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?