Usually, the microgreens produce only one set of leaves called seed leaves which are harvested only once and do not regrow as after harvesting the seed leaves, there is nothing left for them to collect the sunshine & prepare their food. But, some microgreen shoots and grasses like peas, lentils & wheatgrass are exceptions. They produce more than one set of leaves; you can harvest them 2-3 times by cutting them from above by leaving one set of leaves to help them regrow.