I'm working with a total of about 25 square feet for my raised garden beds, and I'm trying to keep costs down. Can I just use regular dirt from my yard at the bottom, then lay down some cardboard to block grass growth, and finally add soil on top? I'd like to know if the cardboard is necessary since I only have about 6 square feet of soil available. Any tips?
3 Answers
In my experience, you don't really need the cardboard. If the native soil isn't too heavy on the clay side, it should work out just fine. Just make sure to monitor for any grass that might sneak in!
How tall are your raised beds? I've had good luck putting native soil directly on top of grass without any barriers like cardboard, even in a 2-foot bed. Just make sure your local soil is suitable for growing veggies!
Using native soil is totally fine if it's good for growing. But if your yard soil is clay, it could mess with drainage when mixed with your raised beds. Also, you might not need the cardboard—many people have successfully placed soil directly onto grass without it. Just keep an eye on the grass to ensure it doesn’t grow back!

Yeah, I used native soil last year in my 2-foot raised bed without any cardboard and had no grass issues. Just keep the layers well-mixed!