Brassica oleracea var. viridis
Collards are yummy when they’re harvested young, dark green and less than 10 inches. The older the leaves are the tougher they’ll be.
• Like kale, you should harvest the individual leaves, one by one, and leave the central stalk.
• While you harvest, remove any yellowing or discolored leaves so that new, healthier leaves will be encouraged to grow.