Cucumber cultivation technology on straw substrates in greenhouses

Cucumber cultivation on straw substrates

Cucumber cultivation on straw allows for high yields in greenhouses without technical soil heating. A substrate of wheat straw, harvested from fields not treated with herbicides, provides an optimal temperature regime and enriches the air with carbon dioxide. In practice, two methods of preparing straw beds are used.

• Yield increase on straw — 3–5 kg/m²
• Temperature of straw substrate — 25–27 °С
• Soil temperature with technical heating — 20–21 °С
• Loose straw consumption — 50–200 t/ha

With the classical method, 2–3 weeks before planting transplants, a layer of loose straw 30–40 cm thick is laid in the greenhouse. Then, the substrate fermentation process is initiated using hot water and mineral fertilizers. This allows for rapid warming of the bed before planting the crops.

1. Water the straw with hot water (50–60 °С) at a rate of 1.5–2 l per 1 kg of substrate.
2. Apply dry mineral fertilizers: first, wash in ground limestone and superphosphate with a hose, then 25% of ammonium nitrate, and finally the remaining nitrate and potassium sulfate.
3. Wait for the straw to heat up (the temperature inside the layer rises to 40–50 °С) and subsequently cool down to 27 °С. This usually takes 7–10 days.
4. Plant the transplants directly into the straw or into a 5–10 cm thick layer of nutrient mixture pre-laid on top of it.

When growing cucumbers on straw, approximately twice as much water is consumed as in ordinary soil. High humidity is necessary to maintain the vital activity of the beneficial microflora in the substrate. During the growing season, plants are top-dressed every 10–12 days with a mixture of ammonium and potassium nitrates at a rate of 0.75–1 g of each fertilizer per 1 l of water.

There is a more economical technology with a straw consumption of 50–60 g per 1 centner. 10–15 days before planting, furrows 30–35 cm wide and 15–20 cm deep are dug. Straw and fertilizers are placed on the bottom, then watered and covered with a 6–8 cm layer of soil. The surface of the formed bed is mulched with straw, which protects the soil from crusting and erosion, eliminating the need for loosening.

Agrotechnology, prevention of fruit set shedding, and green conveyor

One of the common problems in growing parthenocarpic cucumbers is the cessation of development and shedding of fruit sets. This occurs due to the weakening of parthenocarpy caused by environmental stress factors. Parthenocarpy is particularly weakly expressed in the lower part of the stem.

To rectify the situation, growing regimes are optimized and a high level of agrotechnology is maintained. If there is rapid leaf growth at the expense of fruiting, sex regulators are used. Foliar applications help redirect nutrients to the fruits.

Harvesting is carried out in the second half of the day when the cucumbers reach the standard size. At this time, the fruits contain a minimal amount of nitrates. Adherence to the technology allows for harvesting a consistently high yield in different types of greenhouses.

An uninterrupted supply of fresh produce from May to September can be organized through a combination of different types of covers and correct planting times for transplants. The use of frameless plastic covers allows for accelerating maturation by 10–15 days compared to regular sowing in the ground. To extend the fruiting period until autumn, cultivars with different maturity dates are used.

How to avoid peronosporosis using timing and covers

The main obstacle in cucumber cultivation remains peronosporosis (downy mildew). Contrary to the popular belief about the influence of radiation or acid rain, the pathogen is activated by climatic factors: sharp temperature fluctuations between day and night and high humidity during the growing season. Ecological pollution only weakens the plants, intensifying the damage. To save the harvest, the agronomist needs to shift fruiting to an earlier period.

The use of early-maturing cultivars with concentrated harvest allows for obtaining marketable products before the mass spread of the disease. For longer fruiting and work in sun-heated film greenhouses, intensive-type hybrids are chosen. They combine genetic resistance to pathogens with high productivity and are suitable for both the fresh market and processing.

• Storage of market quality for cultivars Lyalyuk, Severyanin, Vityaz — 7–10 days
• Period from emergence to first harvest for cultivar Lyalyuk — 35–40 days
• Yield of cultivar Dzherelo — 4–5 kg/m²
• Yield of hybrid Smak F1 — 6–10 kg/m²

Selection of cultivars and hybrids for protected and open ground

For different technological schemes, cultivars and hybrids are selected that differ in ripening periods, stress resistance, and fruit quality. High efficiency in film greenhouses, as well as in warm ground, is shown by F1 Slobozhansky and F1 Ksana hybrids (Rodnichok type). For late harvests up to frosts, hybrids of the Nezhinsky cultivar type are used, capable of fruiting in partial shade.

When choosing Samorodok F1 and Smak F1 hybrids, plantings can be placed in partial shade under trees, using their branches as a natural trellis. The thin skin of the Samorodok F1 hybrid fruits ensures fast penetration of brine, thanks to which cucumbers retain their density and crunch when preserved. The Smak F1 hybrid retains its marketability in fresh form even when overripe, and its young fruits 5–7 cm long are suitable for high-quality pickling.

from late May - early June. For this purpose, film covers and early-maturing cultivars and hybrids are used. It is better to take not one cultivar, but several — this contributes to good pollination and fruit set. It is advisable to place covers in screens made of tall-stemmed crops (corn, dill), especially in areas where strong winds blow. Screen plants are planted across the direction of the prevailing winds.

