Who with early kohlrabi on large, value quickly developing tubers, must give the plants enough space.
Planting too densely delays tuber development considerably. Only where the developing leaves are offered plenty of air and light, one can hope for rapid development and tender tubers. The same applies to the sometimes widespread method of double planting, where two plants are placed in a planting hole. Solitary kohlrabi reaches the harvestable tuber diameter faster, than is the case with the double plants. For this reason, early kohlrabi needs a space of at least 25cm x 20cm under glass and foil and 25cm x 25cm outdoors. Who does not have to save a lot with the space, should better choose a row spacing of 30cm.
The depth of planting is also decisive for tuber development. Kohlrabi must be planted flat, because otherwise the development of the tuber is inhibited and does not proceed normally. You can only plant so deep, that the upper roots are just covered with soil, where firm planting prevents falling over. Planting too deep delays tuber development and leads to the formation of elongated tubers or even to bolting.