I'm about to install four 4x8 raised beds that are only about 1 foot tall, since I've moved to a new place with poor soil quality. I've always used a garden plot, but now I'm switching to raised beds. Do I need to kill any existing vegetation under the beds first, or can I just fill them with soil right away?
3 Answers
Twelve inches of soil should take care of most weeds and grass underneath, but adding a layer of cardboard is still a solid move. If there are any aggressive weeds in your area, it's best to dig those out first to make sure they don't pop back up.
I recommend placing down some cardboard before adding the soil. It helps suppress any existing vegetation while breaking down over time. It can be done all at once or let the cardboard settle for a few weeks if you prefer.
In my experience, I removed the sod and ended up pitchforking down a good amount of soil. I found a lot of rocks, so I filled the beds with some good topsoil, compost, and peat afterward. If I do more beds, I might try a semi-hugelkultur approach, layering twigs and leaves at the bottom to improve drainage. This was more about removing the rocks than dealing with vegetation, though.
Thanks for the tips! I'll definitely check for any invasive ones before I start.