Bolting is the premature production of a flowering stem (or stems) on agricultural and horticultural crops before the crop is harvested, in a natural attempt to produce seeds and hence reproduce. These flowering stems are usually vigorous extensions of existing leaf-bearing stems, and in order to produce them, a plant diverts resources away from producing the edible parts such as leaves or roots, resulting in a poor quality harvest from the grower's point of view. Plants that have produced flowering stems in this way are said to have bolted. Crops inclined to bolt include lettuce, basil, beetroot, brassicas, spinach, celery and onion.