I am having very high success rates with germination but most of my seedlings have a hard time shedding the shell. A few of them recently grew to an inch long before losing it (with a little help from me), and they had the first set of true leaves bulging out. The cotyledons on these plants look okay but the tips are somewhat yellow and brown. Is this a problem? Should I be pulling the shells off earlier? These are from seeds started in paper towels and transplanted to rockwool cubes. The first pic shows a plant on the left that kept the shell on till the leaves were bulging, seems okay now. The plant on the right has the yellow tips and now appears stunted in growth... will she make it? The second pic shows 2 brand new seedlings. The pic sucks but if you look close the plant on the left has the same issue, brown tips on the cotyledon. The plant on the right still has the shell attached. Thanks!
Just keep in mind that the shell stays on longer than desired more often in rockwool than it does in soil. My guess is that it is the reduced friction due to the fact that the rockwool hole is predrilled wheras coming through soil the shell comes in contact with more foreign objects. Evntually, all shells will fall off, but if you are careful sometimes it doesn't hurt to help nature a little bit. They (the pics) look fine to me. Are you sure you aren't just seeing the remanence of the shell. Sometimes there is an inner membrane that can stick to the cotelydons. This is perfectly normal. Good luck.
Thanks for the tips. That is a good theory, makes perfect sense to me. Also explains why I have had quite a few more shells stick than I hear reported around here. The yellow color was what bothered me the most. I physically removed the shell only to find a day later that the inner lining was still attached. Once I peeled that off, the leaves spread open and were already yellow on the tips. Seem to be growing better now, but much slower. Both of the seedlings in the first pic are the same age... Thanks again!