Calculating Compost Bulk Density
Materials Needed: 1. Compost pile |
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Procedure:
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With a 1-gallon measuring container, fill 5-gallon bucket with 5 gallons of water as the brim of a "5 gallon bucket" is not necessarily 5 gallons. Mark this line on at least 3 places on the inside of the bucket with a permanent pen.
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a) Buckets with straight sides (ie diameter at the top of the bucket is the same as the diameter at the bottom): measure height from bottom of inside of bucket to the 5 gallon line, divide this number by 3, and mark the bucket as above at 1 times and 2 times this number. For example, if the 5-gallon mark is 13 inches, dividing by 3 will get 4.33 inches, so mark that bucket at 4.33 inches and 8.67 inches.
b) If you cannot obtain a bucket with straight sides: find the two intermediate lines by measuring first 1 2/3 gallons (=1.67 gal or 6.31 liters) then 3 1/3 gallons (=3.33 gallons or 12.62 liters) of water into the bucket and marking where the water line is at both volumes with a pencil when wet, then a permanent pen when dry. -
Compost used should be representative of the pile. Take handful samples (not large shovel full samples) from several locations in the pile. Dig into pile a couple of feet, do not take from dried-out outer layer of pile.
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Fill bucket to the 1/3 line with compost. Drop bucket squarely from approximately 1 foot high to the ground (hard surface) 10 times.
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Fill bucket to the 2/3 line. Drop bucket squarely from approximately 1 foot high to the ground 10 times.
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Fill bucket to the 3/3 (5 gallon) line. Drop bucket squarely from approximately 1 foot high to the ground 10 times.
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Fill bucket again to the 3/3 (5 gallon) line and weigh in pounds.
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Multiply weight of material in pounds (excluding bucket weight) by 40.
This is your bulk density, in pounds per cubic yard.