Watering

Why is potato so dependent on water?

The reason lies in the root system structure. Contrary to popular belief, potato has a shallow and poorly developed root system. About 85% of the roots are located in the top 30‑cm layer of soil, and most water is absorbed from the 0–45 cm horizon (Ierna, 2023; Dean, 1994). Unlike many cereals, potato roots cannot extract water from deep soil layers during dry spells.

This makes potato extremely vulnerable even to short dry periods. When soil moisture drops, leaf turgor decreases, stomata close, and photosynthesis slows down. This directly affects yield (Levy & Coleman, 2014).

Potato consumes enormous amounts of water. On average, seasonal water consumption ranges from 350 to 625 mm (Ierna, 2023), and in hot regions it can reach 650–700 mm. This means that for every kilogram of dry matter, the plant uses 500 to 1000 litres of water.

Practical conclusion: on plots that receive less than 350–450 mm of rainfall per season, potatoes must be irrigated. If rainfall is higher but uneven, watering is still necessary to smooth out dry periods. If rains are sufficient and regular, watering may not be required.

When can one really do without watering?

In regions with cool and wet summers (e.g., parts of the Non‑Black Earth region of North‑West Russia, the Baltic states), potatoes may occasionally manage without irrigation without major yield losses. However, even there, irregular rainfall during critical growth periods can reduce yields by 30–50% (Andrianov & Andrianov, 2007). Therefore, even in risky farming zones, irrigation remains a crucial tool for increasing yield and stability.

Simple signs that potatoes lack water:

• leaves lose firmness and droop in the middle of the day;
• soil at 10–15 cm depth is dry and crumbly;
• stems slow their growth.

What does proper irrigation give?

Research shows that increasing irrigation from 0% to 100% of plant needs boosts fertiliser use efficiency by 77–128% (Ierna et al., 2011). This means that without water, even applied fertilisers do not work at full strength. With proper irrigation, potato yields increase 2–3 times compared to rainfed cultivation.

Thus, the answer to the question “Should potatoes be watered?” is unequivocally “yes”, especially in regions with dry summers. This is not a whim but a biological necessity. Remember the main rule: potatoes “grow by themselves” only where rains fall regularly and in sufficient amounts. In all other cases, watering is indispensable.

Phase 1. Planting – Emergence: Watering is More Harmful than Beneficial

Immediately after planting, tubers do not need abundant moisture. Moreover, watering into cold soil is dangerous: moisture displaces air from soil pores, and tubers may rot, especially at low temperatures. Studies show that excess moisture during this period increases the risk of Rhizoctonia infection and delays emergence (De Jong et al., 2011; Kotov & Adritskaya, 2016).

Practical rule: watering before emergence is justified only in one case – if the soil is so dry that tubers cannot start growing. Even then, the soil temperature should be at least +8…+10 °C. In most cases, the moisture left in the soil after winter or spring rains is sufficient for germination.

Phase 2. Emergence – Budding: Demand Increases

After emergence and before budding, the plant actively builds its leaf apparatus. However, water demand at this stage is not yet maximal: the seed tuber continues to supply the young plant with nutrients, and the root system is still forming.

Optimal regime: maintain soil moisture at 60–70% of field capacity. A slight moisture deficit during this period is even beneficial: it stimulates root development, encouraging roots to penetrate deeper (Dean, 1994). However, complete drying of the top layer is unacceptable – it slows leaf growth and delays subsequent phases.

Phase 3. Budding – Flowering: The Most Critical Period

This is the main “water window” in the potato’s life. It is during budding and flowering that the number of tubers is set and their active growth begins. At this stage, transpiration (evaporation through leaves) sharply increases, and any drought causes stress.

Research by Vos and Haverkort (2007) shows that even a short moisture deficit during budding reduces the number of tubers set, and this damage cannot be compensated later. With water shortage, the plant “sacrifices” future yield to preserve its own viability – some ovaries die off, and the remaining tubers become smaller.

