University of Illinois Extension

Square Foot Gardens

Do you want to have fresh vegetables, but you don't have the space or time for a large garden," asked Jeff Rugg, a U of I Extension horticulture educator.

"You can grow enough fresh vegetables for one person in a garden that is only four feet by four feet," said Rugg.

"One of the most successful methods of vegetable gardening is the Square Foot Garden developed by Mel Bartholomew, whom you may have seen on TV. He also has a useful book titled All New Square Foot Gardening."

This technique uses a box made from 2x6" boards four feet long. The four foot by four foot box allows for a compact 16 square feet of garden space that can be placed in any sunny spot.

"Last summer, I grew one of my 4'x4' Square Foot Gardens in my office parking lot to show that they can grow anywhere," he said.

"The parking lot had plenty of sunlight and was close enough to the building so that the hose would reach. Garden vegetables produce best when they have lots of light and lots of water. If you have no choice, build it wherever you can, but if possible give it lots of light and water."

Building a Square Foot Garden is easy. Using treated lumber is not recommended, because the chemicals may leach into the garden soil. The boards can be cut to the four foot length at the lumber yard, so they easily fit in a car. Painted with outdoor house paint the boards will last many years. It is easy to add a trellis to a Square Foot Garden, so that peas, cucumber and other vines can grow up.

"The soil used in the box is an eight cubic foot mix of one third peat moss, one third compost and one third vermiculite," said Rugg. "This creates a well-drained soil that still holds plenty of moisture for fruit growth.

"Almost all roots on vegetable plants grow in the top six inches of soil, so the box is plenty deep. Maybe one of the best things is that the soil is weed free. Many traditional gardens are lost in midsummer at the peak of harvest because too many weeds discourage the gardener and reduce the production."

If the spot you are going to place the garden is an existing lawn or weed patch, cover the square with four or more layers of newspaper, a weed barrier cloth from the nursery or just a piece of cloth. Don't use a sheet of plastic because it won't drain and if you poke holes in it to drain, the weeds will come up through the holes.

There is a cost to building the box and buying the soil mixture, but it is probably less that starting a new garden in the back yard. It has a higher success rate than a typical garden that will help you want to stay in gardening rather than giving up. If you decide you like vegetable gardening and want a bigger one, you can add more Square Foot Gardens or make it longer. Keep one dimension a maximum of four feet for easy access to the middle without wasting garden space in an aisle.

"Traditional gardens are often built with large aisles, partly to allow for good air circulation, partly for easy tilling of weeds and partly to allow for the growth of spreading plants," he said. "Small space gardening uses vegetable varieties that have a compact growth habit. You will see these smaller plants listed in the seed catalog or on a nursery sign as petite, bush, compact or determinate.

"There are several benefits to using this gardening technique. The garden can be built close to the house and a water source. It uses fresh sterile soil, so there are fewer weeds. But, one of the most important features of a Square Foot Garden is managing it one square foot at a time. As each crop finishes in a square foot, a new one is installed. There is no wasted space in a Square Foot Garden and production is much higher."