need alot more info bro. Using tap water? RO? What light? What kind of nutes? Whats the environments temp like?
IMO using ro eliminates potential problems. If you are using ro, check the filter, test the water.
Tap water with GH nutrient at 6.5ph and 800ppm. Plant at 5weeks old. Using promix hp soilles nothing added. Temp 28C with 45% humidity. Water every 2,3days or more till soil dry. Using hps 1000w lamp . please help