catch crop

from the GNU version of the Collaborative International Dictionary of English.

• Any crop grown between the rows of another crop or intermediate between two crops in ordinary rotation in point of time.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a crop that grows quickly (e.g. lettuce) and can be planted between two regular crops grown in successive seasons or between two rows of crops in the same season