Nitrogen. Collards need it in abundance. I'm just growing it for the first year, and that's what everyone is telling me. Your compost ought to have that, but you might want to add a side dressing.

Awesome - thanks! That's a great tip. I'll add something to them this week and see if that helps.

A cheap and easy source of nitrogen is lawn fertilizer. If you have any of that around, especially extended-release, sprinkle a little around the plants.

Collards are not overly choosy, BUT they do not tolerate crowding, they need to be at least 18 inches. If you direct showed in August and they are 15 inches, they are pretty much on schedule. Sown late July, Transplanted first of September. For those of you might worry about the color, those are Yellow Cabbage Collards.

Great to know! Mine are a little close as I was using the square foot method. They're about 12 inches apart (one per square). Are there any good organic nitrogen rich supplements? I've heard coffee grounds - any feedback on that?

https://www.uvm.edu/vtvegandberry/factsheets/organicN.html

Coffee grounds have low C/N, but I wouldn't use them unless they are composted. The nitrogen in them is not "available" to plants. Uncomposted coffee grounds are NOT a nitrogen fertilizer. In fact, if you dig them in soil, the microbes will use up nitrogen as they digest the grounds.

True. I am not organic so I am not up on the latest. However as an old grower, Chicken manure, Fish meal or fish emulsion, blood meal, cotton seed meal are old time N sources.