How to Grow & Use Fennel

Plant fennel in a location that receives six to eight hours of sunlight daily, and in soil that drains well. Mix a 2-inch layer of compost and 3 tablespoons of 14-14-14 granular fertilizer into the top 6 inches of soil per 10 square feet of bed.

Transplant the fennel seedlings at the same depth they were growing in their seedling containers. Space the plants 8 to 12 inches apart in rows spaced 18 inches apart.

Irrigate once weekly and provide 1 to 2 inches of water each time, or enough so the soil is moistened to a 6-inch depth. Water near the base of the plants so the moisture can soak deeply into the soil instead of evaporating quickly off the foliage.

Fertilize a second time with a 21-0-0 nitrogen fertilizer when the fennel plants begin to form bulbs at their bases. Sprinkle 3 tablespoons of the fertilizer down every 10 feet of fennel row, placing the fertilizer 6 inches away from the bases of the plants. Water immediately after application so the nutrients soak into the soil.

Pull any weeds that grow between the developing bulbs promptly so they don't become established and rob moisture and nutrients from the fennel. Spread 1 to 2 inches of mulch between the plants to help prevent weeds, if desired.

Check the plants weekly for signs of insect damage from aphids, thrips or cabbage moths. Damage can appear as chewed leaves, sticky residue or leaf spots from feeding. If necessary, spray the underside of the foliage, where the pests usually feed, with an insecticidal soap.

Trim off the fennel leaves at any time for immediate culinary use. Cut the bulb off at soil level when it grows to 2 to 4 inches in diameter. Slice the bulb into wedges or strips for use as a cooked vegetable in sauces, salads or soups.