What is "catch crop"

Catch crop \Catch crop\ Any crop grown between the rows of another crop or intermediate between two crops in ordinary rotation in point of time. -- Catch"-crop`ping, n.

Radishes . . . are often grown as a catch crop with other vegetables.
--L. H. Bailey.

n. a quick-growing crop (e.g. lettuce) planted between two regular crops grown in successive seasons or between two rows of crops in the same season

In agriculture, a catch crop is a fast-growing crop that is grown between successive plantings of a main crop.

For example, radishes that mature from seed in 25–30 days can be grown between rows of most vegetables, and harvested long before the main crop matures. Or, a catch crop can be planted between the spring harvest and fall planting of some crops.

Catch cropping is a type of succession planting. It makes more efficient use of growing space.

Catch crops are also crops that are sown to prevent minerals being flushed away from the soil. By using catch crops, such as grain ( millet, ...) one can keep certain minerals not attached to the humous-clay connection (such as carbon (C) and other positively charged elements) in the soil for (many) years.