I agree with you on a number of factors there. I always tell people not to change more than 1 variable at a time. That way you know what to blame it on. If you've adjusted PH, weakened the nutrient solution, changed something about the lights and transplanted all at the same time, you really can't tell what happened. If I were you next time this happens I'd really just adjust one thing and wait a couple days to see if the problems gets worse or better. These plants are resilient (especially in the veg stage) and they are very hard to kill. In coco you can change things in an instant so even if they are on their last limb (which yours are far far away from) you can save them. It's worth the knowledge and experience by letting them possibly get worse just to be able to pinpoint the problem and learn from it. We can help you but each one of us experienced growers might come up with a different answer for the problem. Derby for instance might be right this time about the overfeeding and we might be following a different thread and say the same things in the other (assuming they have a plant that is doing the same thing as your GSC) and I might be right about the transplant stress in that thread. Either way if you just change things one at a time and figure out what it is for sure, that knowledge is invaluable for the rest of your growing life.
With all that being said I will try and narrow it down a bit for you.
1. If the nutrients were too strong you would see the tips of the leaves burning. If the plant is really dark green it more than likely means you might be a little heavy on Nitrogen, however my plants are really dark green until flower most of the time.
@Mr. Magoo uses Doc's soil kit which is almost a perfect kit for growing in soil and you should see how dark green his leaves get. Hit POTM submission this month is a perfect example. Also I use my own schedule as a guide but there have been plenty of times I've measured the EC/PPM and it was hundreds over and I just said screw it and dumped it in and never saw any sort of overfed problems. Once again I am not saying that isn't the problem here but for these reasons I really don't think it's that in my opinion. Key word, opinion.
2. PH is an interesting subject but I don't PH anything at all. 5.8-6.2 is a very detailed place to be in terms of PH. You really could be anywhere between 5.5-6.5 and the plants would be fine. I did a write up in my thread recently on PH and if you haven't seen it take a look. It is just a theory after all but I think it makes sense on how to use PH with coco.
3.
@Dutchman1990 I believe had sort of droopy plants in relation to changing lights and light intensity during the grow. I think 3 out of 4 of his plants recovered when he raised the lights and one just was droopy the whole way but ended up doing fine. As stated by someone prior, different lights can also give off different heat but I think the droopyness is more so from the intensity and not the heat, especially if your temp and RH seem to be stable and not all over the place.
4. Lastly, I believe you mentioned not being able to get the Great White Mycorrhizae but ever since I sprinkled this stuff in the holes before transplant, I haven't had a single issue with transplant stress. The stuff is like steroids for your roots and they just immediately take off. It's spendy but the same jar has lasted me forever and I only use it during transplant. Liquid stuff (like rapidstart) is great to put in with your feeds but the dry powder really gets direct contact with the roots when you sprinkle it in the transplant hole.
