Plant your young fennel plants in well-drained warm soils. Manure, compost or other nutritious organics should be added to the soil to help retain moisture and encourage the leaf base to swell. Avoid stony or heavy clay soils so the leaf base can swell with no obstructions. Plant them 9 to 12 in. apart in rows 18 in. apart.
Fennel thrives when it has plenty of water. Dry weather or dry conditions will keep its stems from becoming bulbous.The leaf base is blanched (turned white) toward the end of the season by drawing up soil around the leaf base when they reach golf-ball size.Hoe around the plants to keep the weeds to a minimum.
After four weeks from “hilling up” the leaf base, the fennel should be ready to harvest. The bulbs will be tennis-ball size or slightly larger. Harvest the entire leaf base by cutting under it with a sharp knife.
The bulb of fennel can be sliced and used raw in salads or they can be cooked whole by boiling. Fennel’s leaves are also flavorful and can be an herb substitute for common fennel.