Field experiments in the southern Urals (Andrianov & Andrianov, 2007) found that irrigation during this period increased early potato yields by 40–60% compared to non‑irrigated variants. The optimal soil moisture during budding–flowering is 75–85% of field capacity.

Important caution: if you are late with watering and the plants have already wilted, abundant watering can trigger cracking of tubers – more on this in Chapter 6.

Phase 4. Flowering – Beginning of Tops Senescence: Tuber Bulking

After flowering, the plant’s main task is to increase tuber mass. This period is also very important, although sensitivity to moisture deficit is somewhat lower than during budding. If water shortage occurs during active tuber bulking, then:

• tuber growth slows;
• starch content decreases;
• quality deteriorates – tubers become watery, and hollow hearts may appear.

Particularly dangerous are sharp moisture fluctuations: when a heavy watering follows a long drought. This causes uneven growth of tuber tissues and leads to cracks and misshapen forms (Ierna, 2023; Welbaum, 2015). Optimal moisture during this period is 70–80% of field capacity.

Phase 5. 2–3 Weeks Before Harvest: Stop Watering

Watering should be completely stopped 2–3 weeks before the planned harvest. This is an important rule often forgotten. Reasons:

1. The tuber skin must strengthen – this improves storage life and reduces damage during harvesting (Welbaum, 2015).

2. Excess moisture promotes diseases – wet rots, late blight, especially in warm weather.

3. Dry matter content decreases – tubers become watery and store poorly (De Jong et al., 2011).

Exception – extreme heat, when plants may die without water. In that case, a maintenance watering with minimal rates is permissible.

When Watering is NOT ALLOWED (even if it seems needed)

• In cold weather with soil temperatures below +10…+12 °C – roots hardly function, water stagnates and causes rotting.
• During rainy periods – excess moisture is as dangerous as deficit. Over‑wetting causes oxygen starvation of roots, lenticel growth (cracks on tubers), and development of rots (Navarre & Pavek, 2020).
• In hot midday – watering in the heat causes leaf burns and shock to the plant. The best time is early morning or evening after sunset.

Summary of Critical Periods

¹FC – field capacity. This is the amount of water that soil can hold against gravity. For simplicity, 100% FC is the state when soil is fully saturated but excess water has drained. 70% means soil is moist but not wet.

Remember the key: the critical time for watering is from budding to the end of flowering. If moisture is lacking precisely in this period, you risk losing most of the yield even with ideal watering at other times.

Danger No. 1. Cold and Wet Soil Immediately After Planting

This is perhaps the most insidious moment. Many novice gardeners, seeing dry soil after planting, immediately grab a watering can. This must not be done if the soil has not yet warmed to +10…+12 °C.

Why is it dangerous?

• Tubers in cold soil are in a state of physiological dormancy. Their respiration is slowed, and they do not actively consume water.
• Excess moisture displaces oxygen from soil pores, which is necessary for germination.
• In anaerobic (oxygen‑free) conditions, rot pathogens are activated: Pythium, Fusarium, bacterial soft rot.

Result: tubers do not germinate but rot. Emergence is delayed, sparse, and part of the seed material dies completely (De Jong et al., 2011; Kotov & Adritskaya, 2016).

Practical rule: the first watering after planting is permissible only if the soil has warmed to at least +10 °C at the planting depth (8–10 cm). If spring is cold and rainy, no watering is needed at all, even if the top layer seems dry. Moisture is present deeper – the tubers will find it.

Danger No. 2. Waterlogging and Over‑Wetting

Potatoes, contrary to popular belief, do not tolerate flooding. Even a short standing water for 24–48 hours can cause massive root death and disease development.

What happens with over‑wetting:

• Soil air is displaced by water, roots stop breathing.
• Nutrient uptake is disrupted, especially nitrogen and potassium.
• Lenticels (“breathing pores”) on tubers enlarge – they turn into white bumps that become entry points for infection (Vos & Haverkort, 2007; Navarre & Pavek, 2020).
• Fungal and bacterial diseases are activated: late blight, wet rot, Rhizoctonia.

