There are crabgrass species that grow in tropical, subtropical and temperate regions, and if conditions are right it can germinate throughout the growing season. They often grow abundantly in lawns that are watered lightly, underfertilized, or poorly drained. They are annual plants, and each plant is capable of production 150,000 seeds in one season, which expand outward up to 12 inches. The areas left empty by the dying crabgrass at the end of the season are especially vulnerable to new crabgrass growth the next season. Crabgrass growth can be inhibited if a herbicide is applied at the right time to interfere with a key enzyme when the seed germinates.