When to plant cucumbers – calendar, tips and benefits

12 min 30/05/2025

Cucumbers are one of the most popular crops in Ukrainian gardens. They grow quickly, bear fruit abundantly and are well suited for fresh consumption or preservation.

But in order to grow strong plants and get a truly generous harvest, it is important to choose the right time for planting. In spring, the weather often changes, and it is precisely the accuracy in choosing the time that becomes decisive.

Optimal conditions for planting cucumbers

Cucumbers are a heat-loving crop that requires stable heat for germination and active growth. For successful sowing, the soil at a depth of about 10 centimetres must warm up to at least +14…+16°C. The daytime air temperature should not fall below +18°C, and at night it should not drop below +10…+12°C.

If the seeds are sown earlier, they may not germinate or may rot, and the seedlings may die from return frosts. On the other hand, planting too late reduces the length of the growing season, and part of the crop may not have time to ripen before the autumn cold snap.

Cucumbers thrive in well-lit, wind-protected areas with evenly moist soil. Excess water is just as harmful to them as a lack of water. Sudden temperature fluctuations, prolonged rains or nighttime cold spells can cause stress in plants, slowing growth and increasing the risk of disease. That is why the decisive criterion for planting should not be the calendar date, but stable spring weather.

When to plant cucumbers in different regions of Ukraine

The timing of planting cucumbers in Ukraine varies significantly depending on the region. The main reason for this is the different lengths of the spring period, the speed at which the soil warms up, and the stabilisation of night-time temperatures.

In the southern regions, spring comes earlier, so cucumbers can be sown as early as the end of April. In the central regions, planting is usually carried out in the middle or second half of May, and in the north and west of the country, it is worth waiting until the end of May or even the beginning of June.

In greenhouses or under temporary shelters, the timing can be moved up by 2-3 weeks, as the plants are protected from the night cold. But even in closed ground, it is worth focusing on temperature stability: cucumbers cannot withstand hypothermia.

Below is a summary table of recommended planting dates in open ground:

Region of Ukraine	Approximate Sowing Period	Planting Features
Southern regions	Late April – early May	Soil warms up early, direct sowing is possible
Central regions	Mid to late May	Optimal time for seedlings or seeds
Northern and Western regions	Late May – early June	Risk of night frosts persists longer

This regional differentiation allows you to avoid losses associated with weather risks and choose the best time for planting according to the climatic conditions of your area.

Sowing calendar for cucumbers according to moon phases

The phases of the moon affect the growth of many crops, and experienced gardeners often rely on this natural rhythm. For cucumbers, the most favourable period is considered to be the waxing moon phase, as this is when the growth processes of the above-ground part of the plant are activated. If seeds are sown during this period, seedlings usually appear faster and the plants themselves are stronger.

It is best to avoid sowing during the new moon or full moon, as this is an unstable period when seeds may not germinate well. The waning moon phase is also not considered ideal for cucumbers, as it slows down the development of shoots.

Using the lunar phases is not mandatory, but for many gardeners it is another guideline that helps not only to choose the right planting time, but also to avoid the risks associated with weather fluctuations. The main thing is not to put the calendar above common sense: the final decision should always be based on air temperature and soil condition.

How to properly prepare cucumber seeds for sowing

Seed preparation is one of the most important steps before sowing cucumbers. Even fresh seeds need to be treated to increase germination and reduce the risk of disease. Proper preparation will help you get friendly seedlings and strong plants.

Here are the main steps to take before sowing:

Sorting. Select healthy seeds without damage, dark spots or signs of mould. It is best not to use small or very light seeds.
Germination test. Soak the seeds in water for 10–15 minutes. Those that float are unsuitable for sowing. For a more accurate check, you can leave the seeds in water for 6–8 hours.
Disinfection. Dip the seeds in a weak solution of potassium permanganate (1 g per 100 ml of water) for 15–20 minutes, then rinse thoroughly with water. This reduces the risk of fungal diseases.
Soaking. Place the seeds in warm water (+25…+28°C) or a growth stimulant solution (e.g. Epin, Humat). Duration – 12-24 hours. The seeds should swell but not sprout.
Germination. Wrap the swollen seeds in a damp cloth or gauze and keep them in a warm place. After 1–2 days, sprouts will appear – after that, the seeds can be sown.
Hardening. To increase resistance to temperature changes, after soaking, the seeds are placed in the refrigerator (0…+2°C) for several hours, and then returned to a warm place. The procedure is repeated 2–3 times.

