GardenNotes #233
Calculating Fertilizer Application Rates
Outline: Steps to calculating fertilizer application rates
Fertilizer application rate table
Steps to Calculating Fertilizer Application Rate
Example is for a 40-foot by 100-foot lawn area, using a 20-10-0 fertilizer
1. Calculating size of area to be fertilized
| __ ft. long | X | __ ft. wide | = | ____ square feet |
| Example: | ||||
| 40 feet | X | 100 feet | = | 4000 square feet |
2. Calculating fertilizer application rate
| __ lb. nutrient per ____ sq. ft. / __ % nutrient in fertilizer | = | __ lb. fertilizer / ____ sq. ft. |
| Example: | ||
| 1 lb. nutrient per 1000 sq. ft. / 20 % nutrient in fertilizer | = | 5 lb. fertilizer / 1000 sq. ft. |
| (.20) |
3. Calculating pounds of fertilizer to apply
| lawn or garden area X application rate | = | pound of fertilizer per garden or lawn |
| ____ sq. ft. / garden or lawn X ___ pounds fertilizer / ___ sq. ft. | = | __ pounds fertilizer / garden or lawn |
| Example: | ||
| 4000 sq. ft. / lawn X 5 pounds fertilizer / 1000 sq. ft. | = | 20 pounds fertilizer / lawn |
Additional Information – CMG GardenNotes on Soils, Fertilizers and Soil Amendments:
#211 The Living Soil
#212 Earthworms
#213 Managing Soil Tilth
#214 Estimating Soil Texture
#215 Soil Compaction
#216 Mulching with Wood/Bark Chips, Grass Clippings and Rock
#217 Soil Drainage
#221 Soil Tests
#222 Soil pH
#223 Iron Chlorosis
#224 Saline Soils
#231 Plant Nutrition
#232 Understanding Fertilizers
#233 Calculating Fertilizer Rates
#234 Organic Fertilizers
#241 Soil Amendments
#242 Using Manure
#243 Using Compost
#244 Cover Crops and Green Manure Crops
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Authors: David Whiting, Adrian Card and Carl Wilson: Colorado State University Extension.
o Colorado Master Gardener GardenNotes are available on-line at www.cmg.colostate.edu.
o Colorado Master Gardener training is made possible, in part, by a grant from the Colorado Garden Show, Inc.
o Colorado State University, U.S. Department of Agriculture and Colorado counties cooperating.
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o No endorsement of products mentioned is intended nor is criticism implied of products not mentioned.
o Copyright © 2002-2006. Colorado State University Extension. All Rights Reserved. CMG GardenNotes may be reproduced, without change or additions, for non-profit educational use. Revised December 2006