral (pH 7.0) or alkaline, lowering it specifically for potatoes to an acidic level is difficult and expensive. In that case, it is simpler to choose scab-resistant varieties (De Jong et al., 2011).

How to determine and adjust pH?

• Testing: You will need either litmus paper (available at garden stores) or a laboratory soil analysis through an agronomic service. This will give you the exact pH value.
• Raising pH (deacidification): If the soil is too acidic (pH < 5.0), it is limed by adding dolomite flour, chalk, or lime. This is usually done in autumn under digging.
• Lowering pH: To lower pH (acidification), you can use sulfur or apply physiologically acidic fertilizers, such as ammonium sulfate. However, this process is slow.

1.4. Soil Structure and Organic Matter: The Basis of Everything

Soil structure and organic matter content combine all the previous points. Organic matter is a “magic wand” for any soil.

Why is this important?

• Improving structure: Adding organic matter (compost, humus, green manures) binds sand particles and loosens clay, creating that ideal crumbly structure (Tarakanov and Mukhin, 2003).
• Moisture and nutrition: Organic substances act like a sponge, holding moisture and serving as a “home” for beneficial soil bacteria that convert them into plant-available nutrients.
• “Cushion” for tubers: Loose, well-structured soil rich in organic matter allows tubers to expand easily without experiencing water or nutrient deficits, directly influencing their size and shape.

How to improve structure?

Add organic matter: Annual application of well-rotted manure, compost, or green manure crops (mustard, phacelia, winter rye) is the best way to maintain fertility and soil health (De Jong et al., 2011).

Conclusion for Chapter 1:

Ideal soil for potatoes is loose, well-drained loam or sandy loam with a pH of 5.0–6.5, rich in organic matter. Providing these conditions is the first and most important step toward a healthy and abundant harvest.

2.1. Light Exposure: “Potatoes Love Sunlight”

This rule has no exceptions. Potato is a light-loving crop (Torikov and Sychev, 2018). Its foliage must actively photosynthesize to “feed” the growing tubers. The more light the leaves receive, the more carbohydrates (starch) they produce and send to the tubers.

Why is this important?

• High yield: To set many tubers and ensure their active growth, the plant needs vigorous, healthy foliage. Light is the main source of energy for its growth.
• Early harvest: On well-lit plots, the soil warms up faster, and seedlings emerge earlier.

Practical tips:

• Open area: Choose the sunniest spot on your plot. Potatoes should not be shaded by trees, buildings, or tall crops.
• Bed orientation: If possible, arrange potato rows from north to south. This way, plants will receive maximum sunlight throughout the day.

2.2. Water Stagnation and Topography: “Where It’s Dry, There’s Harvest”

We already discussed that potatoes do not tolerate water stagnation around the roots. Therefore, choosing the right topography is a matter of life and death for your harvest.

Why is this important?

• Lowlands are a risk zone: In hollows, depressions, and areas with a high water table, rainwater and meltwater accumulate. The soil there stays wet for a long time, leading to rotting of seed tubers, slow growth, and disease development (De Jong et al., 2011; Pavek, 2014).
• Elevations are a priority: If your plot is in a lowland, the best thing to do is to create raised beds or ridges. Planting on ridges raises the root system and tubers above the main soil level, ensuring good drainage and rapid warming (Svaider, 1992; Welbaum, 2015).

Practical tips:

• Assess the site: In spring, after snowmelt or heavy rains, notice where water stagnates longest on your plot. Avoid those spots for planting potatoes.
• Artificial drainage: If water stagnation is a serious problem (e.g., your plot is a former swamp or river floodplain), consider installing a drainage system.
• Raised beds: This is the simplest and most effective method for most gardeners. Beds 20–30 cm high not only provide drainage but also allow the soil to warm up faster in spring.

2.3. Crop Rotation and Predecessors: “The Law of the Garden”

This is one of the most important and, unfortunately, often ignored points. Many gardeners, having small plots, plant potatoes year after year in the same place. This is a direct path to diseases and variety degeneration.

Why is this important?

• Accumulation of diseases and pests: Potatoes are affected by many specific diseases (late blight, scab, various rots) and pests (Colorado potato beetle, wireworms). If planted continuously in the same place, the pathogens and pest larvae accumulate in the soil, making them increasingly difficult to control each year (Welbaum, 2015).
• Soil depletion: Potatoes are “gluttonous” crops, removing large amounts of potassium and nitrogen from the soil. Continuous cultivation in one place depletes reserves of these elements and disrupts nutrient balance (Balashev and Zeman, 1981).

