GMSgrowsanswered grow question 2 years ago Your ppm should be at the 400ppm 0.8ec to 450ppm 0.9ec at this stage in their growth. 5.8 ph through veg, check often and 6.2 and 6.3 for flowering time...Most autos you stop increasing their food when you reach 600 to 650 ppm. only give more if they really need it and keep your water as cool as you can...