Soil, Volume, and Weight for Dummies

A truckload of topsoil

It's pretty much an article of faith around the Antisocial Network conference table that if you say that a measurement – of anything – depends on an external factor, the measurement doesn't have an exact value. Say someone asks, "What's the speed of a fastball?" Obviously, the speed depends on the skill level and (to some extent) the age of the pitcher; so a blithe answer of "97 MPH" just won't cut it, especially if whoever answers the question does not introduce the answer by saying, "The speed depends on the skill level and (to some extent) the age of the pitcher"! Yet that's exactly what GardenGuides.com freelancer Lisa Larsen did when answering the question, "How Many Pounds of Topsoil in a Yard?"¹

Yup, Larsen's entire post told the world that,

"Topsoil and other loose items such as gravel, sand and rock are measured in cubic yards. A cubic yard of topsoil can weigh different amounts depending on the moisture content. Assuming the topsoil is dry, an average a cubic yard [sic] will weigh 2,250 lb."

For her five bucks (the going rate for short answers at eHow in those days), Lisa also managed to cite two references for her information, neither of which is still around today. A couple of trips to the Wayback Machine at archive.org, however, showed us that the weight of a yard of topsoil isn't necessarily 2,250 pounds. One of Larsen's cited references clearly states that the weight of a yard (27 ft³) of soil mixes can weigh "between 1,300 to 1,600 lbs"; while a second simply states Lisa's slapdash choice, 2,250 pound per cubic yard. A different site altogether is considerably more informative while being less specific:

"One cubic yard of topsoil generally weighs about one ton (2000 pounds). Topsoil's weight can vary greatly due to moisture content. In the dryness of the summer, the weight of a cubic yard of soil can drop down to around 1700 pounds, while in the spring when soil is damper, one cubic yard may weigh well over one ton."

Home Depot sells Scott's topsoil in ¾-ft³ bags with an average weight of 43 pounds. A little math suggests that the 36 bags necessary to make up a cubic yard would weigh 1,548 pounds, not 2,250. That, in our considered opinion, suggests that Larsen stopped talking too soon: a good answer, as opposed to a Dumbass of the Day answer, would have been that the weight varies widely depending on moisture content, but ranges from about 1,600 to 2,800 pounds, averaging 2,250 pounds or so.

¹ The original has been deleted by Leaf Group, but can still be accessed using the Wayback machine at archive.org. Its URL was   gardenguides.com/130878-many-pounds-topsoil-yard.html

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