Square Foot Gardening has taken the home vegetable garden world by storm, and with good reason. It is a great way to manage succession planting and crop rotation in a small family garden. The book offers a lot of great information, but to be successful using this system on the Gulf Coast, a few modifications have to be made. We call this “Square Foot Gardening – Not by the Book”.
The biggest change is the soil. “Mel’s Mix” is made up of 1/3 peat moss, 1/3 vermiculite and 1/3 compost. This mix performs poorly in our climate. It does not fully support the Soil Food Web – the complex biosphere of macro- and micro-organisms that keep soil and plants healthy. It dries too quickly in our heat. It breaks down in a few short seasons in our semi-tropical climate. Vermiculite is a poor choice to preserve pore spaces – it disintegrates quickly into fine particles. And Mel’s Mix does not supply the minerals required to produce nutrient dense veggies & fruits – a major goal of home gardening.
Bed mixes for SFG should be compost based, not peat based. It should contain quality aggregates to preserve pore spaces. The simplest way to get great SFG soil is to use Arbor Gate Organic Soil Complete. It has everything required, including those all important minerals and microbial foods. No measuring, mixing, balancing, or guessing. It’s ready to go right from the bag or shovel full.
Start with vegetable garden mix, which is equal parts topsoil, sand, and compost. On its own, this is too heavy for SFG. Add a MINIMUM of 30% more compost.
You can make a suitable bed mix using 2/3 Leaf mold compost and 1/3 Expanded shale.
Options 2 & 3 require the addition of a rock mineral and dried molasses for optimum soil health and nutrient levels. With all SFG beds, use 1-cup of Arbor Gate Organic Blend per square foot when the beds are built, and replace the spent nutrients between crops with ½ cup per square foot.
No weed mat, please!
Our second recommendation is that you do not line the bottom of the boxes with weed mat. When you build your beds, line the bottom with decomposable sheet products such as cardboard or newspaper. This will kill the grass below, but will eventually decompose and allow the roots of your veggies to penetrate the native soil and for earthworms and other macro-organisms to aerate and fertilize your SFG beds. The native soil will slowly improve as well over time, giving you a rich, deep root zone.
Already built your SFG with Mel’s Mix?
Not to worry. Buy several bags of Arbor Gate Organic Soil Complete. Each time you replant a square, replace Mel’s Mix in that square. Soon, your entire Square Foot Garden will have healthy, living soil.
Angela, I live in central Texas (near Burnet) Does the “not by the book” method of soil preparation apply to this area for SFG?
Yes, “not by the book” applies throughout Texas. To produce nutritionally dense veggies and fruits, the soil must be teeming with microbial life and minerals. It should have good moisture retention, but should drain well. It should have adequate pore spaces to provide oxygen and assist moisture balance. Peat moss and vermiculite offer a root hold, but neither contributes to plant health. One of the three options in the blog will work for you, minding that 30% additional compost really is a minimum in Option 2. I have used 50% – 60% with good results. This compost should come from a professional soil yard, as many mass-merchandised products are inadequate.