Most vegetables can be grown in the field from the beginning. However, plants with a long growing season and high thermal requirements, sown in the field, would not bloom and mature in our climate or matured only in late autumn. Such plants are grown from seedlings, under glass or foil covers.
The production of seedlings requires very good light conditions and temperatures suitable for different species. Meeting these requirements is very difficult in housing conditions. Sowing seeds and setting boxes even in the sunniest place, south window has no good effect. The plants grown under these conditions are flaccid, light green, their growing cycle takes too long, poorly adopt and as a result, despite careful cultivation, after planting into the ground, the yield is low. If no frame or foil tunnel is available, it is better to buy a ready-made seedling, produced in a greenhouse, crepe, dark green, young and well-fed.
Until recently, frames were the most widely used equipment for the production of seedlings – crates covered with windows. They are set on the ground surface permanently or transferred to the next cultivation places (the so-called. traveling chests). Recessing the box in the ground significantly reduces heat loss. Depending on the construction, single-pitched and gable frames are distinguished. Single-pitched frames have windows that incline in one direction, preferably south, thanks to which they heat up quickly, but at the same time they cool down quickly. More favorable thermal conditions prevail in the gable inspection, the windows of which face east and west – it heats up more slowly, but it stays warm longer.