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FERTILIZER ANALYSIS AND RATIO
FERTILIZER ANALYSIS

analysis - sequence of 3 numbers on the fertilizer label that gives the percent composition
                of N-P205-K20 in a fertilizer; required by law to be on the label of every fertilizer sold. 

Example: 8-8-8 means the fertilizer contains:
8% N 
8% P20
8% K2
24% total nutrient content 

          Buy fertilizers by price per pound of fertilizer, not price per bag.
100 lb. of 8-8-8 @ $4.99
100 lb. @ 24% = 24 lb. of nutrients
@ $4.99 = 20.8 cents per lb
100 lb. of 13-13-13 @ $5.99
100 lb @ 39% = 39 lb. of nutrients
@ $5.99 = 15.3 cents per lb.

 
 

FERTILIZER RATIO

ratio - the relative proportion of N to P205 to K20 in a fertilizer.
 
Analysis 
8-8-8
20-20-20
10-20-10 
18-6-12
Ratio 
1-1-1
1-1-1
1-2-1 
3-1-2

 
 

USING FERTILIZER RATIOS TO MANIPULATE PLANT GROWTH

a) to favor vegetative growth

  • use a high N, low P and K fertilizer 
  • for example, use a 2-1-1 or 3-1-1 ratio fertilizer (higher 1st number) 
b) to favor flowering, root and underground storage organ growth
  • use a low N, high P and/or K fertilizer 
  • for example, use a 1-2-2 or 1-3-2 ratio fertilizer (higher 2nd and/or 3rd number)