http://boards.cannabis.com/plant-pro...hy-how-do.html
Follow the directions in here EXACTLY.
Your low pH has locked out all the metals. That's why it looks like a REALLY bad Mg deficiency.
When the soil dries out from the flush and pH adjustment, get that plant into a larger pot of an unfertilized potting mix such as promix that has plenty of lime in it, and give it tap water at pH 6.7-7.0. The soil in that pot has had all the lime used up and you are now seeing what the true pH of un-buffered peat is!
stinkyattic Reviewed by stinkyattic on . Which deficiency is it??? Need Help Please!! Hey guys anyone call tell which deficiency is it? Started first with the older leaves. They're getting yellow, curved down and the veins are still very green. I managed to get the temps and humidity okay. Watering every 2 or 3 days for now on... Please help! Doesn't seem like Mg deficiency to me... Rating: 5