Key rule: do not plant potatoes after solanaceous crops.

“Forbidden” predecessors: Potatoes, tomatoes, eggplants, peppers, tomatillos, and other crops from the Solanaceae family suffer from the same diseases and pests. Planting potatoes after them is categorically not recommended. The ideal break before returning potatoes to the same spot is 3–4 years (De Jong et al., 2011).

Best predecessors for potatoes:

• Legumes (peas, beans, broad beans, lupine): Enrich the soil with nitrogen, which nodule bacteria “extract” from the air. This is an excellent “breakfast” for future potatoes.
• Brassicas (cabbage, radish, turnip): Have no common diseases with solanaceous plants and loosen the soil well with their root systems.
• Cucurbits (cucumber, zucchini, pumpkin): Also considered good predecessors.
• Green manures: These are plants specifically sown for subsequent incorporation into the soil (mustard, phacelia, winter rye, rapeseed). This is the best way to restore soil fertility and improve its health. Green manures can be sown immediately after harvesting an early crop.

Predecessor summary table:

Conclusion for Chapter 2:

Choosing the right site for potatoes is the difference between a “bountiful” and a “hungry” year. Give preference to sunny, well-drained areas (or create good drainage with raised beds). And most importantly, follow crop rotation and do not plant potatoes after their “relatives” from the Solanaceae family. Remember: healthy soil is not only the right composition but also the right history of its use.

3.1. Why Is Crop Rotation So Important?

The main reason is biological balance. In nature, plants generally do not grow as monocultures in one place. They coexist and alternate. This prevents pests and diseases that specialize in one plant species from multiplying to catastrophic levels. In the garden, we must artificially maintain this balance.

What happens when crop rotation is violated:

• Accumulation of pathogens and pests: Fungal disease spores (late blight, fusarium, rhizoctonia), bacterial rots, and insect pest larvae (Colorado potato beetle, wireworms, nematodes) that specifically attack potatoes accumulate in the soil (Welbaum, 2015). Each year their numbers increase, and even the strongest chemical treatments become ineffective.
• Depletion and nutrient imbalance: Potato is a crop with high requirements for nitrogen and especially potassium (De Jong et al., 2011). If planted year after year, it “draws” the same elements from the soil, reducing them to a critical minimum. Meanwhile, other macro- and micronutrients may accumulate, disrupting balance and reducing fertility.
• Deterioration of soil physical properties: The potato root system is relatively weak, but it leaves a compacted layer at a depth of 20–30 cm. Continuous cultivation without deep loosening and organic matter leads to structural deterioration, reduced air permeability, and water-holding capacity (Tarakanov and Mukhin, 2003).

3.2. The Golden Rule: Return No Earlier Than After 3–4 Years

This is the main rule you must remember: potatoes can be returned to the same place no earlier than after 3–4 years (Balashev and Zeman, 1981; De Jong et al., 2011). During this time, most pathogens and pest larvae remaining in the soil die off without a “host”—the potato plant. The soil also restores its structure and “rests” from the intensive consumption of potassium and nitrogen.

3.3. Good and Bad Predecessors: Whose Bed Is “Inherited”

Knowing what grew in the bed before potatoes allows you to predict soil condition and plan in advance whether it needs additional fertilizers or, conversely, sanitation.

Categorically bad predecessors:

These are all plants from the Solanaceae family. They are “relatives” of potatoes and suffer from the same diseases (late blight, verticillium wilt, viruses, scab) and pests (nematodes, Colorado potato beetle) (Navarre and Pavek, 2014).

• Potatoes (including early ones).
• Tomatoes.
• Eggplants.
• Peppers (sweet and hot).
• Tomatillos.

Why is this bad? Diseases and pests left from the previous crop attack the new potatoes from the first days of life, leaving them no chance for proper growth.

Neutral predecessors (acceptable, but not recommended):

These are crops that have no common diseases with potatoes but consume many nutrients (especially nitrogen). They will require additional nitrogen fertilizer before planting potatoes.

• Beets, carrots, radishes, turnips.
• Sunflower, corn.

