Worth growing for its pretty foliage alone, florence fennel also offers the bonus of its delicious, white, aniseed-flavoured bulb. It’s a little tricky to grow, but definitely worth a try. Has a relatively short growing season – will be ready to eat in 4 months.
It's a Mediterranean crop that will get confused and bolt if exposed to fluctuating or low temperatures. Sow in late May and again in late June (as insurance against bolting and poor germination). Fennel seedlings are very sensitive to root disturbance – sow a couple of seeds in each module of a seed module tray about 1cm deep. If more than one germinates in each module, remove the weaker one.
About a month after sowing (when the seedlings are hardy), it’s time to plant them out. If the temperatures are still low outside, you can delay planting by a few weeks by potting them on in to individual pots. Harden off the seedlings well before planting out. Grow in full sun. Add well-rotted manure or compost to the soil in late spring. Space the plants 35cm apart. Water, mulch and weed. If you're feeling particularly attentive, earth up the stems as they swell to blanch and sweeten them.
Expect bulbs to be ready 14-16 weeks after sowing (the bulb should be 7cm across). Cut the bulb off at ground level. Further, feathery shoots will appear which can be used as celery/dill-flavoured seasoning in the kitchen. Snip the leaves off the bulb – if you leave them on, they draw the moisture out of the bulb. The bulb is best eaten sweet, ripe and fresh (try it raw in salads) but it will also keep for several days in the fridge.
Slugs are a problem at seedling stage. Cold spells and dry weather will cause bolting.