1. calculate the molecular weight (mw) of the molecule:
   • Example fertilizer: Nitrate (NO₃)
     • 1 Nitrogen = 1 x 14 = 14
     • 3 Oxygen = 3 x 16 = 48
     • 14 + 48 = 62
2. calculate the % element in the molecule:
   • Example: NO₃ = 62
     • N / NO₃ = 14 /62 = 22.5%
     • => 22.5% N in NO₃
3. calculate weight of fertilizer needed:
   • Example: Nitrogen target of 100 lb/acre
     • 100 lb/acre = 0.25 lbs per 100 sq ft
     • veggie bed = 150 sq ft
     • => N target = 0.25 x (100 / 150) = 0.375 lbs N
     • => 0.375 / 22.5% = 1.67 lbs NO₃

=> 1.67 lbs NO3 needed for amending 150 square foot bed to reach 100 lb/acre target