Signs of over‑wetting:

• leaves turn yellow and droop even though the soil is wet;
• stems darken and soften at the base;
• a putrid smell comes from the soil;
• a green crust of algae and moss appears on the surface.

Practical conclusions:

• Do not plant potatoes in lowlands or areas with high groundwater – roots will constantly suffocate.
• If over‑wetting occurs, immediately stop watering and loosen the row spacings to provide air access to the roots.
• In a rainy summer, hilling helps divert water from stems and prevent rotting.

Danger No. 3. Late Watering Before Harvest

Watering in the last 2–3 weeks before harvest is one of the most common mistakes, especially in warm regions.

Why is it so critical?

1. Moisture delays tuber maturation and postpones natural top senescence.

2. Tuber skin does not have time to strengthen – it remains thin and is easily damaged during harvest.

3. Increased humidity during this period is ideal for late blight, which infects tubers directly in the soil.

4. Dry matter content decreases, thus starchiness decreases. Tubers become watery and store poorly (De Jong et al., 2011; Welbaum, 2015).

Practical rule: stop watering completely 2–3 weeks before harvest. Exception – only extreme heat when the plant may die. But even then, watering should be minimal and only between rows, without wetting the tops.

Danger No. 4. Watering in Hot Sunny Midday

It would seem that watering is especially needed in the heat. But if you water during the day when the sun is at its zenith, you can cause harm.

What happens:

• Water drops on leaves act like lenses, focusing sunlight and causing burns.
• A sharp temperature contrast – cold water on soil heated to +35…+40 °C – causes heat shock to the root system.
• Most of the water simply evaporates without reaching the roots – this is inefficient and wasteful.

Practical rule: water early morning (before 9–10 a.m.) or evening (after 6–7 p.m.). At these times, evaporation is minimal, water has time to soak in, and leaves dry before nightfall, reducing the risk of fungal diseases.

Danger No. 5. Surface Watering or Only Wetting the Top Layer

Sometimes gardeners water often but little by little – “to keep the soil always moist.” This is one of the most harmful approaches.

Why is it bad?

• Water does not reach the bulk of the roots, which lie at 20–30 cm depth. The roots remain in dry soil.
• The plant develops a shallow root system – even more vulnerable to drought.
• Constant wetting of the top layer creates ideal conditions for weed germination and disease development.
• Evaporation from the soil surface leads to crust formation, which impedes root respiration.

Golden rule: water infrequently but abundantly. The watering should wet the soil to at least 30–40 cm depth. This stimulates deep root development and makes plants more drought‑resistant.

When Watering Potatoes is Absolutely Forbidden – Quick Checklist

Remember the Main Point

Water is not always a boon for potatoes. Water only when it is needed (Chapter 2) and only at the right time. Do not water into cold soil, do not water before harvest, do not water at midday, do not water superficially. By following these simple rules, you will preserve both yield and plant health.

Sign No. 1. Loss of Turgor (Leaf Wilting)

Turgor is the elastic state of tissues maintained by water pressure inside cells. When moisture becomes scarce, cells lose pressure and leaves droop. This is the earliest and most obvious symptom.

What it looks like:

• On a hot sunny day, leaves droop, become limp, “cloth‑like”.
• Stems may lean slightly.
• If compared to morning – in the morning leaves are firm and stand horizontally, but by midday they droop – this is a clear sign that roots cannot supply water fast enough to meet transpiration.

But there is a nuance: slight wilting at midday in heat may be temporary – if leaves recover turgor by evening, there is no critical deficit (Dean, 1994; Levy & Coleman, 2014). This is a normal reaction to high temperature. But if by the next morning leaves remain droopy – that is an alarm signal.

Threshold values: research shows that when leaf water potential drops below –0.4…–0.5 MPa, tuber growth stops (Navarre & Pavek, 2020). In practice, this corresponds to a situation where the plant does not recover turgor even by morning.

Remember: if leaves are already wilted in the morning – watering is needed immediately. If only during the day – you can wait until evening, but prepare to water.