The plot is well fertilized. In the autumn, during digging, manure is applied — 10—20 kg, ammonium nitrate — 20 t, superphosphate — 30—40 g, potassium sulfate or potassium magnesium — 10 g per 1 m². Cucumber is one of the few crops that prefers manure over humus.

For planting, 20—25-day-old transplants are used, which are grown in 8x8 cm pots. The transplant method is more effective than sowing seeds under a cover, as it allows for obtaining an early harvest 10—14 days earlier. Transplants are planted when the soil temperature at 8 a.m. at a depth of 10 cm is at least 12—14 °C. As a rule, this happens in the third ten-day period of April. For better soil warming, film covers are installed 10—15 days before planting.

Planting is carried out in the second half of the day or in overcast weather to avoid wilting of the plants. Cucumber transplants are planted on both sides of the furrow in a staggered pattern, tilting the plants alternately to one side and the other. With a cover width of 80 cm, the distance between the two rows formed during planting is 40 cm, and between plants in a row — 25—30 cm.

During planting, 200—250 g of organic-mineral fertilizer is applied into the hole. The following components are used for this:

If "Biocom" or "Biogumus" is available, you can limit yourself to these fertilizers at a rate of 100 g per hole. It is good to mulch the soil around the bushes with pieces of cow manure and water them regularly. The released carbon dioxide contributes to an increase in yield.

Irrigation regime and plant formation:

• Water the cucumber only with warm water (22—25 °С). After 3—4 days, it is good to use herbal infusion for irrigation.
• Before flowering, irrigations are withheld, which contributes to an increase in female flowers, and after flowering, irrigations are increased, avoiding excessive soil moisture.
• Plants should bloom when the assimilation apparatus is well developed. But if it happens that you are planting overgrown transplants with a flower, it must be removed; otherwise, the forming fruit set will inhibit the growth of the plant and fruiting.
• Until the vine forms, after each irrigation, the soil is loosened to 2 cm (it is better to do this by poking with a pitchfork).
• For proper use of the area, vines are spread out and pinned to the moist soil. After roots appear, soil is added, thereby replacing soil loosening.

From 9 to 12 o'clock, before the bees start arriving, manual pollination of cucumbers is carried out using a soft, thin brush and a match with cotton wool.

Plants are fertilized once every 7—10 days with fermented cow manure, diluted in a 1:8 ratio, or poultry manure — 1:12.

It is desirable that the containers with cow manure stand under the cover so that the air is enriched with carbon dioxide. Cucumber likes foliar top dressing, especially when overcast weather gives way to clear weather, and the plant needs to be given "first aid" at this time. Thus, when adding a surfactant — urea — the absorption of nutrients through the leaves proceeds more actively.

During the growing season, the daytime air temperature under covers should be 25—28 °С. Therefore, special attention is paid to ventilation. To do this, the film is lifted first from the ends, and then from the sides of the frame, on the leeward side, securing it this way from 10 to 16 hours. Then it is lowered to preserve the heat accumulated during the day. In overcast weather, covers are not ventilated. Subsequently, the film is lifted from both sides and secured at the ridge of the cover.

After the onset of consistently warm weather, when the night temperature no longer drops below 16 °С (end of May), the film or frame is removed. This must be done gradually (preferably in overcast weather) so that the plants do not burn. Before removing the film, the soil must be watered.

It is recommended to harvest daily, as this increases the productivity of plants and prevents the cucumbers from overgrowing. If you want to salt gherkins or pickle baby cucumbers, you need to harvest them twice a day.

Supports for cucumbers Many gardeners direct vines to nearby supports — a fence, specially planted corn or sunflower plants. You can combine growing plants under a cover with subsequent tying of plants to trellises. I do it this way. I plant plants in an ellipse with diameters of 1.6x1.2 m at intervals of 25 cm in order to tie them up later to form a tent. To increase relative humidity and reduce overheating, I place a container of water. After 3 weeks, I remove the film and tie them to the structure that forms the tent. In the center, I bury a pole with a wheel at the top, to which I tie the upper end of the twine. You should not overstretch the twine so as not to pull the plant out by the root. You should not tie the twine knot tightly on the stem, as the stem grows, and the twine will cut it. It is best to tie the lower part of the twine to a peg and stick it into the ground, and wrap the stem around it as it grows.

I water the soil along the furrows at a distance of 30 cm from the plant, since the cucumber does not tolerate watering at the root well (the soil washes away after watering, the root system is damaged). The cucumber really likes sprinkling with warm water. But I usually finish watering before 17 o'clock so that the leaves have time to dry before nightfall. A cow manure solution ferments in a container, which I use to regularly top dress the plants.

You can use heated hotbeds. In this case, it is important to plant the cucumber at least 10 days earlier than you would in an unheated hotbed or under a cover, i.e., in mid-April. The planting time is crucial for obtaining an early harvest. Special attention must be paid to the irrigation regime, as loose soil dries out faster. Otherwise, the cultivation technique is as described above.