Also pay attention to the age of the seeds. Seeds that are 1–3 years old give the best results. Seeds that are too fresh produce many male flowers, while seeds that are too old germinate poorly or do not germinate at all.

Preparing the soil before planting cucumbers

Cucumbers require light, fertile and well-warmed soil. They grow best on loamy or sandy loam soils with a neutral or slightly acidic reaction (pH 6–7). The soil should be loose, moisture-retentive and well-drained — waterlogging is detrimental to this crop.

If organic fertilisers were not applied to the site in autumn, this should be done in spring, 7–10 days before sowing. 5–7 kg of humus or compost per 1 m² is sufficient. Additionally, wood ash (150–200 g) and superphosphate (20–30 g) can be applied. Fertilisers are evenly distributed over the surface and incorporated into the soil during digging to a depth of 20–25 cm.

Cucumbers are very sensitive to dense soil, so after digging, the soil should be well loosened to ensure air access to the roots. 1–2 days before sowing, the beds are slightly moistened, and immediately before sowing, the surface is levelled to avoid water stagnation in the depressions.

The choice of location is also important. Cucumbers love warmth and light, so the bed should be sunny, protected from the wind, but not in a low-lying area. The best predecessors are cabbage, onions and legumes. Do not plant cucumbers after pumpkin crops (zucchini, pumpkin, melon), as they have common diseases and pests.

Well-prepared soil is the key to rapid seed germination, strong root development and long-lasting fruiting throughout the season.

Technique for planting cucumbers in open ground

In order for cucumbers to take root well, sprout quickly and produce a stable yield, it is important to choose the right planting method and adhere to basic technical requirements.

The sowing method depends on weather conditions, soil type, timing and the gardener’s personal preferences. Each case has its own characteristics that should be considered in advance.

Direct sowing

Direct sowing is the simplest and most common method of growing cucumbers, especially in southern and central regions, where spring comes early and warms the soil quickly. In favourable weather conditions, cucumbers can be sown in open ground as early as late April or early May.

Before sowing, beds 20–30 cm high are formed so that the soil warms up better and moisture does not stagnate. The distance between rows is 70–90 cm, and between holes – 30–40 cm. Two to three seeds are placed in each hole at a depth of about 2–3 cm. After sowing, the soil is lightly compacted and watered with warm water.

If the weather is unstable, the beds are covered with plastic film or agrofibre. This helps to retain heat and moisture and also protects the seedlings from possible night-time cold spells. After the sprouts appear, the cover is removed or partially opened to harden the plants.

In warm spring conditions, direct sowing ensures friendly sprouting and yields a harvest almost simultaneously with the seedling method, without unnecessary labour costs.

Seedlings

Growing cucumbers from seedlings is a method that allows you to get an early harvest, especially in regions with cool springs or short growing seasons. This approach is also convenient for those who want to select the strongest plants in advance and plant them in open ground when they are already strong.

Seedlings should be prepared approximately 20–25 days before planting in open ground. It is most convenient to use individual containers – peat pots or plastic cups with a volume of 300–500 ml. They allow you to avoid pricking out and damaging the roots during transplanting.

The soil mixture for seedlings should be light, nutritious and well-aerated. The optimal ratio is 2:2:1 of turf, humus and sand. The seeds are buried 1.5–2 cm deep, watered and placed in a warm place with a temperature of +22…+25°C.

For successful development, seedlings need good lighting (at least 12 hours a day), regular watering with warm water and protection from drafts. When 3–4 true leaves appear on the plants and the weather stabilises, the seedlings are transplanted into the ground using the transshipment method.