Sign No. 2. Changes in Leaf Colour and Texture

With prolonged moisture deficit, leaves change colour and texture:

• Dark green with a bluish tint – the plant tries to reduce evaporation by closing stomata and slightly changing the reflective properties of the surface. The leaf blade appears darker and duller.
• Yellowing and drying of lower leaves – the plant sacrifices old leaves, moving water and nutrients to young shoots and tubers. This is acceptable in moderate amounts, but if more than 20–30% of leaves turn yellow – the problem is serious.
• Leaf curling – under severe water deficit, leaf blades may roll into a tube, reducing evaporation area.

Important: do not confuse these signs with other problems. Yellowing of lower leaves can also be caused by nitrogen or potassium deficiency, and curling by viral diseases or herbicide stress. Therefore, assess the plant’s condition as a whole.

Sign No. 3. Soil Condition

Soil is the main indicator, but it must be assessed correctly. Do not judge only by the top layer – it always dries faster.

How to properly check soil moisture:

1. Manual method (“finger test”): scrape away the top layer and insert your finger to a depth of 8–10 cm. If at that depth the soil is dry and crumbly, does not form a clod – it is time to water. If moist and cool – watering is not yet needed.

2. Method with a spade or auger: dig a small hole to the depth of a spade blade (about 20–25 cm). Assess moisture at different horizons. If at 15–20 cm depth the soil is dry – the root system is in a deficit zone, watering is urgently needed (Vos & Haverkort, 2007).

3. Cracks in the soil. When the soil dries to the point of forming cracks more than 2–3 cm deep – that is already an advanced stage of drought. By that time, root and tuber growth has practically stopped. This should not be allowed.

Approximate guideline: watering should be carried out when soil moisture in the root zone (0–30 cm) drops to 65–70% of field capacity (Ierna, 2023). For most gardeners, this means: if at 10–15 cm depth the soil does not compress into a handful but crumbles – it is time to water.

Sign No. 4. Growth Stagnation

Water is the main driver of cell expansion. When moisture is insufficient, cells stop elongating, and above‑ground growth slows or stops completely.

How to notice:

• Apical shoots stop lengthening – no growth over 3–5 days.
• Fewer new leaves appear, and they are smaller.
• Lateral shoots (suckers) develop weakly or do not appear.
• Buds and flowers may drop without opening.

Why this happens: under water stress, the plant switches to an economy mode – stops shoot and leaf growth to conserve water for vital processes. This is especially critical during budding and flowering: if growth stops, tubers do not set in the required number (Dean, 1994).

Practical tip: every 2–3 days, measure the height of several plants marked with stakes. If there is practically no growth over a week – the problem is water (or nutrition, but more often water).

Sign No. 5. Indirect Signals

• Appearance of pests. In dry weather, aphids, spider mites, and leafhoppers become more active – they prefer weakened plants with low tissue moisture.
• Early flowering. Sometimes under stress, the plant tries to accelerate its reproductive phase to leave offspring – and blooms earlier than normal. This is an unfavourable sign indicating that the plant wants to “escape” from poor conditions.
• Changes in weed behaviour. If weeds around potatoes are wilting or yellowing – then the cultivated plants also lack moisture.

How Often to Check?

In hot dry periods – daily at midday. In cool weather or cloudy conditions – 2–3 times a week is enough. After watering, check the next day to assess the wetting depth.

What to Do If Signs Have Already Appeared?

If you notice wilting or growth stagnation – do not wait for rain, start watering. But do not flood abruptly! Apply water gradually so that the soil can absorb it without puddles. In case of severe wilting in heat, it is advisable to first do a light refreshing watering (5–10 L/m²), and after 1–2 hours the main watering, to avoid shock from a sharp change in moisture.

Quick Checklist for Daily Monitoring

Remember the main point: it is better not to let plants reach wilting. That is already stress that reduces yield. Water when you notice the first signs of drying soil in the root zone.