Best predecessors (ideal):

These are crops that either sanitize the soil, enrich it with organic matter and nitrogen, or are not “competitors” for nutrients.

1. Legumes (peas, beans, broad beans, soybeans, lupine): Absolute leaders. Nodule bacteria on the roots of these plants fix atmospheric nitrogen and convert it into a form available to other plants. After legumes, a significant amount of readily available nitrogen remains in the soil, providing an excellent “launch pad” for potatoes (De Jong et al., 2011; Welbaum, 2015).

2. Brassicas (white cabbage, cauliflower, broccoli, oilseed radish, rapeseed): They have no common diseases with solanaceous plants, and their powerful root systems loosen the soil well. Moreover, many brassicas, especially mustard and rapeseed, are excellent green manures.

3. Cucurbits (cucumber, zucchini, pumpkin, squash): They are not affected by the main potato diseases, use organic fertilizers well, and leave the soil loose.

4. Onion, garlic: They possess phytoncidal properties that help suppress the development of some soil pathogens (Torikov and Sychev, 2018).

3.4. What to Do If the Plot Is Small?

Of course, on a classic “six-hundred-square-meter” plot, maintaining a 3–4-year crop rotation can be difficult. But there are several tricks to mitigate the negative consequences:

• Planting after green manures: This is the best option for small areas. Immediately after harvesting early potatoes or other crops, sow a fast-growing green manure on the freed bed: white mustard, phacelia, winter rye, or vetch. After 1–2 months, incorporate the green mass into the soil. This disinfects the soil, enriches it with organic matter and nitrogen, and by next spring the bed will be in ideal condition.
• Combined plantings: In some cases, you can plant potatoes mixed with legumes (e.g., bush beans) or other crops that do not suppress them. However, this method requires more careful study of compatibility.
• Replacing the topsoil: If the plot is very small, you can remove the top 10–15 cm of soil after harvesting potatoes and replace it with fresh compost or fertile soil.

Conclusion for Chapter 3:

Crop rotation is not a whim of agronomists but a fundamental law of healthy farming. If you want your potatoes to stay healthy and produce stable yields, remember:

• Do not plant potatoes after solanaceous crops (tomatoes, peppers, eggplants).
• Return potatoes to the same place after 3–4 years.
• Use the best predecessors—legumes, brassicas, cucurbits.
• Actively use green manures on small plots.

By following this simple rule, you will save money on chemicals and get tasty, healthy harvests that will delight you and your family.

4.1. Deep Digging (Plowing): “Soil Health Operation”

Autumn digging is the main mechanical impact on the soil. It serves several purposes.

To what depth should you dig?

• Ideal—to the depth of a spade blade (20–25 cm). This is the depth where the bulk of potato roots develop (Dean, 1994).
• For heavy clay soils—with turnover of the layer. This means the topsoil is turned over, bringing the lower layer to the surface. This helps “freeze out” pests and weeds and improves structure.
• For light sandy soils: Deep loosening without turnover is sufficient to avoid disrupting structure and promoting nutrient leaching (De Jong et al., 2011).

What to do with clods?

• On clay soils, clods are not broken up. Leave them large over winter. This allows the soil to freeze and loosen better, becoming more crumbly (Svaider, 1992).
• On sandy soils, clods are usually broken up to prevent wind erosion.

4.2. Adding Organic Matter: “Hearty Dinner” for Microorganisms

Potatoes are a crop that requires high organic matter content in the soil. Organic matter improves structure, nutrition, and water-holding capacity.

• What to apply: Well-rotted manure (2–3 years old), compost, humus.
• What not to apply in autumn under potatoes: Fresh manure! It contains many weed seeds, pathogenic bacteria, and, most importantly, too much undecomposed nitrogen. In spring it will start to “burn” and can damage young tubers and sprouts. Moreover, fresh manure promotes scab infection of tubers (De Jong et al., 2011). It is better to apply it in autumn under the preceding crop.
• Application rates: On average, it is recommended to apply 1.5–2 buckets of humus or compost per 1 sq. meter (or up to 40–50 kg per 10 sq. m) (Tarakanov and Mukhin, 2003).

4.3. Applying Phosphorus-Potassium Fertilizers: “Capital Repair” of Nutrition

Phosphorus and potassium are elements very important for potatoes. Phosphorus stimulates flowering and tuber formation, while potassium improves taste, storage quality, and disease resistance (De Jong et al., 2011).

