Growing cucumbers in the greenhouse

What are the advantages of growing cucumbers in a greenhouse?

In the habitats cut off from the environment made of foil or glass in one Glasshouse heat, light and humidity can be regulated particularly well. This makes it possible to plant plants there that would not feel very well under the changeable conditions of the German weather.

That also applies to them Cucumber (Cucumis sativus) to. In a greenhouse, she can start sowing cucumber seeds a few weeks earlier, in early May. In a heated greenhouse or a warming hotbed, sowing can even start as early as April. This also extends the season in which cucumbers can be planted until October, when it is still warm enough.

It is a good idea to set up sticks in the greenhouse and stretch cords on which the plants can climb vertically. This saves space and simplifies care and harvesting.

If it is particularly hot or sunny after planting, the cucumber plant should be shaded. Even in midsummer, when the temperature is over 30°C, linen cloths or fleece should be attached to the roof struts to protect the plants from sunburn, burn heads and heat stress.

Thanks to the roof, the cucumber plants in the greenhouse are also protected from bad weather and wind. As a result, there is no need to worry about storm-related damage or long periods of dripping water that could cause fungal diseases.

In the greenhouse, the cucumbers are also protected from larger pests, such as snails and protected from voles. Smaller pests, such as aphids (Aphidoideae), still find their way to the plants, but it makes sense to use smaller beneficial insects to combat them. Examples of this are the seven-pointladybug (Coccinella septempunctata) or lacewing larvae (Chrysoperla carnea).

What types of cucumbers are suitable for growing in a greenhouse?

There are many varieties of cucumbers. They differ in growth, fruit shape and color as well as their robustness.

Almost any variety can be grown in a greenhouse, but cucumbers are a particularly good choice, as these long, delicate fruits don't thrive outdoors.

The varieties that have a particularly good tolerance and resistance to the diseases that frequently occur in the greenhouse are excellently suited.

• Arola: This robust snake cucumber with a thicker skin and light spines is particularly resilient. Since the fruits are mainly formed on the side shoots, they should not be parched.
• Burpless Tasty Green F1: This highly resistant strain is also available commercially. It forms 25 - 30 cm long cucumber fruits and can be harvested about 80 days after sowing.
• Helena: Even without pollination, it forms long, straight and smooth fruits.
• Dutch yellow cucumbers: This unusual variety can be harvested as early as June if cultivated early, cucumbers that are about 20 cm long and have a purely yellow skin with creamy-white flesh.
• Saiko: The mildew-resistant cucumber with a high, early yield forms cucumber fruits up to 40 cm long that are slightly prickly, curved and bitter-free.
• Saladin F1: This cucumber is ideal for greenhouse cultivation with fruits up to 35 cm long. This variety is particularly resistant to bacterial leaf diseases, leaf scorch and also fungal diseases.

8 tips for growing cucumbers in the greenhouse

1. preparations 

Young cucumber plants are particularly sensitive to low temperatures. If the small cucumbers are to be planted at the end of April / beginning of May, a heater is required that keeps the temperature at at least 12 to 14°C at night.

Without heating, cucumbers can be planted only in mid-May.

The soil for cucumbers in the greenhouse should be loose, crumbly and humic. The humus content is increased by applying 3 to 5 liters compost per m2 before planting is improved and the first fertilization is applied at the same time

2. Correct plants

Before planting, the plants should be at least approx. be 20 cm high. Only the best young plants are selected for cultivation in the greenhouse.

They should get the warmest spot in the middle of the bed. 1-2 cucumber plants can be planted per square meter. When planting, 60 g of horn meal and 100 g of potassium magnesia should be given per square meter. Between the young plants it is a good idea, for example salad to plant. However, any undersowing or underplanting must be taken into account when fertilizing and watering.

3. Cucumbers like it warm underneath

Black mulch film on the ground increases the temperature in the root area. The film should be perforated or slit so that you can pour over the film and air can be exchanged with the floor.

4. Training and care in the greenhouse

Wire can be stretched under the greenhouse roof so that the plants grow vertically upwards. Strings are then lowered to the cucumber plants and these strings are fastened below the cotyledons with a loop that must not tighten.

The cucumbers are carefully twisted into the twine from week to week.

At the upper end, where the cord is attached to the guy wire, you should be able to slack off some of the cord if necessary. As soon as the cucumber plant reaches the greenhouse roof, its top is cut off.

A maximum of 6 cucumbers are left on the main stem of the plant, with the lowest one hanging at least 60 cm above the ground. The side shoots are also removed up to a height of 60 cm. The other side shoots are shortened and only one or two fruit buds are left.

5. The right climate

Cucumbers grow best in a greenhouse. They love it protected and warm at 20-25°C. However, the humidity should not be too high, because when the temperature drops, fungal diseases can quickly develop. Furthermore, care should be taken to ensure that air is exchanged regularly.

6. watering and fertilizing

Despite a high water requirement, it is important to ensure that no waterlogging forms. In the greenhouse, general extreme situations should be avoided, in terms of heat as well as water. When stressed, there is a risk that the young fruit will deform or even die.

When fertilizing, it should be noted that cucumbers are sensitive to lime, chlorine and salt, so organic ones are good for them fertilizer good.

If the plants need more, e.g. B. because the variety is particularly vigorous, you can fertilize once or more with a liquid fertilizer or an organic fertilizer.

Indications of a general lack of nutrients are the brightening of the youngest leaves and stunted growth, which cannot be attributed to cold, temperature fluctuations or watering errors.

7. Keeping cucumbers healthy

If the humidity is not too high at night and the temperatures are appropriate, it is not rocket science to keep the cucumbers healthy. Nevertheless, they are often attacked by pests such as spider mites, aphids and thrips. To avoid this, the plants, leaves and fruits should be examined frequently. The undersides of the leaves in particular should be checked. If the pests are discovered early, they can be combated with beneficial insects or other environmentally friendly plant protection measures.

8. Harvesting and Storage

The cucumbers are ripe when the skin feels smooth. They are harvested by cutting off the stalk above the fruit with a knife. They are best stored at approx. 13°C.

Cucumbers are therefore very well suited to be planted in a greenhouse, as the heat here is appropriate can be regulated, the beds can be arranged to fit and the cucumbers can be kept extra warm underneath can become. Species that are particularly good are Arola, Burpless Tasty Green F1, Helena, Dutch Yellow, Saiko, and Saladin F1.

With the right care and attention, every hobby gardener can enjoy cucumbers from their own greenhouse.