Having good soil for your garden plants is absolutely critical, so give it the attention it deserves. In the Square Foot Garden book, the author, Mel Bartholomew, recommends Mel’s Mix. It is a combination of the following ingredients:
- 1/3 peat moss (or coco coir)
- 1/3 coarse vermiculite
- and 1/3 of a good blended compost made from at least 5 different sources, if possible
DIY Soil Mix
You can buy the mix or make it yourself. We opted to make our own garden soil mix. Here’s how.
We used the calculator on the SFG website to calculate how much total soil we’ll need. After inputting length, width and height of the boxes, the calculator will provide the total cubic feet of soil needed. For us, the calculation went like this:
- 2 each 8 x 3 SFG boxes: 8′ (length) x 3′ (width) * 6″ (height) = 12 cubic feet/box x 2 = 24 cf
- 1 each 2 x 2 SFG box: 2′ x 2′ x 6″ = 2 cf
- Total for SFG = 26 cf
We also needed soil for 6 pots of approximately 3 gallons each, which is approximately 2.4 cubic feet total (3 gallons = 0.40 cf). We rounded up a bit and decided to make 30 cubic feet of soil mix and use it for both planters and pots. That made the breakdown of materials easy – 10 cf each of peat moss, vermiculite and compost.
We purchased peat moss and vermiculite from the store. For compost, we got lucky and got all of it for free. The weekend we were planning to mix the soil, Athens (our waste service provider), was giving out free compost to the residents in the city. They do this annually, I believe, and the timing was perfect. We gathered saved potting soil bags and 5 gallon buckets from a bakery – we knew someone there and they saved some of their leftover dough buckets for us; they’re food grade, too, which was perfect.
On compost day, we filled them up, brought them home, mixed in the first batch and then went and refilled them for the second batch. The compost from Athens was organic but it wasn’t the blend that Mel recommends. It’s mostly yard clippings that Athens collects from our city and neighboring area. Our compost bin (more on this is a future post) didn’t have nearly enough compost ready for us to use, so we added some extra potting soil to the mix.
We used about 2/3 compost and 1/3 organic potting soil for the 1/3 recommended compost. This way, we have leftover compost to use in the future for new plants or to add to current ones. On an ongoing basis, the SFG book recommends adding a trowel of compost to each square after harvest, which is what we intend to do.