As urban gardens become more popular, small space gardening to maximize efficiency in a small spaces is a hot topic. This approach is not only space-efficient but produces less waste while growing a variety of edible plants.
Learn more about how to bring a square foot garden to your backyard.
What Is a Square Foot Garden?
A square foot garden is a raised bed garden divided into squares for planting a large number of food crops in a small space. Coined by civil engineer and urban planner Mel Bartholomew in 1981, square foot gardens are only growing in popularity.
Traditional row-planted gardens tend to need a great deal of room, and often need large amounts of soil and various support structures, while the square foot garden makes use of a more condensed area. The raised beds of a square foot garden are also a good method for locations with poor quality soil, as fresh garden soil can be added at an appropriate depth for growing vegetables.
What to Grow in a Square Foot Garden
You can grow virtually anything in a square foot garden that you'd grow in a vegetable garden. To make maximum use of the raised beds, it's important to know how big your plants will get. Perennial vegetables such as rhubarb or asparagus may not be a good idea as they just keep increasing in size each year. Raspberries are also not a great idea because they tend to spread invasively, but strawberries are a good choice.
Some varieties of root vegetables grow much larger than others (such as fingerling potatoes compared to russets), so keep this in mind. Speaking of potatoes, they need a lot of space, so consider growing only "new" potatoes (which are harvested while small) or try them in adjacent containers.
Some plants, such as tomatoes, also need a lot of room for their roots, so these might also be better grown in separate containers. But if you decide to plant some tomatoes, plant them at the edge of the bed and create a vertical structure to support the fruits.
Planning a Square Foot Garden
When planning a square foot garden, you need to consider the size of your space, the type of soil, which plants, and the preferred layout of your garden.
What Size Is Best?
One common approach to square-foot gardening is to build 4' x 4' raised beds, but any size will work with this method. The important feature is using string, wire, or other materials to create a lattice or grid of one-foot square blocks to help you plant efficiently. For example, a 4' by 4' bed will have 16 squares for planting, while a 6' by 6' foot bed will have 36 of them. Obviously, the smaller bed is a bit easier to navigate, but do what works best for your location.
What Kind of Soil Is Best?
Raised beds are a blank slate, so choose a good quality garden soil. Your local nursery will have many options, from basic garden soil, to organic vegetable garden soil, to rich "black gold" soils (i.e., soils that are rich in organic materials). You can also mix amendments into your soil (compost, coffee, grounds, crushed eggshells). Potting soil is a bit thin for growing vegetables, but you can mix it with topsoil to improve drainage. A nutrient-rich, well-draining soil is best to help reduce weeds and allow food crops to flourish.
Which Plants to Choose
You can grow any vegetables you wish, as long as they fit into the squares. Try more compact varieties that have words like "baby" or "dwarf" in the name. Keep in mind that cherry tomato plants can get huge. Spring onions, shallots or cipollinis work well. Pick greens when young and small, and harvest often. Herbs are also a great choice for the square foot garden and are happy growing side by side.
How to Space Plants
Some gardeners choose to place all one type of plant in one square foot garden bed (for example, all the greens in one bed). You can also mix different plants together in one bed, using principles of companion planting. Spacing is the main consideration; follow instructions and planting guides for the best results. One square foot may hold ten dwarf kale plants, four pepper plants or six red onions, but only one cauliflower, for example.
Consider Sun and Shade Placement
Since plants will be fairly close together, think about which ones will need the most sun, and which ones could grow with a bit of shade from other plants. For example, you want ample sun on your basil, but your lettuces might enjoy a cool bit of shade in the afternoon. Planting the lettuces so they are in the shade of your basil plants at that time of day ensures a good situation for both of them. There are many shade-tolerant vegetables to help you make the most of your space.
Consider Watering Needs
Different vegetables have different water needs, so this should be a consideration as you decide which plants to put next to each other. Even though your plants will be sharing the same bed, you can adjust the amounts of water they get. Think of the square foot garden sections as small micro-climates with different water needs. Some veggies with lower water needs include okra, zucchini, tomatoes, pole beans and Swiss chard. Cucumbers, spinach, broccoli, radishes, celery, onions, and carrots needs lots of water.
Raised Bed Gardening. University of Missouri Extension.
Sustainable Landscaping. Colorado State Extension.