The optimum period for successive cucumber planting in greenhouses is from July 15 to August 10.
If sowing is carried out too early (early July), extremely high summer temperatures may interfere with flower pollination, and young seedlings may suffer from heat stress or sunburn. Conversely, if sowing is delayed until late August, the plants may not have sufficient time to produce a full harvest before the onset of autumn cold weather (November).
It is recommended to sow the seeds first in individual cups or pots and then transplant 15–20-day-old seedlings into the greenhouse. This method saves time and protects young plants from excessive soil temperatures.
Seeds should be sown in cups between July 15 and July 25, allowing seedlings to be transplanted into the greenhouse in late July or early August.
After harvesting the previous crop, all plant residues should be completely removed from the greenhouse. The soil should then be thoroughly loosened and enriched with organic fertilizer together with phosphorus and potassium fertilizers.
Raised beds are recommended for cucumber cultivation.
Recommended bed dimensions:
Width: 70–80 cm
Height: 20–25 cm
Distance between beds (walkway): 60–70 cm
Seedlings may be planted in a staggered (checkerboard) pattern or in two rows on each bed.
The recommended spacing between plants within a row is 35–40 cm, allowing approximately 3–4 plants per square meter.
Dense planting should be avoided because good air circulation and sufficient sunlight are particularly important for autumn cucumber production.
Since temperatures remain high during August, a 50–60% shade net should be installed over the greenhouse to protect young plants from excessive heat.
Seedlings should be transplanted only in the evening after daytime temperatures have decreased.
The soil should be thoroughly watered immediately before and after transplanting.
Drip irrigation is considered the most effective irrigation method during this period because it maintains uniform soil moisture while reducing the risk of soil salinity.
For successive planting, it is recommended to use self-pollinating hybrid varieties that are resistant to high temperatures and fungal diseases, such as Orzu F1, Bern F1, Gunnar F1, and similar hybrids.
This is especially important because the number of insect pollinators decreases during autumn.
If direct seeding is preferred, the optimum sowing period is from July 25 to August 10, since plants grown directly from seed usually begin producing fruit 10–15 days later than transplanted seedlings.
Modern hybrid (F1) seeds, usually coated with green or red protective treatment, do not require soaking before sowing. They should be sown dry.
If untreated conventional seeds are used, they should be soaked for 12 hours in warm water or a Fitosporin solution before sowing. This promotes faster germination and improves disease resistance.
Seeds should be sown at a depth of 1.5–2.0 cm.
Planting too deeply may reduce oxygen availability and delay germination, while shallow planting may result in drying of the seeds.
The spacing between planting holes should be 35–40 cm.
Place one or two seeds in each planting hole. After germination, remove the weaker seedling, leaving only the strongest plant.
Maintaining adequate soil moisture is the most important factor for successful establishment.
During August, both the soil and air temperatures remain very high. If the soil dries out after sowing, germinating seeds may die quickly. Therefore, the soil should remain consistently moist—but not waterlogged—until seedling emergence.
Drip irrigation is highly effective for maintaining the required soil moisture.
After irrigation, the soil should be loosened regularly to prevent the formation of a hard surface crust, allowing seedlings to emerge easily.
Applying a thin layer of well-decomposed farmyard manure over the planting holes is also beneficial.
The use of a shade net over the greenhouse is essential to prevent excessive soil heating and protect the seeds from heat damage.
Direct seeding greatly simplifies cucumber production; however, during the first five days after sowing, particular attention should be paid to maintaining adequate soil moisture.