Why apply them in autumn?

• Phosphorus is immobile in soil. It dissolves and becomes available to plants very slowly. Applied in autumn, it has time to distribute evenly in the soil by spring (Dean, 1994).
• Potassium is also better applied in autumn, especially on light soils, so that it does not leach out with meltwater but becomes fixed in the soil adsorption complex.

Which fertilizers to use?

• Superphosphate (single or double): An excellent source of phosphorus.
• Potassium sulfate: Preferable to potassium chloride, as chlorine can impair the taste and starch content of potatoes (Navarre and Pavek, 2014).

Approximate rates: For gardeners, it is difficult to give exact dosages without soil analysis, but on average you can aim for 30–40 g of superphosphate and 20–30 g of potassium sulfate per 1 sq. meter.

Important note: Nitrogen fertilizers (urea, ammonium nitrate) are not applied in autumn! They are very mobile and will leach deep into the soil with meltwater, becoming unavailable to plants in spring. Nitrogen is applied only in spring (Hochmuth and Siedeman, 2023).

4.4. Liming: “Treatment” of Acidic Soils

If soil analysis shows your plot is too acidic (pH below 5.0–5.5), autumn is the best time for liming.

• What to apply: Dolomite flour, ground limestone, chalk.
• Why: Liming reduces acidity, enriches soil with calcium and magnesium. However, this should be done not immediately before potatoes, but one to two years before planting, under preceding crops, as lime can promote scab development (Welbaum, 2015).
• Rates: Depend on initial acidity and soil type. On average, to reduce acidity by 1 pH unit on loams, about 300–400 g of dolomite flour per 1 sq. meter may be needed.

4.5. Sowing Green Manures: “Green Fertilizer” for Soil Health

This is one of the most effective and environmentally friendly methods of autumn preparation. If your potatoes were harvested early (in July–August), you can sow fast-growing green manures on the freed area.

• What to sow: White mustard, phacelia, winter rye, vetch, rapeseed.
• Why: Green manures enrich the soil with organic matter and nitrogen, prevent nutrient leaching, suppress weed growth, and improve soil health (De Jong et al., 2011; Torikov and Sychev, 2018).
• How to use: The green mass is cut or incorporated into the soil in late autumn, 2–3 weeks before the onset of cold weather.

Conclusion for Chapter 4:

Autumn preparation is your main tool for building healthy and fertile soil. Do not spare time and effort on:

1. Deep digging: improves structure and combats pests.

2. Adding organic matter (humus, compost) and phosphorus-potassium fertilizers: these are “slow-release” nutrients.

3. Liming: if necessary, do it in autumn.

4. Sowing green manures: do not leave the soil bare after harvest.

In spring, you will only need to “open” moisture and do light loosening.

5.1. Closing Moisture: “Preserving” Winter Reserves

This is perhaps the most important and often underestimated spring technique. Soil that has been dug in autumn must be “closed” in spring—early spring harrowing or loosening as soon as it is physically ripe (i.e., stops smearing and starts crumbling) (Dean, 1994).

Why is this important?

• Moisture conservation: Over winter, soil accumulates moisture. In spring, with warmth and wind, this moisture begins to evaporate intensely from the surface. Harrowing or loosening breaks the capillaries through which water rises to the surface and creates a dry mulching layer that prevents evaporation from lower horizons (Pavek, 2014).
• Accelerated warming: The loose top layer warms up faster in the sun, promoting earlier and more uniform emergence (De Jong et al., 2011).
• Weed control: Early loosening destroys annual weed seedlings at the “white thread” stage when they are most vulnerable.

How to do it?

• For small areas: Raking or light cultivation with a flat cutter.
• Depth: Shallow, only 3–5 cm, to avoid turning over the top layer and mixing wet soil with dry.

5.2. Loosening and Leveling: “Preparing the Bed”

After closing moisture, immediately before planting, the soil must be finally prepared. Here an important rule applies: do not overdo it.

Why is this important?

• Looseness for tubers: Potatoes are very sensitive to compaction (De Jong et al., 2011). In dense soil, tubers find it difficult to fill out, become deformed, and oxygen availability decreases. Therefore, the soil should be loose and finely crumbly, but not pulverized into dust.
• Leveling: A flat surface ensures uniform planting depth, which is crucial for even emergence. It also simplifies subsequent care and watering.
• “Dust” is the enemy: Too fine, dusty soil structure after digging is bad. It compacts quickly, forms a crust that impedes sprout emergence, and dries out rapidly (Tarakanov and Mukhin, 2003).

