Building a Planting Bed

About half my yard is of beds made of concrete and stone. The stone came from riverbeds, the desert, etc., and was free for the taking. Where the stone beds weren’t practical, I used Douglas fir, 2” X 12” lumber that I had cut to lengths I needed. I treated that with an insecticide, and the wood held up for about 8 years. By then it was almost rotted through in some places and needed replacing. As I wanted beds that wouldn’t need to be re-built every few years, I invested in a composite lumber, Trex, which cost about twice what lumber would cost, but apparently it will last forever. After 6 years there isn’t even a hint that it might not. I consider it well worth the investment.

If you want a bed of say 20 square feet of planting surface, you’ll need a box of 4 feet wide, and 5 feet long, and 2 feet deep, (Volume = length, times height, times width) you would need (2’ high X4’ wide X5’ long =) 40 cubic feet to fill the box. As most compost comes in 2 cubic foot bags, that would be 20 bags. That would give you one bed of 20 square (4’ X 5’) feet planting area. Those 20 square feet should produce about 200 lbs. of tomatoes in a good season, or 40-50 lbs. of leaf lettuce over a 3-month period, or literally hundreds of Japanese eggplants, or 80 lbs. of zucchini, any combination of the above, or an abundance of whatever it is you want to grow.

You could get by with a planting bed of only 1 foot deep, especially if you have somewhat decent topsoil to begin with. For ease of gardening, an allowance for the soil settling, and a couple inches on top for mulch to protect the soil and hold in moisture, I recommend beds 2 feet high. (That height is very appreciated when you plant, thin, etc., as you don’t have to get down on your hands and knees.)

If possible, you’ll want a mix of good topsoil, compost, and whatever organic matter might be available. The best time to get a bed ready for spring planting is not in the spring, or a week or two before planting. You still might get a decent crop, but it will be many times better if you prepare your bed in the fall. The organic matter needs to break down further through the action of various microbes, fungi, molds, etc