5.1. Wetting Depth: Why 30–40 Centimetres

As already mentioned, the bulk of potato roots is in the 0–30 cm layer, and the maximum root activity is at 15–25 cm (Dean, 1994; Ierna, 2023). Therefore, watering should wet the soil to at least 30 cm, preferably 40 cm. Only such depth ensures that moisture reaches the main root mass, rather than remaining in the top layer where it quickly evaporates.

Why depth is so important:

• Shallow watering (5–10 cm) encourages roots to grow upward, towards the surface, making plants more vulnerable to drought.
• Deep watering, on the contrary, stimulates root development deeper, increasing plant resistance to temporary moisture deficits.
• Moisture that reaches 30–40 cm depth evaporates more slowly and stays in the soil longer, especially in hot weather.

How to check wetting depth:

The most reliable method is to dig a small hole 2–4 hours after watering and measure how deeply water has penetrated. For convenience, use a spade: if the soil is moist to about 25–30 cm depth, the watering is sufficient.

Practical recommendation: on sandy loam and loam soils, the irrigation rate should ensure wetting to 30–40 cm. On average, this requires about 25–30 litres of water per 1 m², or 250–300 m³/ha (Welbaum, 2015; Vos & Haverkort, 2007).

5.2. Watering Frequency: How Many Times and When

Watering frequency depends on several factors: plant growth stage, weather conditions, soil type and its water‑holding capacity. General guidelines are as follows (De Jong et al., 2011; Ierna, 2023):

• Sandy and light soils hold moisture poorly; they need more frequent watering but with smaller rates.
• Loam and clay soils retain moisture longer, so they can be watered less frequently but with increased rates to wet the entire root zone.

By growth phases:

Important: do not water “on a schedule”, but rather based on soil condition. In hot dry weather, frequency may increase to 2–3 times per week, especially on light soils. In cool and rainy weather, intervals can extend to 10–14 days. The main criterion is soil moisture at 20–25 cm depth.

5.3. Watering Rate: How Much Water to Apply

Watering rate is the amount of water per unit area per application. It should be sufficient to wet the soil to the required depth, but not excessive to cause waterlogging and leaching of nutrients.

Approximate rates for different soils and conditions:

• Light sandy and sandy loam soils: 20–25 L/m² (200–250 m³/ha) per watering. Water more often (2–3 times per week in heat), but with smaller rates.
• Medium loams: 25–30 L/m² (250–300 m³/ha). Water less often but more abundantly.
• Heavy clay soils: 30–35 L/m² (300–350 m³/ha). Water even less often but with a larger rate to allow water to penetrate deep.

Checking adequacy: after watering, dig a hole to 30 cm depth. If the soil is moist throughout – the rate is correct. If at 15–20 cm it is dry – increase the rate and/or frequency.

Important caution: irrigation rates in hot weather on light soils may be higher because evaporation is greater. In such conditions, the rate may reach 35–40 L/m², but only provided that water soaks in and does not run off the surface.

5.4. Irrigation Methods: Pros and Cons

1. Furrow irrigation (if planted in ridges or raised beds)

This method is often used on flat fields with row spacings.

• Pros: simplicity, no special equipment needed, water goes directly to the rows.
• Cons: uneven distribution, significant water losses to evaporation and deep percolation, risk of erosion on slopes, labour‑intensive.

With this method, water is let into furrows between ridges and seeps sideways to the roots. It is important that water does not rise above the middle of the ridge – otherwise tubers may become waterlogged and rot.

2. Sprinkler irrigation (overhead watering)

Mimics natural rain.

• Pros: uniform wetting of the entire area, cooling plants in heat.
• Cons: increases the risk of fungal diseases (especially late blight) due to prolonged leaf wetting; requires more frequent watering due to evaporation losses; may compact soil under droplet impact.

Sprinkler rules: water best in the morning so that leaves dry before evening. In heat, sprinkling should be done only in the morning or evening. During flowering and tuber bulking, avoid sprinkling to not provoke late blight.

3. Drip irrigation (most efficient)

Water is delivered drop by drop directly to the roots via tape or tubing.

