I had a client that wanted to build some nice high raised beds to make gardening easier for himself and so he didn’t have to bend over so far. I can completely understand not wanting to bend over too much when gardening! Because these beds were going to be 15” in depth and they were 3’ x 8’ this would take quite a bit of our Amended Top Soil to fill the beds. I suggested that they fill the bottom of the boxes with a something that could take up space so they didn’t have to buy as much of the soil. This raised the question as to what materials work well to fill in on the bottom of the raised bed boxes. What material will fill space in a raised bed garden? If your raised beds will be deep as in my example above, you may have space enough for some branches that you have gathered from your yard. You can also make a layer of some grass clippings or leaves that you are cleaning up from last year. So don’t throw those away in the green bins! You can think of this as if you are making your own compost. Other suitable materials to take up space that are safe for your planting is rocks, Styrofoam chunks, used pop cans, cardboard, newspaper or straw. The sod you removed when placing the beds is an option if you let it dry out so the grass doesn’t regrow! I realize that acquiring the materials can be cheap or expensive so I’m offering several options. Of course the more natural the material, the more it will break down and form your own compost eventually. The other suggestions won’t break down, but you won’t need as much soil to fill your boxes!