How to Grow Fennel – A Guide to Growing Fennel
Fennel has two main types – common fennel, and florence fennel – which are not to be confused.
Florence fennel is grown for its swollen bulb and eaten as a vegetable, whereas common (or sweet) fennel is a tall (up to 180cm) perennial herb grown for its seeds and feathery foliage and is often used as a substitute for dill. Common fennel does not produce a bulb.
Both types of fennel have an aniseed or liquorice taste.
Recommended Varieties of Fennel
- Florence fennel varieties include Amigo (RHS Award of Garden Merit)
- Common fennel is usually green-leaved, but purple/bronze leaved varieties can also be found
Pests and Problems Affecting Fennel
- There are few pests which attack fennel, apart from aphids
- It can bolt if it gets too dry or too cold, so do not sow too early and ensure it is kept well-watered
Sowing & Growing Fennel
- Both types of fennel need a sunny, well-drained soil which has had humus or other organic matter added during the previous winter.
- Sow Florence fennel seeds successionally between May – June, 2cm deep in rows 38-45cm apart, thinning to 30cm between plants as they grow larger
- If you wish, you can earth the bulbs up when the bulbs are the size of golf balls in order to make them more white
- Water when dry
- Individual fennel plants can also be grown in large pots
Harvesting, Eating & Storing Fennel
- The leaves can be harvested whenever desired
- To harvest the seeds from common fennel, allow the plants to flower and fade, and remove the seeds when the seed heads are fully ripe. The seeds are said to help digestion and are often found in recipes for oily fish.
- The bulbs of florence fennel should be ready for harvest in August-October when they are no larger than the size of a tennis ball. Cut just above soil level and underneath the base with a sharp knife. Remove the larger leaves from the bulb.
- Florence fennel can be eaten raw, braised, casseroled or boiled. It is a good source of folic acid, potassium and vitamin C.
- The bulbs can also be frozen.
- Do not grow fennel and dill close together as they may cross-fertilise and thus affect their taste
- Grow fennel away from other plants as it is known to inhibit some plants’ growth