When to start feeding seedlings?

Hey RIU I was just wondering right now, I have some new clones that I recently put into rockwool, I now have a few seeds to pop and was wondering will they be able to catch up to the new clones PPM? I am feeding 600PPM for this initial phase and they are looking good, but im assuming thats too high for a little seedling?

start feeding 6 days after planting with half strength mixtures is something i was told by someone i know who grows the best shit i've ever smoked i've always taken his advice and never had a problem but maybe someone with a little more experience will come and shed some more light on your question

i start seedlings with 300-400PPM solution and never had an issue! actually now i prefer to use the RapidRooter plugs from GH that have already Micro Nutes for the seed to germinate well. Organic and works well with hydro.

Does it come to a point (like week wise) where they can handle a slightly higher PPM, I would love to run new clones in same tray as those week into veg, haha elsewise the 3 seedlings will go DWC!