How to do it?

• Depth: Spring digging should be shallow—about 15–18 cm (half a spade blade). This is enough to mix fertilizers with the soil but not turn up deep layers that have not yet warmed up (Hochmuth and Siedeman, 2023).
• Tools: On large plots—cultivation with a rotary tiller or cultivator. On small plots—digging with simultaneous loosening and leveling with a rake.

5.3. Pre-Planting Fertilization: “Starter Breakfast”

Potato tubers contain some nutrient reserves needed for the first shoots. But for a quick start and the formation of a strong bush, they need “supplementation.”

What to apply in spring?

• Nitrogen: This is the main element for building foliage. If you did not apply manure or humus in autumn, be sure to add nitrogen fertilizers in spring. It is important to apply them immediately before or during planting to avoid leaching (Dean, 1994).
• Phosphorus and potassium: If they were not applied in autumn, they can be added in spring, but phosphorus should be placed in rows or holes because it is immobile and must be accessible to roots immediately (De Jong et al., 2011).

Which fertilizers to use?

• For those who prefer mineral fertilizers: You can use complex fertilizers with an NPK ratio, e.g., nitroammophoska (16:16:16) or special “potato” blends. It is better to apply them in rows during planting, strictly following dosages to avoid burning roots.
• For organic farming supporters: Well-rotted compost (not fresh manure!), ash (source of potassium and micronutrients), and bone meal (source of phosphorus) (Torikov and Sychev, 2018).
• Important rule: All fertilizers should be separated from the seed tuber by a layer of soil (2–3 cm) to avoid chemical burns.

5.4. When to Start Spring Preparation?

The most common question: “When can I start?” There is a reliable folk sign and a scientific basis.

• Physical ripeness of soil: It occurs when the soil stops smearing and crumbles into lumps (Svaider, 1992). This usually happens one to two weeks later than field work begins.
• Soil temperature: For planting potatoes, the optimal soil temperature at the planting depth (8–10 cm) is about 7–8 °C (Balashev and Zeman, 1981; Pavek, 2014). If planted in cold soil, tubers may rot, and emergence will be uneven and late. If planted in too warm soil (above 25 °C), tuber formation may be suppressed (Welbaum, 2015).
• Spring tillage should be done as early as possible to prevent moisture loss, but not before the soil is mature. Therefore, harrowing (closing moisture) is often done first, and then after 5–10 days, digging or cultivation.

Conclusion for Chapter 5:

Spring preparation is a “sprint” where every detail matters. The main tasks:

1. Close moisture: prevent evaporation, keep moisture in the soil.

2. Loosen and level: create a comfortable environment for tubers, but do not pulverize the soil into dust.

3. Apply starter fertilizer: provide nutrition for rapid foliage growth, keeping in mind tuber safety.

4. Do not rush: wait until the soil warms to optimal temperature, but do not delay planting.

Proper spring preparation is the key to fast and uniform emergence, strong foliage, and a rich tuber set.

6.1. Fresh Manure: A “Hot” Mistake

This is perhaps the most popular and dangerous mistake. The desire to fertilize “for real” leads to incorporating fresh, unrotted manure into the bed.

Why is it bad?

• Root burn: Fresh manure contains large amounts of active nitrogen and organic acids. During decomposition, it releases heat and can literally “burn” delicate roots and young tubers. Plants will lag in growth, and tubers may rot (De Jong et al., 2011).
• Scab: Fresh manure is an excellent medium for the development of scab pathogen (Streptomyces scabies). Applying it immediately before planting almost guarantees tuber infection (Welbaum, 2015).
• Weeds: Fresh manure contains many weed seeds that will germinate vigorously in spring, smothering the plantings.
• Diseases: Fresh manure may contain pathogens and helminth eggs.

What is the right way?

Use only well-rotted manure (humus) or compost that has aged for at least 1–2 years. Fresh manure can only be applied in autumn, a year or two before planting potatoes, under preceding crops (Tarakanov and Mukhin, 2003).

6.2. Digging Heavy Clay in Muddy Conditions: The “Concrete” Effect

One of the most common mistakes on heavy clay soils is trying to dig them in early spring while they are still too wet.

