|Collards are one of those vegetables that tend to be regional though they really don’t have to be. In the south they are grown everywhere but when you leave the southeast they are difficult to find and even asking for them will result in more than a few strange looks.
They are in the same family with broccoli, kale, and cabbage. In fact they are similar to cabbage that grows in leaves instead of heads.
You can start collards from seed in a standard soilless potting mix indoors about 4-6 weeks before you want to transplant them outdoors. Water the mixture before seeding, then when dry after germination.
Collards are best when they have been through a frost or two, which is why they are often planted in the fall, though spring is also acceptable. The cool temperature tends to make the leaves sweeter and in warmer zones collards are often harvested all winter long. For that reason, plant transplants outdoors 3 to 4 weeks before the last frost date in your area (spring) and about 6-8 weeks before the first frost (fall).
A well-drained soil with a pH of 6.5-6.8 is important to ward off a disease known as clubroot.
Harvest the outer leaves of the collard first when they are at least 10” long.