Cabbage, Eggplant, and Cauliflower with white-ish dry spots

Question

I've got eggplant, cabbage and cauliflower seedlings growing inside in peat moss with some all-around fertilizer (24-8-6). However, the edges of their leaves are drying and curling up, and some of them have dry, beige spots in the middle. I thought it might have been a calcium deficiency, so I boiled some eggshells and added them to each of them. I've attached an image of the cabbage seedlings. It's been 2 days now, and their condition is deteriorating. First of all, is this indeed a calcium deficiency? And if so, what should I do to rapidly restore the leaves?

Answer 1

It looks to me, they are over fertilized. Especially if you add 24-8-6. Diluted 1-2-1 should suffice for those growing roots.

Answer 2

Peat moss is acidic and calcium is usually alkaline; so, calcium-deficiency is a definite possibility. I can't say if that's what it looks like, right now, though. However, this Wikipedia article says lettuce and cabbage with calcium deficiency may experience burned edges of their leaves (and that's kind of what's going on here).

It's possible that the calcium didn't help at first because there wasn't enough nitrogen to balance the calcium until you fertilized again (you need both balanced). Pure peat moss, as I understand it, doesn't have many nutrients at all.

If you're fertilizing with 24-8-16 All-purpose Miracle Gro, you should know that it doesn't contain any calcium, nor any magnesium. So, you might need magnesium, too, in time. I doubt peat moss has much magnesium. Epsom salt is an easy source of it.

You should also know that it can be easy to over-fertilize with 24-8-16 All-purpose Miracle Gro (so be careful).