University of California
UC Master Gardener Program of Sonoma County
Fennel
Growing fennel in the garden or taking advantage of the many wild plants in Sonoma County can give your culinary cabinet a boost in several different ways—through its pollen, oil, seeds, fronds, and root. Garden-grown fennel is the safest to use; it is not advisable to collect wild fennel growing close to a road and risk dangers from pollutants.
In the Garden
- Grow sweet fennel cultivars to harvest pollen, leaves, and seeds for herbal use. Grow cultivars of Florence fennel to harvest the bulbous base.
- Sow seeds of Foeniculum vulgare cultivars in warm, light, humus-rich soil and avoid heavy clay. Sow fennel in late winter indoors for transplanting 6 in. apart in April.
- Sow indoors and transplant in mid-summer for harvest in fall to avoid bolting in hot weather.
- Allow seedlings to develop sufficient root mass before transplanting. Root disturbance may cause bolting. Cover the soil with mulch for weed control and moisture retention.
- Keep soil bed moist until fronds are several inches tall then allow the ground to dry out about 1 in. below the surface. Overwatering causes rot.
- Encourage the large bulbous base of Florence fennel to form by clipping off any seed stalks that appear. Grow sweet fennel for stalks that produce pollen and seeds.
- Expect baby bulbs in about 2 months after planting; full size bulbs take longer, 2½ -3 months.
- Use a knife or sharp pruners to cut bulbs just above the large taproot. Prune off leafy stems to 1-2 in. on the bulbs before storing up to 2 weeks in the refrigerator. Store fronds for 1 week.
Fennel Pollen
- Harvest sweet fennel flower heads to retrieve creamy yellow pollen but leave enough heads intact to develop seed for collection later.
- Cut heads when pollen is warm and dry. For fresh pollen, shake or tap heads into a deep bowl to release pollen. For dried pollen, place heads tied together in a paper bag for a few days to dry in a warm place and wait for it to drop out.
- Alternatively, shake pollen from each plant in flower by bending stems into a bag and gently shaking pollen loose. Expect to harvest less than a half teaspoon from each flower head.
- Use pollen sparingly on food at first to determine its strength. Its flavor is similar to anise.
Fennel Oil
- Collect several blossoms and let dry 3-4 days before covering with 4-6 oz. of olive oil in a jar. Keep the jar air tight for 3-7 days on a countertop before using flavored oil.
- Clip ½ cup fennel leaves, crush, and mix with 2 cups olive oil. Store for 2 weeks on a countertop in an air-tight jar to allow leaves to infuse the oil. Strain through cheesecloth and store in a closed container.
- Crush 1-2 tablespoons of fennel seed, boil for 15-20 minutes in olive or another a light oil and cool. Leave seeds in the oil for a few days or strain immediately through fine cheese cloth. Store in a closed container.
- Expect a flavor sweeter than plain oils; try brushing on foods prior to grilling or sauteing; mix with a light vinegar in homemade salad dressings. Or use oil cosmetically.
Fennel Seeds and Fronds
- Harvest seeds on dry afternoons just after they turn brown. Winds may blow them away later.
- Chop or grind seeds or use whole as a flavoring in breads, pork and fish dishes, eggs, atop vegetables or sprinkled on pizza or in spaghetti sauce.
- Add fresh fennel fronds to salads by clipping off small feathery ends, not the stem, into tiny ¼-½ in. pieces. Add to soups, meat and fish dishes, atop roasted vegetables, eggs, and pizza or spaghetti sauce; or add to water when cooking beans or rice.
Fennel Bulb
- Bypass wild plants in favor of growing a variety of Florence fennel if you want to enjoy a root vegetable. Move mulch over the lower stem to blanch the bulb and increase its flavor.
- Harvest fennel bulbs as they mature by slicing through the root at the base with a sharp knife or pruners. If the bulb has grown larger than 3 inches in diameter, it will be tough.
- Store harvested bulbs up to a week in a plastic bag in the refrigerator, but for best flavor use immediately.
- Expect to find parsley worms, larvae of the beautiful swallowtail butterfly, feeding on a few stems. Larvae go through 5 stages from black/brown with orange markings and spines to smooth, pale green fat bodies with black and yellow stripes before pupating and emerging as yellow and black butterflies.
April 2022