Can you use a piece of plywood instead of a box spring?

Yes, you can use a piece of plywood to provide support for your mattress instead of a box spring. However, it is important to make sure that the plywood is smooth and does not have any sharp edges that could damage the mattress. Additionally, using plywood may make your mattress firmer, so you may need to use additional padding or a different type of mattress (if necessary) to adjust the feel of your mattress.