This seems like a common problem, but I wanted to check with this forum.

I started many seedlings in my Gardeners Supply AP40 seed starter. I transplanted them outside about 1.5 weeks ago. They were doing ok indoors, but had some slight yellowing and white around the leaves. I moved the grow light closer and they responded nicely.

Ever since I moved them outside, they basically have not grown a bit. I added some neptune seaweed fertilizer and a few days later they got brown and sick looking. I mixed it correctly, but perhaps acted too quickly. I posted pictures. Thoughts would be appreciated. I don't want to wait for months for them to bounce back when I can replace them with transplants from the nursery.
Thx.