• Pros: minimal water losses, precise dosing, can be combined with fertigation, leaves stay dry – diseases develop less, water savings up to 40–60% (Ierna, 2023; De Jong et al., 2011).
• Cons: high equipment cost, risk of emitter clogging, installation complexity on large areas.

Drip irrigation is the best choice for gardeners who care about yield quality and water saving. It is especially effective on light soils where other methods lead to water losses.

Drip irrigation is the choice of professionals. If you have the opportunity to install a system – definitely use it. It will pay off through yield increases and water savings.

5.5. Basic Rules of Proper Watering

1. Water at the root, not on the leaves. If using a hose or watering can, pour water on the soil around the bush, without wetting the foliage. This reduces disease risk and increases water use efficiency.

2. Water in the morning or evening. In hot midday, most water evaporates without reaching roots. Optimal time – early morning (before 9:00) or evening (after 18:00).

3. Water should be warm. Cold water (especially from a well) causes root stress. If possible, let water warm up in a container before watering.

4. Water infrequently but abundantly. Do not replace full watering with light sprinklings – that leads to shallow roots and weakened plants.

5. Use mulching. A layer of mulch (straw, mown grass, black film) reduces surface evaporation and cuts watering frequency by 20–30%.

6. In extreme heat – backup. If air temperature exceeds +30 °C during active growth, a light refreshing watering at the hottest time (10–15 L/m²) can help the plant survive stress, but does not replace main watering.

Summary of Watering Technique

Remember the main rule of watering potatoes: it is better to water heavily once than lightly three times. Deep and infrequent wetting encourages a strong root system, which makes plants resilient and productive.

Mistake No. 1. Surface Watering – “Often but Little by Little”

This is the most common mistake, especially among novice gardeners. Wanting to “support” the plants, they water potatoes every day with 5–10 litres per square metre. The water wets only the top layer (5–8 cm) and never reaches the roots.

Why it is harmful:

• Roots remain in the surface layer and do not develop deeper. The plant becomes extremely vulnerable even to short droughts – because the top layer dries out fastest (Dean, 1994; Vos & Haverkort, 2007).
• Constant wetting of the top layer creates ideal conditions for weed germination.
• A crust forms on the soil surface, hindering root respiration and evaporation of excess moisture.
• Nutrients from fertilisers remain in the top layer, not reaching the main root zone.

How to avoid: water infrequently but abundantly. One good watering per week (25–30 L/m²) is more effective than daily spraying. Water should wet the soil to at least 30 cm depth. Check this by digging a hole a few hours after watering.

Mistake No. 2. Sharp Moisture Fluctuations – The Cause of Tuber Cracking

Imagine: there was a long dry period, the soil dried out, plants began to wilt. And then – a heavy watering or heavy rain. What happens to the tubers?

Damage mechanism:

During drought, tuber growth slows and tissues become denser. When water suddenly arrives, cells start growing and dividing rapidly, but the outer skin (periderm) has already lost elasticity. Internal pressure ruptures it – cracks appear, which may be superficial (netting) or deep, reaching the middle of the tuber (De Jong et al., 2011; Welbaum, 2015).

Consequences:

• Cracks are entry points for infections, especially late blight and wet rots.
• Yield loses marketable appearance; such tubers store poorly.
• Starch content decreases – tubers become watery.

How to avoid: do not allow severe soil drying. If plants have already started wilting – before abundant watering, first do a light refreshing watering (10–15 L/m²) to prepare the soil. After 1–2 hours, carry out the main watering. Gradual moistening reduces the risk of cracking.

Mistake No. 3. Watering with Cold Water in Heat

It would seem that in hot weather you want to give plants cool water. However, cold water (especially from a well or borehole, with temperature below +12…+15 °C) causes severe stress to potatoes.

What happens:

• Sharp cooling of the root zone causes shock; roots stop absorbing water.
• Temperature contrast (hot soil – cold water) can damage root hairs.
• On leaves with sprinkling, cold water causes burns – drops act as lenses, and the cold shock intensifies damage (Kotov & Adritskaya, 2016).

