Fennel is an attractive and delicious herb that is easy to grow. It prefers locations with full sun, and soil that is organically rich and drains well. It is relatively quick to grow, coming to full maturity in around 60 to 70 days. Leaves, bulbs and seeds are all commonly harvested for culinary uses. Fennel is delicious both raw and cooked, and its seeds are wonderful for cooking and baking. Leaves and bulbs can be harvested as soon as the plant is mature; seeds must be harvested later.
For Bulbs and Leaves
Wait until fennel plants have reached full maturity but have not yet produced flowers. You will know they are mature because they will be tall and leafy. Fennel plants can sometimes grow as much as 6 to 7 feet tall and may need staking, especially if it is very windy where they're planted.
Use your shears to snip the leaves and stalks gently, as often as you like. Try to choose different stalks to cut every time you harvest. Do not worry about the plant--it is very hearty. Unless you cut off all its leaves at once, it will simply grow more for you to eat later.
Dig the plant out of the ground using the trowel when you are ready to harvest the bulb. The bulb is the base of the plant where the stalks are growing from, just above the ground and the roots. The plant will not grow back after you have harvested the bulb, so be sure you have more fennel planted if you intend to continue harvesting. Cut the root off, scrub the dirt off the bulb and prepare in any of your favorite recipes.
Wait until the flowers have bloomed and begun to turn brown. When they start to look sad and slightly wilted, they are ready for harvesting.
Gather the seeds by either cutting off the flowers and shaking them over a bowl or brushing the seeds from the flower heads into a bowl while they are still on the plant.
Use the seeds fresh or dry. To dry them, spread them in a single layer on a sheet pan and allow to sit at room temperature in a draft-free place for a few days. Fennel seeds will keep for use in cooking or planting a new crop.