Related to endive, escarole, and radicchio, chicory is a warm season vegetable. The names chicory and endive are sometimes used interchangeably, although this is not technically correct. Chicory has oblong, basal foliage, which forms a loose head of dark green leaves that can be used in salads. The roots of 'Magdeburg' chicory are ground and used as a coffee substitute or additive. What is known as French or Belgian endive is actually a chicory, called witloof chicory, which is forced and blanched in the dark to produce tubular heads of leaves, usually but not always indoors in the winter.
Chicory seeds are planted outdoors after all danger of frost has passed, 1/2 inch deep and 4 inches apart in rows 18 inches apart. Thin plants to 12 inches as they grow. Chicory grown for greens needs average soil; chicory grown for root requires a soil that is loose, rich, and moist. Fertilize at planting time and again in 2 months.
To harvest chicory for leaves, pick them at any time until frost, after that they become too bitter. Plants are hardy to -40 degrees F and can be left in the ground all winter, and new growth harvested in spring. If allowed to grow as a perennial, chicory produces blue flowers in summer. For roots, harvest after the first fall frost.
To grow French or Belgian endive, grow witloof chicory from early summer to fall. Then, after cutting back the tops and digging up the plant, set the roots in moist soil in a warm cellar and cover with a 6 inch layer of moist sand. New leaves will grow in the sand and produce tight, blanched heads.
In mild-winter areas, the same results can be achieved in the home garden. Sow seeds in early summer, not before, because a plant that goes to seed is useless for forcing. Thin seedlings to 4 to 6 inches apart. When plants are fully grown and the first frost hits, cut off the tops two inches above the crown to prevent injury to the crown buds, then cover plants with 6 to 8 inches of soil. In late December start harvesting in the first few feet of the row by removing the soil to expose the white shoots. After cutting the shoots, scrape the soil back over the roots in a mound to force a second crop. By driving a stake, you can mark how much row you have harvested. The harvest can go on through the winter and early spring.
The leaves of chicory are used alone or mixed with other greens in salads. They have a slightly bitter flavor. Chicory roots used for coffee should be dried and ground immediately after harvest. Add an ounce of ground chicory to a cup of ground coffee before brewing for a coffee reminiscent of that served on the Left Bank of Paris or in New Orleans. French or Belgian endive (the forced greens are called chicons) is used fresh in salads; a winter favorite is a combination of chicons and beets. Endive can also be steamed until tender (about 10 minutes) and topped with a seafood creole.