When it is really time, and not according to the «calendar», to plant cucumbers in open ground

Lovingly grown cucumber seedlings are already «asking» to be planted in the beds. But it is important to remember: this crop is very heat-loving and reacts poorly even to the slightest cold snaps. Therefore, it is better to play it safe and plant seedlings taking into account real weather conditions.

Many gardeners, when planting vegetable and herb seedlings, rely on the Lunar calendar, choosing the most suitable dates for work. There are quite a lot of such days in May and June.



But this tactic is not always correct, and sometimes frankly dangerous, because much more important than the position of the Moon and stars is the weather outside the window and its changes, which can both contribute to the good establishment of cucumbers and completely destroy young plants.

In cold May soil, cucumber roots cannot absorb nutrients and water, which slows down the growth of the above-ground part. Severe cold snaps, especially at night, contribute to stem rot.

And if a plant experiences stress for a long time, the fruits will become bitter because of cucurbitacin – a substance that cucumbers produce in response to unfavorable environmental factors.

In open ground it is better to plant early-ripening cucumber varieties, the harvest of which can be obtained already 35-50 days after emergence.
 

Cucumber seedlings sown in April are planted in open ground in the middle zone from mid-May to the second decade of June, when the soil temperature stabilizes at no lower than 16°C (at a depth of 10-15 cm) and the threat of return frosts has completely passed.

In Southern Europe (Italy, Greece, Spain, Portugal), cucumbers are planted in open ground already from mid‑April, when the soil warms up to about +15 °C.  

In Central Europe (Germany, France, Czech Republic, Austria, Hungary), planting begins in early May, after the threat of frost has passed.  

In Northern and Western Europe (Poland, Baltic countries, Belgium, Netherlands, United Kingdom, Scandinavia), cucumber seedlings are planted closer to the end of May — beginning of June, when stable warm weather sets in.  

Under film cover, bushes can be planted a little earlier – in the first half of May, after the soil has been pre‑warmed. Therefore, before choosing a planting date, it is worth first studying weather forecasts and only then looking at the planting calendar.  

A bush is ready for planting if it has grown 3-4 true leaves. The stem should be strong, 15-25 cm high. Overgrown seedlings tolerate transplanting and adaptation to a new place worse, so you should not keep plants on the windowsill or in the greenhouse for too long.



Another important point: before planting cucumber seedlings, they must definitely be hardened off. This should also be taken into account when choosing planting dates. Hardening begins about 10-15 days before the procedure, gradually lowering the temperature. You can open windows or take containers with seedlings to an unheated glazed balcony or greenhouse.

7 days before planting in the ground, young cucumbers are accustomed to outdoor conditions and placed for a short time in a shaded place. Every day the number of hours in the fresh air is increased. At the same time, for part of the time the bushes should be in the sun. A couple of days before planting, the seedlings are left outside for 6-8 hours.

Approximately 6-10 hours before planting, the seedlings are abundantly watered in order to injure the delicate root system less.
 

A place for planting cucumbers is chosen well-lit and without stagnant moisture. The soil should be loose, light, and of neutral acidity. Since autumn, a bucket of compost, humus, or manure, 100 g of wood ash, and 300 g of bone meal per 1 sq.m are added to the future cucumber bed. All this, except fresh manure, can also be added in spring.

As for mineral fertilizers, it is better to use complex formulations.

The cucumber bed is prepared several weeks before planting seedlings. If green manure crops were sown in the soil, they should be cut and incorporated into the ground (partially, to avoid excessive acidification).

To speed up the decomposition of organic matter, it is useful to water the soil with a solution of an EM preparation, for example, Baikal EM-1 or any product based on Trichoderma.

Cucumbers are best planted after cabbage, onions, garlic, beets, carrots, legumes, and nightshade crops.

The optimal distance between holes is 30-40 cm, between rows – 70-100 cm.

The depth and width of the hole should correspond to the size of the root ball. It is also worth leaving a little space for fertilizing. You can add to the hole (optional): a handful of biohumus or compost, onion husks, 2-3 tbsp of ash, mineral fertilizers.



You can install a trellis in advance on the cucumber bed, to which it will later be convenient to tie the bushes as they grow.

Before planting seedlings, each hole is watered with clean water or a biofungicide solution (Fitosporin-M, etc.). Each plant is removed carefully so as not to damage the roots, placed in the hole at soil level, and covered with earth, slightly compacting it.

Overgrown seedlings with a thin stem are placed at an angle of about 45 degrees so that roots form on the buried part of the stem and the plant is guaranteed to take root. If such seedlings are planted vertically, they will fall over because of stem weakness.

After planting, the beds are watered with warm water and mulched with organic matter: peat, compost, wilted mowed grass.

Watering with cold water and prolonged dry weather negatively affect cucumber development.

Bushes planted in the ground may need protection from direct sunlight on very sunny and hot days. The easiest way is to install stakes along the edges of the bed and stretch thin light-colored agrofiber over them.

Cucumbers also dislike strong wind and drafts. If the weather suddenly deteriorates, it is worth building a screen from nonwoven material on the windward side. Cut five-liter bottles with the neck removed, which are convenient to “put on” small plants, will also help save the plantings.
 

Also from mid-May, cucumbers can be sown directly into open ground. For this, it is better to choose early-ripening varieties and hybrids. It is useful to pre-germinate the seeds so that seedlings appear faster.

Pre-sowing disinfection will also be useful, for which hydrogen peroxide, chlorhexidine, or biofungicides can be used. Finally, it is worth treating the beds themselves to protect plants from root and crown rot.

Pelleted and coated cucumber seeds do not need to be germinated or disinfected – they already have everything necessary for protection.

The planting depth of cucumber seeds is 1-1.5 cm. 2-3 seeds are placed in one hole to increase germination. Later, weaker sprouts can be removed.

In order for cucumber seedlings to establish well and later produce a rich harvest, it is important to plant them in warm soil. If the ground is still cold, it should be warmed up, for example, with black film, and cucumbers should be planted under a spunbond cover stretched over arches.