Fertilizer Labels and Calculations

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Fertilizer Labels and Calculations
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We will learn-

• How to read labels
• How to calculate amounts of fertilizer needed for
  an area

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Fertilizer labels

• Some information is required by law to be on the
  fertilizer bags
• Net Weight
• Brand and grade of fertilizer
• Guaranteed analysis of each nutrient in
  fertilizer
• Name and address of manufacturer

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Other valuable information

• Some manufacturers add the following on the bag
  as well
• of water insoluble nitrogen
• Potential acidity
• Salt index
• Source of carrier
• of minor elements
• Calculation rates
• How to calibrate spreaders

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How much fertilizer?

• We have a grass lawn that needs to be fertilized
  and Jake has found a bag of 16-8-8 in our garage.
  If we need to put 1 pound of nitrogen per 1,000
  sq ft of our 16,725 sq ft lawn, how much
  fertilizer do we need to apply?

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How do we figure this problem out?

• Total Fertilizer Needed

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How much Phosphorus has been applied?

• Assume we are applying it at the recommended N
  amount
• P Recommend N rate X of P in of N in
  fertilizer fertilizer
• Can figure K amount the same way!

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How much to feed plants

• Vegetables
• For a 60ft row
• 2 ¾ cups to 4 ½ cups
• ½ early in season
• Repeat 4-6wks later
• Bulbs
• Amount per plant
• 1tbsp 2 ½ tbsp
• When leaves emerge

• Roses
• Per plant
• 4 ½ tbsp ½ cup
• 1/3 at new growth
• After every bloom
• Deciduous tree/shrub
• 100 ft2 under leaf canopy
• 4 ½ tbsp ½ cup
• 1/3 when new growth
• Repeat twice at 6-week intervals

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More plants

• Lawns
• Per 1,000 sq ft
• 1 pound/ 1,000 sq ft
• Feed 3 times per year
• Evergreen tree/shrub and rhododendrons
• Per 10 sq ft of canopy
• 3 tbsp 1/3 cup
• Feed half at bud swell
• Repeat after deadheading

• Flowering Perennials
• Per plant
• ¾ cup 2 cups
• Half at new growth, then in 6 wks
• Flowering Annuals
• Per 100 sq ft
• 1 ½ cups 2 2/3 cups
• At planting, then in 6 wks