So, let me state right here that I am a pretty lazy person and a lazy gardener in particular. I'm also pretty short in stature and physically fairly wimpy. I don't mind getting my hands dirty, but I am opposed to sweating. So, although it was still a lot of work to set up raised beds, the alternative of creating soil directly in the sand would have been way more work. With raised beds, the precious and sometimes pricey ingredients all stay where the plants are and I don't have to worry about wasting as much of it.
My raised beds are pretty simple. Each one consists of 6 - 1 in x12 in x8 ft pressure treated boards and one 4 in x 4 in x 8 ft pressure treated fence post. Not particularly environmentally friendly and you might want to consider something less toxic for your vegetable beds, but my readings have been inconclusive on just how much of a danger it is to raise food in such a bed. The beds are 4 ft x 8 ft x 2 ft tall. They aren't exactly square in the corners, but they are "close enough" for me. Sorry, the instructions are kind of lame - my husband did the actual building, and I am trying to recall how he did them from two years ago...
- Cut 2 of the 1 in x12 in x8 ft boards in half (Home Depot will do the cutting for you)
- Cut the fence post into 4 pieces
- Set a long board where you want one of the sides and nail or screw two fence post pieces to each end, with one foot extending up
- Nail or screw a short piece of board to the fence posts
- Add a fence post piece to each short board
- Add the second long piece to close off the rectangle
- Fasten a second set of boards on top of that
I filled the beds up to level with the first board with a mixture of 50% native sand and 50% mix of "compost and garden soil from home depot." I was not particularly scientific about it - choosing whatever was on sale at the time. I tried to use more than one brand with the idea that they would have been made from different "base" materials, so that nutrients missing in one would be present in the other. I would have used less sand, but budgetary concerns mandated using more of what we had hanging around - we've got 5 acres of sand.
If I wanted to fill the bed up to the top of the second set of boards, I would have had to put something to keep the dirt from leaking out of the gap between the boards. As it was, the purpose of the second set of boards was to act as a wind break and to give me an area of "partial shade" for more tender plants. This has only sort of worked. As far as a wind break, it works well. However, it gives a little too much shade for most of the seedlings. For example, a cherry tomato plant that I put in the shade languished for several months before it reached enough sun - once it made it to the sun, it took off and started producing little tomatoes - about 3 weeks before the first hard frost. I think 5 actually ripened. We're going to leave the top board off of the ones we build this year and see how it goes.
Although I am moving towards more organic methods, there is such a dearth of nutrients in the sand, that I am currently using a commercial slow release fertilizer. I amend with bone meal and blood meal in the Spring (helps keep the little critters away) and apply fertilizer according to package directions. I am hoping that I will be more successful with my compost pile this year and that I will be able to start using home made & cheap compost as opposed to expensive store bought stuff. To protect that expensive dirt from the sun and the wind, I mulch.