After a couple of mammoth posts, a shorter one, partly because fennel is not such an important crop and is relatively simple to grow. But many people have issues with growing it. There is one vital thing to know and then it is not as bad as often made out.
The sweet, aniseed flavour of Florence fennel is not to everyone’s taste. I love it. It is an annual form of the common herb fennel and it grows quickly. The plants must never receive a check to growth once they are growing so they must be kept moist throughout the growing season or they will bolt. In hot areas a slightly shady spot can be beneficial but in any case it is best to add plenty of organic matter to the soil before planting.
Spring-sown crops almost always bolt and you can sow from May to July. I would stick to June onwards but even if plants do run to seed you can still use the foliage and flower stems for flavouring.
Sow in rows 1cm deep as thinly as possible and thin to about 15cm apart once you are sure the seedlings are large enough to survive. Thinnings can be used for salads and flavouring too. You can harvest as soon as the ‘bulbs’ are as big as you like but use them before the first harsh frosts of autumn because they are damaged by frost.