Nutrient Lock Out PH Ranges (N) - 4.5-5.0 (P) - 6.0-8.5 (K) - 4.0-4.5, 6.0-6.5 (Mg) - 2.0-5.7 (Ca) - 2.0-5.3 (Zn) - 5.7-8.5 (Fe) - 2.0-3.5 (S) - 2.0-5.5 (Mn) - 2.0-4.5 (B) - 2.0-5.0 (Cu) - 6.5-9.0 (Mo) - 2.0-5.5