Planting Fennel
Fennel is a cool season herb in the Apiaceae family. Getting the timing right is the difference between a strong stand and a disappointing one, so the windows below are given relative to your own last spring frost and first fall frost rather than a generic calendar date. Look up your local frost dates and count back or forward from there.
Transplant young plants outdoors 0–2 weeks before your last frost — Fennel tolerates cool conditions and benefits from an early start.
You can sow Fennel directly into the garden 0–2 weeks before your last frost.
For a fall crop, sow 10–12 weeks before your first fall frost so plants mature as the weather cools.
Fennel can be grown by direct sowing and transplanting. Direct sowing avoids transplant shock, while direct sowing is simplest where the season is long enough.
Spacing and Planting Depth
Give Fennel room to mature. The figures below come from verified extension and seed-supplier data for typical varieties.
| Spacing in row | 6 inches |
|---|---|
| Row spacing | 18 inches |
| Plants per sq ft | 1.33 |
| Planting depth | 0.25 inches |
| Sun requirement | Full sun |
Days to Maturity
Fennel reaches maturity in 65–90 days from sowing.
Fennel is ready to harvest after about 78 days. Harvest before summer heat or, for fall crops, before a hard freeze, to keep quality high.
Conditions and Care
As a cool-season herb, Fennel does its best growing in the cooler weather of spring and fall and tends to bolt or turn bitter in summer heat. It is half-hardy — it withstands light frost but should be protected from a hard freeze.
Fennel needs full sun — give it at least six hours of direct light a day for the best growth and flavor. Sow seed about 0.25 inches deep — small seed is sown shallow and barely covered, then keep the soil evenly moist until seedlings establish.
Fennel belongs to the Apiaceae family; rotating where you grow members of this family each year helps limit the build-up of soil-borne pests and disease. Fennel is generally grown as a single planting each season rather than succession sown.
Companion Plants
Pairing Fennel with the right neighbors can improve growth and deter pests; a few combinations are best avoided.
Keep away from: Tomato, Green Beans (Bush), Cilantro
Growing Notes
Allelopathic — plant away from most vegetables. Herb fennel; see fennel-bulb for Florence bulbing fennel.