A method for obtaining a cucumber harvest 10-75 days earlier than usual

To get a cucumber harvest 10—15 days earlier than usual, use frameless covers. On the garden bed, make furrows 90—100 cm apart. In the third ten-day period of April, sow the seed at the bottom of the furrow, water it, and cover it with perforated film. Leave 8 plants per 1 m?. After 3—4 weeks, remove the film, and in the second half of June, start harvesting the cucumber. Remember that cucumbers should not be returned to the same spot earlier than in 4 years. You can grow melon, watermelon, summer squash, and many other crops in the same way.

The method of growing cucumber in polyethylene bags allows for the creation of an optimal regime for the root system. Take a large polyethylene bag and fill it with a mixture of soil and semi-decomposed manure in a 4:1 ratio; add mineral fertilizer: 1 tbsp of nitroammophoska per bucket of mixture. Cut the bottom of the bag to create a tube filled with nutrient mixture. Place it horizontally in a hole previously dug to the size of the tube (the top of the tube should be 10 cm below the ground level). Make 4 holes in the tube, where you sow the cucumber seed or plant the transplants. In this volume, it is easier to provide the relatively small cucumber root system with nutrients and moisture so that it reaches the soil level. Depending on the weather and plant development, this will be enough for 3—5 days. This method accelerates the arrival of produce and increases the yield. It is good to use it in a wind-protected area, perhaps under an apple tree. The plants will climb up a trellis directly to the branches of the apple tree, which will provide them with a good microclimate and the plants will be less prone to disease.

The "khalabudka" method has its advantages. It is described in detail at the beginning of the book (section "Insulated soil").

A complex of measures for the protection of cucumber from downy mildew.

The first signs of this disease are oily green spots that eventually turn brown, causing the leaves to dry out. Under conditions favorable for the disease—low temperatures combined with high humidity and night fogs—the incubation period lasts 3—4 days. Inside the affected tissue, spores are formed that overwinter in plant debris. The infection is spread by wind and clothing. In addition to using film covers and growing early cultivars with concentrated yield, which helps to "get ahead" of the infection and harvest before the disease can occur, the complex of measures includes: — maintaining a high level of agricultural practices with the use of crop rotation and not returning cucumbers to the same place earlier than in 4—5 years; — using the transplant method;

— using trellised crops; — observing the specifics of irrigation and top dressing regimes; — preventive spraying; — seed treatment.

Nowadays, tying cucumbers to a trellis—a wire stretched on supports—is widely used. In this case, less liquid moisture forms on the underside of the leaf, which contributes to disease development, and the plants are better ventilated by the wind. It is possible to combine growing plants under covers with subsequent tying to a trellis.

You need to experiment yourself to understand which form of trellis to choose. Whether you use a tent or stretch wire in rows. The second method provides better aeration, which prevents the development of disease. However, such an approach contradicts the biological requirements of the cucumber, which does not like air movement. Or perhaps, as a compromise, a tent would be good?

Practice has shown that the trellis method of cultivation is justified only in areas protected from the wind. It is recommended to gradually remove the lower leaves at a height of 25—30 cm from the soil surface.

Infection with downy mildew is promoted by the presence of liquid moisture on the underside of the leaf (for at least 6 hours). To avoid this, it is best to irrigate the cucumber in the morning, rather than in the evening, so that all moisture has time to evaporate.

Foliar top dressing and protection of cucumbers from diseases

To increase the resistance of plants to diseases and stimulate the rapid growth of lateral shoots, regularly carry out foliar top dressing. Such a technique promotes the rejuvenation of the bushes and improves fruit set. Spraying should be carried out in cloudy weather or in the early morning hours to avoid leaf sunburn.

• Treatment frequency — once every 10–15 days
• Waiting period after Bordeaux mixture — 5 days
• Application rate of potato sprouts — 2 kg per 10 l of water

At the first signs of downy mildew, treatment with whey provides good results. To prepare the solution, mix 3 l of whey with 7 l of water and add 1 teaspoon of copper sulfate. To combat downy mildew and bacteriosis, where small brown ulcers first form on the leaves, and then the leaf tissue dries out and crumbles, Bordeaux mixture is traditionally used.

1. Dissolve 100 g of copper sulfate in a separate container (it is better to use hot water).
2. In another container, dissolve 100 g of slaked lime and strain the resulting solution.
3. Cool the copper sulfate solution until cold.
4. Slowly pour the cold copper sulfate solution into the strained lime, stirring the mixture constantly and vigorously.
5. Bring the resulting volume to 10 l with water.

In the practice of vegetable growers, an infusion of potato sprouts is used to increase resistance to downy mildew and prolong fruiting. Sprouts are harvested in the spring during tuber storage in a dark room. Method of preparation and application of the infusion:

• Pour 10 l of hot water over 2 kg of potato sprouts.
• Infuse the mixture for 2 days.
• Dilute 2 l of the finished concentrated solution 4 times with clean water.
• Use the diluted solution for soil irrigation and plant spraying.