The Garden Decoder: What Is ‘Square Foot Gardening’?

People are always apoplectic when they discover I’ve never seen a seminal movie like Rocky or Caddyshack before. I imagine that’s how some gardeners will feel when I reveal that I’d never heard of “square foot gardening” until last week, when a colleague casually suggested I write about the popular low-maintenance technique for small gardens.

Their outrage would be warranted. The book Square Foot Gardening was published in 1981 (a third edition just came out a few weeks ago) and since then, more than 2.5 million copies have found their way into the hands of gardeners, mostly beginners, all over the world. That first book spun off a host of others, including Square Foot Gardening with Kids and Square Foot Gardening: Growing Perfect Vegetables. And at the height of its popularity, there was an entire series on PBS devoted to the method. The show lasted six years! There’s even a Square Foot Gardening Foundation, created to teach self-reliance and to “solve world hunger one square at a time.”

What’s so revolutionary about this low-maintenance gardening system? And who invented it? Read on.

N.B.: Featured photograph by Erin Boyle.

What is square foot gardening?

Square foot gardening is an alternative to the conventional method of row gardening. Instead of alternating rows of plants with paths, the genius method involves building a small raised vegetable garden (measuring, say, 4 by 4 feet), dividing it into 12-by-12-inch plots (thus the name), and then planting each square foot as densely as possible with vegetables. This maximizes the crop yield in a small space. Whereas row gardening is ideal for commercial farmers who need to use tractors, square foot gardening is geared toward “backyard gardeners” and others who have limited outdoor space.

Who invented square foot gardening?

You can read all about the father of square foot gardening, Mel Bartholomew, in this New York Times obituary (he died in 2016), but here’s an overview. Bartholomew was an engineer who applied his problem-solving mind to gardening after he retired. “It became a challenge to find an easy, fool-proof, continual-garden method that would work in small spaces and require less work, with a high yield,” he told the Times in a 1996 interview. He estimated that, by getting rid of paths, a square foot garden required just 20 percent of the space of a traditional garden—and, thus, just 20 percent of the labor.

How does it work?

Most of the work required is upfront. After the grid is built and the seeds planted, there should be minimal weeding (because, ideally, the vegetables-packed garden will have no room for weeds). Here is roughly how to start a square foot garden:

1. Build a small raised bed out of untreated wood. Common dimensions are 4 by 4 feet and 4 by 8 feet.
2. Lay down a weed mat if the bed is directly on top of existing soil.
3. Fill the box with a mix of 1/3 peat moss, 1/3 vermiculite, and 1/3 compost. (Go here for a soil calculator.)
4. Put down a grid of 12-inch squares; you can make the grid cheaply using Venetian blinds or wood lath from home improvement stores. Then start planting.

What are the benefits of square foot gardening?

Literally anyone with outdoor space can start a square foot garden—even if that outdoor space is covered in pavement—because the method relies on a raised garden box. And, because the garden doesn’t have real soil, there will be minimal, if any, weeding required. But the best argument for this method is that it maximizes crop output in minimal spaces: According to Bartholomew, you can grow an average of eight vegetables in a square (depending on the type), which means a 4-by-4-foot garden (which has 16 squares) can grown an average of 104 vegetables.

What are the drawbacks of square foot gardening?

The two main complaints that crop up about square foot gardening are first, that the suggested 6-inch depth isn’t deep enough for many vegetables (some gardeners recommend simply building a 12-inch-deep bed instead) and second, that it requires more watering because soil in raised beds dries out faster.

For a similar gardening method, see Required Reading: The Postage Stamp Vegetable Garden.

For more beginner gardening advice, see:

•  The Garden Decoder: What Is ‘Lasagna Gardening’?
• Your First Garden: 10 Things to Do in the Garden in December
• The Garden Decoder: What Happens When Edible Plants ‘Bolt’?