Cost of Building Square Foot Garden

Today Tony is putting up insulation in the bathroom and running the plumbing lines. It's not anything he needs much help with, so I'm working on plans for other things like our square foot garden beds. Since we ended up moving in June instead of May, I'm too late for a spring/summer garden, so I'm planning for a fall garden instead.

Tony's mother has had a garden for years. She has always used cinder blocks as a border and when she downsized her garden just over a year ago, she gave us all her extra blocks. I'm going to simply build one garden at a time and since at the moment we only have enough blocks for one or two beds, I thought I'd price the blocks as well as potting mix.

At our local Home Depot, the blocks run $1.53 for 8" x  8" x 16" blocks and $1.09 for 4" x 8" x 16" blocks. We will need a total of 16 of each type of block to make the bed a depth of 12", for a total cost of $41.92.

For the potting mix, a mixture of 1/3 organic compost, 1/3 peat moss and 1/3 vermiculite is recommended. We will need 16 cubic feet of potting mix to fill each bed, although I plan to go a little less than 16 cubic feet to allow space for mulch. Let's say I do 15 cubic feet just to approximate the cost of potting mix. I will need 5 cubic feet of each component. The organic compost I was viewing didn't give a measurement in cubic feet, so I had to do some math. Just in case you ever need to know, there are 1728 cubic inches in one cubic foot (and to measure cubic inches or feet, multiply length x width x height). Each bag of compost is approximately .5 cubic feet at a cost of $1.67 per bag. The peat moss is 3 cubic feet per bag at a cost of $9.75 per bag. Then the vermiculite holds 2 cubic feet per bag at $19.97 per bag. So I will be needing 10 bags of compost, 3 bags of peat moss and 2 bags of vermiculite for a total cost of $85.89.

This will bring my total cost per bed to $127.81. Now since I will have some leftovers from the bags of peat moss and vermiculite and I do have some cinder blocks on hand, my cost will end up being a little less. It may seem expensive to initially build the beds, and it is, but when I consider how much I spend on fresh produce each week, the cost of each bed will pay for itself in one growing season.