Soil Science

Soil ScienceAt first glance, it would be easy to say compost is compost. Whether the compost is being shoveled from a bag and raked into a garden or dumped by truck and tilled into a farm, the dark, rich soil looks like dark, rich soil. After all, when you walk through the composting company Brooks Contractor, there are mounds of what looks like black dirt everywhere.

It turns out there are different mixes of compost. There is compost for organic farms. There is compost for athletic fields and golf courses. There is agricultural-grade compost. There is also regular compost, which homeowners buy for their gardens. If you look closely and stick your hand in the dirt, it’s easy to see and feel that not all compost is the same.

As Amy Brooks of Brooks Contractor tells me, “Any grade of compost is good for the soil because of its nutrients and it helps retain water. But depending on the character of your soil and what you need the compost to do, there are different grades of compost to meet your requirements.”

Part of the difference is due to how well the compost is sifted to remove clay and larger objects. 

Soil SciencePart of the difference also is based on what the compost is mixed with.

Brooks Contracting calls its basic compost BR-1. It is a mix of food waste, eggshells, leaves, clean wood waste, animal bedding and other feedstocks. It does everything compost needs to do, plus the eggshells provide a natural source of slow release lime for our acidic NC soils.

BR-2 is a sandy topsoil blend that takes out the clay. It would fit with golf courses and athletic fields. Mix this compost blend into the existing soil or use it as a planting soil where irrigation is available.

BR-4 is what the company calls landscaper’s topsoil. It’s their most popular blend and what is sent out to garden centers. It’s a 50/50 mix of compost and topsoil that works for homeowners, who have planters, lawns and raised bed gardens. Of course, any compost blend would work depending on the soil where you want to plant a garden. You’ll need to ask questions and do a little research.

The company also says it can make customized compost blends, depending on a person’s needs and what soil tests show is required.

- Frank Graff

Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!


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