ok i'm new to coco and my first thought is that seedlings, like in soil i don't feed till a nice set or two of "real" leaves form. but since coco has no real nutrient value would the seedlings need nutes as soon as they emerge from the soil? and at what strength. most of the crosses are bubba sour diesel and purple kush but also some trinity x startrain and a c99 x startrain are there also. i guess at what size and at what strength are the questions i am looking for. heres a picture so you can see where i am at.
After damping off quite a few seedlings while trying to learn coco, i now like to bottom feed my babies until they're big enough to take a good soaking. I start off in small yogurt cups bottom fed with 1/4 strength nutes ( i'm currently using Cutting Edge Solutions) until the roots hit the bottom. Then i transplant them into bigger cups and hit them with 1/2 strength nutes (again until the roots hit the bottom). Then they're ready to be transplanted and top fed at full strength.
Good luck bro.
I wouldn't feed them anything at this stage. I'd also add some perlite to that coco to aerate it a bit more. Let them get to about 1-2 weeks old then feed a diluted veg nutrient. The little seedlings wont be able to handle nutrients at the stage they are at. Could look at a plant starter solution though which is designed to promote new and additional feeder roots, but its mainly used in conjunction with transplanting.