Soil for raised beds

Asked May 13, 2020, 1:15 PM EDT

Hi all, We are planning a large raised bed garden. Approximately 12 cubic yards total volume will be needed. I am trying to figure out what to fill our planters with as well as where to obtain the materials. I would like to do it organically but have found even the more basic garden mixes to be somewhat out of budget. Also I don’t like that the landscape suppliers generally don’t have a great idea of what goes into their mixes. Thus I am wondering about creating my own mix from top soil and compost - perhaps other materials as well? I would like to spend between $25-$30/cubic yard. Can you give me some tips of a percentage mix for my soil? Also what questions I should be asking when evaluating top soil and compost? Thank you.

Kent County Michigan

1 Response

Thank you for the question. A 50/50 mix of top soil and compost is a popular composition for soil in a raised garden. Getting top soil and compost can be daunting. The term "topsoil" is not well defined. Whether purchased in bags or bulk it should not be fine or powdery or appear very sandy. Small aggregates suggests a healthy top soil. It is appropriate to ask where the topsoil was obtained. Compost should have a dark appearance and have that pleasant soil smell. Composted manures can be a good source for compost. Regardless of what you end up with it would be a good idea to get a soil test (http://homesoiltest.msu.edu/). Check out the following links:
https://www.canr.msu.edu/news/starting-a-raised-bed-garden
https://ucanr.edu/sites/MarinMG/files/116762.pdf
I hope this helps,