well it depends, i started off feeding nutes after the seed leaves turned yellow, and i started with 1/4 strength, and worked my way up to full strength. how ever some strains are light feeders and some are heavy feeders, you just have to work your way up to full strength and keep and eye on the plants, if the very tippy tip of the leaves turn yellow/orange and look burnt and your feeding full strength nutes awesome, for that strain you seem to have found its sweet spot. now if you work your way up to full strength and more then the tips of the leaves burn the nutes are too strong and you need to back off on the strength untill only the tippy tips are burnt no more then the tips,
i hope you understand this, its early and im super tired still.,.. but basicaly start off 1/4 strength and work up to full strength and keep an eye on the plants they will tell you if thats too much food or not enough food for them... like i said some strains are heavy feeders and some are light feeders, White Widow for example tends to be a light feeder, infact alot of the white strains tend to be light feeders, where as something like Skunk #1 or this strain my buddy has called Sticky, wish i knew what breeder he got the sticky seeds from, zomg amazing buds,,, anywho back on track so this sticky plant is a stupidly heavy feeder, my buddy when he started growing Sticky he searched for that feeding sweet spot where the plants eat as much as they can without more then the tips of the leaves burning, well he never found it, gave up infact lol, after pumping the nutes up to 3x full strength and still NOT burning the tips he gave up on finding out how much he can push into the plant without burnt tips, but 3 times full strength thats alot of nutes and he didnt wanna use more nutes so stopped at 3x strengthm but if you ask me im sure it could tolerate 4x strength but then again that is alot of nutes, and quite expensive feedings.
so pretty much we cant tell you how much your plants will tolerate thats something you will have to experiment with on your own, just keep track of how much you feed and make adjustments accordingly based on your plants reactions to the specific strength of nutes used to feed.,