Beginner Gardening: Phosphorus deficiency?, 1 by masciam

masciam wrote:
Two months ago I started several wave petunias by seed and after 1 month I had to travel for a couple of weeks, so my brother watered them while I was out. When I came back most of them had purplish leaves and stems and relatively small leaves. After some research I'm pretty sure it's phosphorus deficiency, because they were planted in a peat-based medium (which doesn't have much nutrients to offer to the plants) and never were fertilized.

Las week I fed them with 15-30-15 and they seem to be recovering (the new growth looks good) very slowly. All the growing guides for spreading petunias says they must be fed every week, but they still look stunted and I'm not sure if I should fertilize them again right now. I'm afraid to overfeed them!

BTW, will they ever look good again?

Thanks!