Cilantro (Corindrum sativum) leaves bring their distinctive taste to Latin American and Southeast Asian dishes. Cilantro is a cool-season annual herb that will bolt, or form a flower stalk, quickly in warm weather, if it becomes too dry or if the roots are disturbed. When it bolts, the leaves can no longer be harvested. The flower stalk produces a cluster of white flowers that attracts bees, butterflies and beneficial insects, then edible seeds, known as coriander.
Slow Bolt Varieties
Some cilantro varieties have been bred to not bolt as quickly. These varieties include "Calypso," "Slow Bolt," "Janatar" and "Leisure." Regular varieties bolt 45 to 52 days after planting. Slow-bolting varieties bolt in 60 to 75 days, so you may get one or two more cuttings from slow-bolting varieties. When stressed, regular varieties can bolt when they are only 3 or 4 inches tall, while slow-bolt varieties may be able to resist stress long enough to provide a reasonable harvest.
Cilantro is best if it is sown directly in the garden because it will bolt more quickly if transplanted. Sow the seeds about 2 inches apart. Close planting seems to delay bolting. The leaves can be cut up to four times from a single plant. Even slow-bolting varieties bolt quickly if you allow the soil to become too dry, so keep the cilantro plants well watered. For a continuous crop, sow seeds every two weeks.
Cilantro leaves can be cut when they are 4 to 6 inches tall. Either remove the outer leaves of the rosette or gather all the leaves together and cut about 2 inches above the ground, leaving the smallest center leaves on the plant. Any leaves you don't use right away can be frozen in a zip-top plastic bag. Cut the leaves each week to delay bolting.
Bolting allows the plant to produce seeds -- known as coriander. The seeds taste different than cilantro, but are used in many dishes. If you want to harvest coriander seeds, thin the plants when the seed stalks form so they are 8 to 10 inches apart and allow the seeds to ripen. When they start to turn brown, cut the seed heads and put them in a paper bag. Hang the bag in a dry, protected place until the seeds drop to the bottom.
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