What is topsoil and what is it made of?
CARVER, Minn. — Soon homeowners and gardeners will be getting their hands dirty. Growing flowers, plants, and grass requires a dark and seemingly plentiful ingredient.
We wanted to know: What is topsoil and what is it made of? Good Question.
It's a dirty job and that's just the way Brandon Leistiko likes it.
As clouds of dirt swirled in the wind around his property, crew members assembled his top concoction: a topsoil blend. Piles of topsoil and compost are mixed together in a screener. The heavy machinery only allows particles smaller than three-eighths an inch to fall through, separating rocks, sticks and other objects that are too big for the fine topsoil blend.
"If we were making a garden blend or something like that, we would either add a mushroom compost, organic manure, or more yard waste compost," he said.
He owns Minnesota Topsoil in Carver where the nutrient-rich black dirt is created.
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"It's kind of funny to say that you make dirt, but it's exactly what we do here," he said.
Before we break down his manufactured blend — which is all-natural — let's explain nature's topsoil. Like the name suggests, topsoil is the top layer of the earth's crust.
It's a mixture of silt, sand, clay and mainly time. Those several inches of topsoil below a layer of grass in a field took centuries upon centuries to create. Organic material from decaying plants and animals, as well as water and air help complete the equation for topsoil to form.
Leistiko's topsoil blend is natural but homemade.
"We don't dig it out of the ground. We take all of our feed stocks that are here and we mix and blend them, process them and engineer our own soils," he said, adding that they use organics, peat, and some sand.
Where does the topsoil sold in bags are hardware stores come from?
"I would say it's not native to Minnesota depending on what you're getting. If you're getting the cheapest grade material, more than likely it came from out of state," he said. "(The manufacturers are) composting material down, they're adding a source of nutrients mixed with wood fines mixed with another component to create a mix of black dirt blend."
For Leistiko's topsoil blend is 70% topsoil and 30% compost. The compost is made of leftovers from yard waste like leaves, branches and weeds. His crew then carefully accelerates the decomposition by checking the pile's temperature, then "turning" it every 4-6 weeks. In essence, they move the compost pile and move it 100 feet into a different pile. They'll repeat this process for 18 months before it turns into fine, dark dirt. It can be sold as is or mixed into their topsoil.
"It's kind of what we've come down to the science part of it as far as how we transition it from a leaf particle and 18 months later, I can sell it back to you as a dirt particle," he said.
Leistiko suggests people test the soil in the yard or garden to know its composition. That will help with purchasing the right type of topsoil for your project.
