(Image from: https://hudsonvalleyseed.com/products/champion-collards?_pos=1&_sid=0fffffd72&_ss=r)
Growing Instructions for Champion Collards:
Start collards indoors 6 weeks before planting date. Transplant when plants are 4" high, 18" apart. Harvest larger outer leaves, leaving the smaller inner leaves to grow.
Collards prefer cooler temperatures and thus make a good spring and fall crops. They become extremely sweet after a frost, and last in the garden unprotected beyond December. For a hearty cold season supply, start indoors in early July, transplant in August and let grow until first frost date. In a mild fall, they will continue to grow if harvested regularly.
(from Hudson Valley Seed Company website)