Hi AA
What soil are you using.???
I've just changed from Mirracle grow to
John innes no 2 with a mix with
Vacumilite and
Perelite. Nutes -
epson salts (less added thans says on packed just to get them used to it.
Gave each little twig 13 litre round pots with over water trays.
What a huge difference. Looking really good.
Like you I have no idea how much to water. At the moment 1 litre between 2 pots.
Mind you I changed from envoilite 125 to 400 hps, so the soil dries out that bit quicker, but the plants are growing quicker, this could be due to the change of soil tho.
Have you got a temp gauge??