Goatlady,

the pallet slats are pretty tightly spaced, but perfect for drainage so no need to drill holes. The side areas had more space, so we used window screen and recycled soda cartons to line it with and help reduce the amount of soil needed to fill them.

nwalk, I will add a couple more pics that show how nice they actually look when filled and planted. A crafty person could paint and decorate them..
Will mention to DH to come along and post the steps he took to make them, he made it look simple, but that's easy to say when I was only watching, lol

in the background of one of the pics, you can see the water catch system he set up off the side of our old barn to run over to the garden.

ETA: DH is making other boxes less deep to reduce the amount of soil needed to fill them with. Many things don't need alot of depth to grow, but I wanted a variety of sizes. Just make sure you put them where you want them or build them nearby, they are heavy buggers even unfilled, lol
and welcome to the Tree, Nwalk!