Why is it bad?

• Structural damage: When working wet clay, its structure is destroyed. Instead of crumbly, loose soil, you get a structureless, sticky mass. When dried, it turns into “concrete” with huge clods (Svaider, 1992).
• Oxygen starvation: Such soil has practically no pores; it does not allow air to pass through. Roots suffocate, tubers cannot grow and become deformed (De Jong et al., 2011).
• Slow warming: Dense, wet clay takes a long time to warm up, delaying planting and emergence.

What is the right way?

Wait for physical ripeness of the soil. A good test: squeeze a handful of soil in your fist—if it does not form a tight ball and crumbles when dropped from a height of 1 meter, it can be worked. On heavy soils, it is especially important to perform deep autumn digging with layer turnover (De Jong et al., 2011).

6.3. Excess Nitrogen: “Fat” Foliage and “Empty” Tubers

Very often, gardeners trying to feed potatoes overdo nitrogen fertilizers.

Why is it bad?

• To the detriment of tubers: Nitrogen stimulates foliage (leaves and stems) growth at the expense of tuber formation. The plant “fats”: it develops lush, dark green leaves but sets few tubers (Navarre and Pavek, 2014; Balashev and Zeman, 1981).
• Delayed maturation: Excess nitrogen prolongs the growing season. Potatoes ripen late, which is especially critical in regions with short summers.
• Reduced quality: Nitrates accumulate in tubers, and starch content decreases. They store worse (De Jong et al., 2011).
• Diseases: Excess nitrogen weakens plant immunity, making them more vulnerable to fungal diseases and pests.

What is the right way?

Maintain balance. If you applied manure or humus, spring nitrogen fertilizers can be omitted entirely or applied at half the rate. Apply nitrogen fertilizers not all at once but in two or three split applications before budding begins (Dean, 1994).

6.4. Planting in Cold Soil: A “Frozen” Start

The desire to plant early to get an early harvest is understandable. But rushing to plant in unheated soil is a risky strategy.

Why is it bad?

• Delayed emergence: In cold soil (below 7 °C), tubers do not sprout. They lie in the ground waiting for warmth. Emergence occurs much later and unevenly (Pavek, 2014; Hochmuth and Siedeman, 2023).
• Rotting: In cold and wet soil, seed tubers are easily infected by fungal and bacterial rots (rhizoctonia, wet rot). Some tubers may simply rot without ever sprouting (Welbaum, 2015).

What is the right way?

Plant potatoes when the soil at the planting depth (about 10 cm) has warmed to 7–8 °C. In the middle belt, this usually occurs in late April – early May. Rely on folk signs: when bird cherry blossoms, you can plant, but it is better to check with a thermometer.

6.5. Over-Pulverizing Soil into “Dust”: A “Desert” Instead of a Bed

During spring preparation, some gardeners overdo loosening, turning the soil into fine dust.

Why is it bad?

• Crust formation: After the first rain or watering, dusty soil compacts, forming a hard crust. It prevents emergence and impairs gas exchange (Tarakanov and Mukhin, 2003).
• Erosion: Dusty soil is easily blown away by wind and washed away by water.
• Loss of structure: Valuable crumbly structure is destroyed in fine, uniform dust.

What is the right way?

Loosen the soil to a fine crumbly state with lumps of 1–3 cm. Do not dig it too often and do not use tools that “cut” the soil rather than loosen it.

6.6. Ignoring Predecessors and Crop Rotation

We already discussed this in detail in Chapter 3, but this mistake is so common that it is worth repeating here.

Why is it bad?

It leads to accumulation of diseases, pests, and soil depletion (Welbaum, 2015). Year after year, you will notice that potatoes become smaller, get sick more often, and pests become more numerous despite treatments.

What is the right way?

Do not plant potatoes after solanaceous crops (tomatoes, peppers, eggplants) and return them to the same place no earlier than after 3–4 years. Use the best predecessors: legumes, brassicas, green manures.

Main conclusion on all mistakes:

Soil preparation for potatoes is not a set of mechanical actions but a holistic system. All elements of this system are interconnected: soil structure, nutrition, pH, crop rotation. A mistake in one link can nullify all your efforts. Be attentive, do not rush, and always remember: healthy soil is the foundation of a healthy harvest.