Hi Adrianna,

I wasn’t able to find any university research on this issue. It wouldn’t hurt to do this if you want, but don’t add much. Maybe a couple inches? If you’re planting root vegetables they’ll want loose soil a foot deep, deeper for something like potatoes.

Wood chips will eventually decay and add organic matter to your raised beds. Decaying wood leaches nitrogen from the soil, which you don’t want especially if you’re growing vegetables.

No matter what you put in the bottom raised beds will need more watering than regular gardens. If the raised beds don’t have totally open bottoms and you’re using something like livestock tanks drill big holes in the bottom. Drainage is essential to plant health.

Good luck.