Square Foot Gardening: The Planting Method Created By an Engineer

Bartholemew's view was that traditional gardening with its long rows and wide pathways in between wasted space, water, fertilizer and work. In fact, his conclusion was that row gardens took up about 80 percent more space than they needed to. In order to maximize space, he began using raised beds, divided into a number of 12 x 12 inch (30 x 30 centimeter) squares, each square marked off with string or wood dividers. Each square was dedicated to a specific vegetable — as many plants as were appropriate based on that variety's plant spacing guidelines.

The plants are nestled close together to make less space for weeds. In fact, because SFG doesn't offer up much in the way of disturbed soil, weed seeds are less likely to take hold. Its space efficiency also accounts for its water and resource efficiency — you're only watering and fertilizing the small area that contains the plants you planted.

As with any systematic approach created by an engineer and efficiency expert, there are specific steps to putting together your square foot garden.

Step 1: Choose a Location

As with any garden, the first step involves finding a spot that gets at least six hours of sunlight per day, preferably in the morning and early afternoon when the sun is not as hot. You will also want to consider availability of a water source, as well as general accessibility. One great thing about the SFG system is that a bed can be set up on a table or in a raised bed for those who have trouble squatting and bending — they can even be made wheelchair accessible!

Step 2: Build Your Beds

Next, it's time to create some raised beds made of whatever material you choose, from corrugated metal to lumber. These beds are typically 4 x 4 feet (1.2 x 1.2 meters) and between 6 and 12 inches (15 and 30 centimeters) deep, and all SFG beds have a lattice of 12 inch (30 centimeter) squares placed over them to visually separate the crops.

Step 3: Fill the Beds With Soil

Soil is very important to the SFG system — Bartholemew even claimed that it was the most important part of the method. A ration of one-third compost to coarse vermiculite to peat moss creates soil that feeds your plants, retains the right amount of moisture and creates a loose medium for your plants to grow healthy root systems. Once you've made your soil mix, fill the beds to the brim and tap it down lightly — it's important not to walk on your soil once it's in the beds!

Step 4: Plant Your Veggies

When planting a SFG, spacing of plants is important but very easy. One sector of a SFG can usually accommodate one larger plant like a tomato, pepper or eggplant; four medium-sized plants like lettuce or herbs; or nine smaller plants like radishes, carrots or onions. In some cases, as with microgreens, a square might accommodate 16 plants. There are a few plants like squash, asparagus and cabbage that take up more than one square, and climbing plants like peas and beans may be planted in two small rows of four plants per square.

Instead of thinning unwanted plants by pulling them up by their roots and disturbing the soil, Bartholomew swore by thinning with scissors. Also, try to catch weeds when they're small to minimize soil disruption. Fertilize and water just as you would a regular in-ground garden.

The SFG system is popular and pretty foolproof, but it has its limitations. For instance, it can be expensive to set up on the front end, although using reclaimed materials like lumber, old bricks and cinder blocks to build beds can help. Two-thirds of the soil mixture is made of nonrenewable resources — peat is partially decayed organic material that takes millenia to form, and is a natural sink for greenhouse gasses, and vermiculite is mined material. In addition, SFG doesn't work as well in arid climates because raised beds dry out more quickly.

But whatever its limitations, SFG has gotten millions of people growing their own food who might otherwise have never known the joy of a backyard (or rooftop) garden.