My tomatos didnt wanna get going till i fixed my PH, man it was like 7.0 when i started cause of low nutes. Unfortunatley i didnt have time to go to the hydro store so i got some PH down for fishtanks and it worked great. Once every couple of days i throw some in, i try and keep it around 6.0-6.2 as i hear thats a good range to not worry about lockout, things have since gone thru the roof Good luck with those man