Square-foot gardens are an easily managed, low maintenance type of raised bed that is an alternative to traditional row-gardens. They are perfect for gardeners with little space or for beginning gardeners.
Gardening with raised beds has many advantages, such as the ability to plant in areas with poor drainage. The smaller size of the square-foot gardens also makes garden chores more amenable.
The layout of a square-foot garden usually consists of at least one four foot by four foot planting box with six to eight inch tall sides. Beds larger than four feet wide can be difficult to access from the side for weeding, planting and harvesting. Many different materials are available for constructing the box—naturally rot-resistant cedar boards and synthetic wood are both popular options that are generally available at a local hardware store. If several beds are being used, a three foot aisle between them is recommended.
A mixture of good quality potting soil and compost, or other organic material, is best for raised beds. The soil underneath the bed can be tilled and mixed in as well. Before soil is added, the bottom of the bed should be lined with landscape fabric or newspaper. Soil should be filled to within two to three inches of the top of the sides and leveled without compacting.
After the soil is mixed and added, make a square-foot grid on top of the raised bed. This can be done by laying down sticks or strips of wood or by stringing twine across the bed’s frame. The grid should divide the box into one foot by one foot squares for a total of sixteen squares in a four foot by four foot planting box.
The small squares created by the grid are used instead of rows for dividing planting areas. A different flower, vegetable or herb should be planted in each square.
Plants are placed closer together in raised beds. This intensive gardening increases the vegetable yield per square foot. The closer spacing also enhances weed control since the dense canopy shades out weeds. The idea is to have the plants close enough to just touch but not to compete with one another.
Most of the time there will be room for only one plant in each square, but sometimes there is room for more. Sixteen carrots or onions or four leafy greens like lettuce, spinach, or chard can fit in one square foot.
Raised bed garden have increased drainage, so it is important to provide adequate irrigation, especially in the winter. Water in the mornings to prevent quick evaporation and disease, which can occur when you water in the heat of the day or in the evening. Winter-grown vegetables should receive a total of one to two inches of water per week from rainfall and irrigation combined. It may be useful to install a basic rain gauge near the garden.
Square-foot gardens provide a great opportunity to implement a simple irrigation system such as a soaker hose or drip tape, although a hand-held watering can will be fine as well.
Mulching the planting area is helpful in retaining soil moisture and suppressing weeds. Organic mulches enrich the soil as the mulch decomposes, improving soil structure and slowly releasing nutrients. Mulch should be maintained at a depth of two to three inches but should not touch the plant stems. As mulch decomposes, it should be replenished.
For questions about growing vegetables, garden pests and diseases, and more, contact your local Extension agent.
Adapted and excerpted from:
C. Minch, “Big Ideas for Small Spaces” (618KB pdf), Roots & Shoots, Osceola County Extension (07/2009).
W. Kelley, “Great Vegetable Gardens Often Come in Small Spaces,” Green Garden News, Santa Rosa County Extension (03/2007).
J. McLaughlin and A. Hunsberger, “Raised Beds: A Guide to Raised Bed Gardening in Miami-Dade County, Florida” (1.37MB pdf), Miami-Dade County Extension. (02/2002).