How to make topsoil
When you order topsoil, do you really know what you’re getting?
In some developed areas, most of the topsoil has been scraped away or eroded. What passes as topsoil is really subsoil – nearly dead dirt. It will not function like good soil.
The good news? You can make your own, be assured of its quality, and likely pay less than having topsoil trucked in. Here’s how:
FOR EXCAVATED SOIL: Mix the native soil with compost at a ratio of about 1 bucket or shovelful of compost to every 2 of soil. A 30 percent compost content is recommended for raised beds and containers.
FOR IN-SITU SOIL: Work 2-3 inches of compost into the top 6-8 inches of native soil.
Compost is a very “forgiving” material. It’s hard to use too much (though you shouldn’t use it instead of topsoil), and as little as 1/8 inch can be enough to give your soil a boost.
Whatever the amount, be sure to blend well so the compost is evenly distributed.
How can you tell if a soil is good or bad?
The ideal soil for growing things will be a mix of sand, clay, and organic matter. If having your soil tested, be sure the report will include these parameters.
Forging ahead without the soil test? The first part of this article describes various soil types and provides simple methods of identification.
If you need to add sand or clay in addition to compost, ask your landscape supply yard for a custom blend.
According to this article, most soil scientists agree that 50% pore space, 45% mineral matter (sand, silt, clay), and 5% organic matter make up an ideal ratio. A typical compost is 50%-60% organic matter (dry weight).