The seedling method is especially effective in cases where there is a risk of return frosts or when it is necessary to harvest as early as possible.

How to care for cucumbers after planting

After planting cucumbers, the main task is to create conditions in which the plants will quickly take root, grow actively and produce strong leaves and flowers. At this stage, it is important to ensure stable humidity, warmth and nutrition.

Cucumbers require regular but moderate watering. The water should be warm (+20…+25°C) so as not to cause stress to the root system. Water at the root, trying not to wet the leaves. In the first week after planting, water daily or every other day, then as needed, depending on the weather.

After each watering or rain, it is advisable to loosen the soil around the plants – this improves oxygen access to the roots and reduces the risk of crust formation. It is also worth mulching the soil – with straw, rotted humus or agrofibre – this reduces moisture evaporation and inhibits weed growth.

10–14 days after planting, the cucumbers are fertilised for the first time. At the stage of vine formation, nitrogen fertilisers are used, and during flowering and fruiting, phosphorus-potassium or complex fertilisers are used. Fertilisation is carried out at the root, preferably after watering.

Also, monitor the condition of the leaves. If signs of chlorosis or fungal diseases appear, take appropriate measures – biological preparations, fungicides or folk methods, if the damage is minor.

In the first weeks of growth, it is especially important to prevent overheating or sudden cold snaps. In unstable weather, plants should be covered with film or agrofibre at night.

Common mistakes when planting cucumbers

The most common mistakes when planting cucumbers can significantly reduce the yield or completely negate all efforts. Here’s what to avoid:

Planting too early. If the soil is cold, the seeds will rot and the seedlings will not emerge or will die due to frost.
Dense sowing. Plants begin to compete with each other, ventilation deteriorates, the risk of disease increases and the quality of the fruit decreases.
Watering with cold water. This causes shock to the root system, delays growth and provokes fungal diseases.
Planting after pumpkin crops. Disease pathogens common to cucumber relatives may remain in the soil, increasing the risk of infection.
Irregular or excessive watering. Both drying out and waterlogging are equally harmful: the former stops growth, the latter causes root rot.
Neglecting seed preparation. Failure to soak or treat seeds against fungi often leads to uneven germination or damage to seedlings.
Poorly prepared soil. Dense, acidic or nutrient-poor soil prevents plants from developing normally.

Careful adherence to planting technology is the best way to avoid these mistakes and ensure a stable harvest.

Tips for getting an early harvest of cucumbers

To harvest the first cucumbers in June, it is important not only to choose the right time for sowing, but also to create conditions that stimulate rapid plant development. Here are some effective ways to help speed up the harvest:

Use the seedling method. This allows you to plant already strong plants in the ground and get fruits 2–3 weeks earlier.
Prepare warm beds. Adding organic matter to the soil, which decomposes with the release of heat, accelerates the germination and development of cucumbers.
Use coverings. Agrotextile or film creates a microclimate, protects against sudden cold snaps and helps to retain heat after planting.
Choose early-maturing varieties. Their growing season is shorter, which means that the fruits appear earlier. Pay attention to the description of the ripening period on the packaging.
Use natural stimulants. These can be algae extracts, humic substances or ash infusions – anything that supports the plant’s metabolism and improves its resistance.
Ensure uniform moisture and stable heat. These factors have the greatest impact on the growth rate of cucumbers in the first weeks.

The comprehensive application of these tips will significantly bring forward the moment of harvesting the first crop without compromising the quality of the fruit.

Conclusion

To grow healthy, juicy and productive cucumbers, it is not enough to simply throw seeds into the ground. Success depends on a combination of factors: the chosen planting time, soil condition, weather conditions, seed preparation and subsequent care. The best results are achieved by those who follow proven agricultural techniques and adapt them to their region and seasonal conditions.

Take soil temperature into account, do not rush into planting, prepare the seeds, do not neglect fertilisation and watering, and your beds will surely reward you with a generous harvest.