cannabis on rockwool

The pH of the nutrient solution should be checked regularly with a pH meter. pH too high: lower it with Nitric acid (during the growth period) Phosphoric acid (during the flowering period) pH too low: increase it with an alkaline solution (during the whole period) Take care with these acids because they are corrosive for your big bud feminized. The pH of a nutrient solution for growing your "favourite plant" should be between 5 and 7. Because rockwool is made from rock and rocks can be very alkaline, rockwool can also be very alkaline itself. This results in an immediate rise of the pH value of the nutrient solution as soon as it comes in contact with the rockwool.