How to avoid: use water that has had time to warm up in a container (barrel, tank) to at least +18…+20 °C. If watering from a hose, do it in the evening when water in the pipes has already warmed during the day. With drip irrigation the problem is less acute because water goes directly to the roots, bypassing leaves.

Mistake No. 4. Watering at the Wrong Time of Day

Watering in hot sunny midday is another common mistake. It is dangerous for several reasons.

Why daytime watering is dangerous:

• Most of the water (up to 40–50%) evaporates without reaching roots.
• Drops on leaves focus sunlight, causing burns.
• Sharp temperature contrast (cold water on warm soil) causes stress.
• With sprinkling, prolonged leaf wetting in heat creates ideal conditions for late blight and other fungal diseases (Navarre & Pavek, 2020).

How to avoid: water potatoes in the morning (before 9:00) or evening (after 18:00). Morning watering is preferable: leaves have time to dry before heat sets in, and moisture is well absorbed into the soil. Evening watering is also acceptable, but it increases disease risk because leaves remain wet all night.

Mistake No. 5. Watering After Rain “Just in Case”

Sometimes gardeners water potatoes “just in case” even after a light rain. This can lead to over‑wetting.

Why it is dangerous:

• Excess moisture displaces air from the soil, roots begin to suffocate.
• In wet soil, rots and fungal diseases develop quickly.
• Excess moisture during tuber bulking reduces dry matter content and impairs flavour.

How to avoid: check soil moisture at 15–20 cm depth before watering. If it is moist there – watering is not needed, even if the top layer is dry. Use the simple “finger test” or dig a hole. Water only when the soil in the root zone is indeed dry.

Mistake No. 6. Watering After Hilling and Cultivation – Without Considering Soil Condition

Hilling and loosening improve aeration, but if you give abundant watering immediately after, you can nullify the benefit.

Why:

• After loosening, the soil is more friable and easily compacted under water impact.
• Watering may wash away fresh ridges and expose tubers, causing them to green.
• Water can stagnate in loose soil, creating muddy “baths” around stems.

How to avoid: when hilling or loosening, water lightly before the operation to make the soil moist and not dusty, but do not flood. Main watering should be done 2–3 days after hilling, when ridges have naturally settled.

Mistake No. 7. Stopping Watering Too Early

The opposite situation also occurs: gardeners, knowing that watering before harvest is harmful, stop it too early – a month or more in advance. In dry hot weather, this leads to tuber growth cessation and yield reduction.

How to avoid: stop watering 2–3 weeks before harvest, not earlier. In hot weather, you can do one maintenance watering 10–14 days before gathering. The main thing is not to let the soil dry out completely during active tuber bulking.

Mistake No. 8. Sprinkler Irrigation During Flowering and Tuber Bulking

Sprinkling is a convenient method, but during the period from budding to the onset of top senescence it is especially dangerous.

Why:

• Prolonged wetting of leaves and stems during this period is the main cause of late blight outbreaks.
• Water that gets on flowers can disrupt pollination and reduce tuber set.
• With sprinkling, part of the water runs off leaves and does not reach the root zone.

How to avoid: during flowering and tuber bulking, use root‑zone watering – by furrows or drip. If sprinkling is unavoidable, do it early in the morning so that leaves dry completely before evening.

Checklist: How to Avoid Watering Mistakes

Conclusion

Proper watering of potatoes is not just “pouring water”. It is a comprehensive system that requires attention to timing, rates, methods, and plant condition. By avoiding the above mistakes and following the recommendations from previous chapters, you will be able to:

• increase yields by 1.5–2 times compared to unsystematic watering;
• obtain tubers with high starch content and excellent taste;
• reduce the risk of diseases, especially late blight and rots;
• ensure good storability of tubers.

Remember three main rules:

1. Water infrequently but abundantly – water must reach the roots.

2. Avoid sharp moisture fluctuations – this is the main cause of tuber cracking.

3. Water at the right time – morning or evening, with warm water, and only as needed.

Following these rules, you will get a healthy and high‑quality potato crop even in a dry summer.