Each type of plant has an optimal germination temperature at which the seeds quickly grow strong sprouts. At these temperatures germinate vegetable seeds.
If you want to harvest delicious vegetables as early as possible, you should start sowing seeds early. You can sow the first vegetables as early as March. Especially for species that set flowers and fruits late, such as artichokes, peppers and eggplants, you should not wait too long. Fruiting vegetables from warmer regions and exotic fruits, for example Andean berries, require high growing temperatures. Cabbage and leeks have lower requirements, leafy vegetables such as spinach and chard, but also the robust root vegetables like it rather cool. Lettuce in particular is reluctant to germinate at temperatures above 18 degrees Celsius.
If you have sown wide cubes in seed trays, the seedlings are “pricked out”, i.e. transplanted into individual pots, as soon as the first leaves sprout. Then lower the temperature slightly (see table). The following applies: the less light, the cooler the further cultivation, so that the young plants grow more slowly and remain compact. If the temperatures in the cold frame or greenhouse fall below the above values, the risk of bolting increases, especially in the case of kohlrabi and celeriac.
Germination temperatures for vegetable seeds
|Optimal germination temperature||Vegetable species||Remarks|
|Cool preculture (12 to 16 °C)||Broad beans (broad beans), peas, carrots, lettuce, parsnips, radishes and|
|After germination at 10 to 20 °C|
(16 to 20 °C)
|Cauliflower and broccoli, chicory, kohlrabi, tuberous fennel, chard, May and fall turnips, leek, parsley, beet, chives, celery, onions, savoy cabbage||After germination at 16 to 20 °C|
(22 to 26 °C)
|Andean berries, eggplants, bush and pole beans, cucumbers, melons, pumpkin and zucchini, peppers and hot peppers, tomatoes, sweet corn||After pricking out at 18 to 20 °C|
The sowing soil should be fine-grained and low in nutrients. You can get special propagation soil in stores, but you can also make such a growing soil yourself. Spread the seeds evenly over the soil. Large seeds, such as peas and nasturtiums, can also be sown individually in small pots or multi-pot plates, while fine seeds are better sown in seed trays. Press seed and soil lightly so that the germinating roots make immediate contact with the soil. On the seed package you will find information on whether the plants are dark or light germinators. So-called dark germinators should be sprinkled with a thin layer of soil, while the seeds of light germinators remain on the surface.