Pre-grown cucumbers flower earlier and therefore set fruit earlier. However, cucumbers do not tolerate pricking out well and sometimes the stem breaks when handling the cucumber plant. This does not have to be the case: Here are some tips on how to grow cucumbers in advance and what you should then bear in mind when planting them.
Why grow cucumbers in advance at all?
There are advantages to growing cucumbers in advance. Cucumbers, like tomatoes and peppers, take quite a long time from germination to harvest. By pre-sprouting, you give the cucumbers a jump-start that will benefit them when you plant them out.
If you decide to grow seeds instead of buying young plants, you often have a wider range of varieties at your disposal. This can be a decisive factor, especially if you have special location requirements and choose between outdoor and container planting.
Pre-planting cucumbers can be done in a greenhouse or at the window and takes up to four weeks. A good start is therefore the end of March or beginning of April – however, sowing should not be done too early. Outdoor cucumbers should not be sown before mid-April so that the young plants do not grow too large indoors or under glass. They are not allowed in the beds until mid-May.
Grow cucumbers in advance: How to proceed
Skilful pre-growing of cucumbers
1) Make sure there are drainage holes in the bottom of your seed pots or use organic seed pots. 2) Fill them only halfway with growing soil as substrate. Fill them only halfway with growing soil as substrate. 3. Now place one or two seeds in each pot. 4. Cover the seeds with about one centimetre of substrate. 5. The germination period is about one to two weeks (depending on your cucumber variety). 6. When the seedlings are just peeking over the edge of the pot, choose the strongest seedling and remove the other one. Carefully fill the seed pot with substrate. 8. As soon as the cucumbers have developed four leaves, plant out.
If you want to bring forward different varieties of cucumber, it is worthwhile to use planting tags, as the seedlings cannot be distinguished visually at first. The seedlings need a lot of light and warmth. The temperature should be at least 20 degrees Celsius for germination. On the windowsill, the pots can be placed on an insulating base. In a small greenhouse on the windowsill, the cucumber enjoys good conditions when growing up. Alternatively, a bag or foil can be spread over the pot. This helps to speed up germination. However, there is also a risk of mould, so lift the foil daily and let the air circulate.
Always keep the soil moist during the pre-growing period of your cucumber by spraying it with water in the early stages. From the second week, you can then also water carefully – preferably from below. Once the seedling is visible, no more covering is necessary. Now you should provide sufficient light. However, make sure that the temperatures are not too high in order to prevent the plants from yellowing. Once the plants have grown a little, you have a choice: only one strong seedling remains in the pot. If both seeds do very well in the seed pot, one of the plants can be transplanted. Filling in additional soil afterwards will lead to the formation of so-called adventitious roots, which will ensure better rooting when the plants are planted out.
Hardening off young cucumbers
Young plants are sensitive to cold. Before planting out, you can put them outside for a few hours every day. Please do not place the plants in full sun right away, but proceed step by step. In this way you will get the young plants used to direct sun. By acclimatising the plants, you prepare them well for the conditions outdoors and thus round off the advantage of pre-growing cucumbers. The young plants can then be moved into the bed or into a planter with a capacity of at least 20 litres after the Ice Saints in mid-May. Plant the pre-cultivated plants so deep that the cotyledons are covered with soil.
Crop rotation in the bed or greenhouse is important: Cucumbers should accordingly only be planted in the same place four years apart. The soil in the greenhouse may need to be replaced. Cucumbers are heavy growers and need a lot of nutrients. Before planting, you should apply plenty of compost.
Direct sowing of outdoor cucumbers
The first outdoor cucumbers can be sown from the end of April, provided the soil is at least 10 degrees Celsius. Fleece or foil help well against late frosts, which threaten until mid-May.
Since cucumbers take up a large bed but develop slowly at first, there is still room at the edges of the bed for lettuce or other fast growers. They have long been harvested by the time the cucumbers sprout. Sow the cucumbers in a single row in the middle of the bed. A distance of at least 40 cm is required within the row.
Use gaps in the bed at the beginning for other crops
Until cucumbers, but also pumpkins and tomatoes take up the full area, lettuces, radishes, early radishes, Asian lettuces, baby carrots, chervil and cress will ripen loosely next to them in mixed cultivation. If you only have a few weeks available, use the gaps to bring forward cabbage, lettuce or chard seedlings.