Im always having issues getting feeding schedual right when starting off seedlings, i cannot tell if im over feeding and it's burn or im under feeding and its deficiencies but i always have the same issues starting off with yellowing and spots. Once they are bigger i seem to do fine throughout the rest of the grow. Pics below show what im currently dealing with, 2 blue dream and a strawberry blue, they are about 2 weeks old from sprouting . The 2 BD on the left seem to be hanging in there ok, but the far right SB has all the sudden started rapidly spotting and yellowing, i am using RO water with CaliMagic and DynaGro-grow at the moment, will be adding Humbolts Seceret GoldenTree once they are bigger and stable. Can anyone reffer me to a nutrient application guide? One that will help me to properly regulate my hydroponic nutrient schedule? Most i find just explain the basics of nuits like, manufacturers feeding chart, NPK, macro/micro ,PH etc. Rather than the application mixing, monitoring, adjustment, etc. Once agin im only having problems with seedlings and the first couple weeks of veg
They look oxygen deprived. Is that rockwool that they are in? And is it sitting in water? If so you are drowning the plants. As far as your nutes go, just pick a balanced complete nutrient and forget all additives and boosters and follow this link http://forum.grasscity.com/hydroponic-growing/1198022-how-determine-what-your-plants-preferred-nutrient-strength.html .
Like Gold mentioned, rockwool will hold enough nutrient solution for days, for plants that size. Maybe soak them once as soon as lights go on, but not after that. I also second what Gold said, and recommend moving toward a complete nutrient, and quit messing with additives and such. What's your pH? Are you preparing your rockwool ahead of time? (This is important, as it will cause your pH to go up up up, if not) Note, no cannabis seedling will need ANY nutrients from you until the cotyledons start turning yellow. That's your signal to start feeding them.