Square foot gardening is a buzzword in the gardening world that has been around for decades, for many good reasons. It’s revolutionised small space gardening everywhere, and today schools in many countries, around the world, as well as international humanitarian groups, are using the square foot gardening method to alleviate poverty and hunger.
The basic concept was popularized in 1981 by Mel Bartholomew, a retired engineer. In his experiences as an urban planner, and a hobby gardener, he brought attention to the less efficient productive methods of traditional single-row gardening; and by combining his city planning skills with his green thumb he came up with the ever-practical square foot garden.
Mel’s ingenious planting method is based on using square foot blocks of garden space instead of long rows of vegetables. He first devised a 4×4 square feet raised plant bed with a grid, divided into 16 one-foot squares, wherein he planted his crops. Once the system is installed and running, this method is estimated to cost 50% less compared to single row gardening, and it uses up to 20% less space. Little or no fertilisers are required, no heavy tools are needed, weeds are kept at a minimum and best of all much less water is used.
In our metric system 1 foot = 30,48cm, so it is easier to round it up to 40cm. And if you do not have the space to do such a large area with 16 squares, you can make your grids in a single long line, in fact you can shape your grids to suit your space, so don’t get hung-up on the shape of your garden, but rather on the logic behind this method.
It is well known that raised beds work well for growing vegetables, and is recommended with this method, but of course raised beds can have a high initial cost, as you will have to secure materials for your raised bed and purchase soil, and these costs can easily add up.
If your budget is tight but you want to build raised beds, the initial expenses need not be high, as you may find useable materials lying around the garden and home. There are many materials you can use to build your raised bed, such as wood, brick, cement blocks, vinyl or recycled plastic, and the beds do not need to be that high, 15cm will do, so look for the most feasible option.
If you have good, fertile soil, you don’t even have to build raised beds at all to have a successful square foot garden. It’s the basic concept that is important, and you can simply amend your soil and measure out a grid with string or other inexpensive materials. This, together with careful planning, can have a huge impact on how much food you grow, and how much waste you can avoid.
This revolutionary yet simple method was so successful that it inspired Mel to write his first book: “Square Foot Gardening” - A New Way to Garden in Less Space with Less Work. The book created much excitement and its first edition is known as one of America’s bestselling gardening books of all time, with over a million copies sold.
Decades later, the continued popularity of the book inspired the long-awaited update, which was released in 2013 as “All New Square Foot Gardening ” which explores many of today’s hot gardening trends, including vertical gardening, companion planting, pest control, and gardening with your kids. The book quickly received worldwide recognition and was written about in every major newspaper and gardening magazine.
This latest edition is considered to be the biggest selling garden book in America, and is inspiring a whole new generation of gardeners because this method of gardening is timeless, a classic that’s still relevant at a time when food issues are at the forefront of household concerns. Even now, Mel Bartholomew sporadically updates his concept with information on new techniques and beneficial trends in line with modern gardening trends.
I hope to inspire South African gardeners of all ages, and especially those involved in schools, orphanages, and other humanitarian projects to embrace square foot gardening – using this concept can help to alleviate hunger and extreme poverty here at home.
Square foot garden grid Picture courtesy baigné par le soleil from flickrSimple steps to building a square foot garden
Step 1: Prepare your growing space
Bear in mind that you can amend the size of your grid to suit your needs, and the only reason that the most common configuration for square foot raised garden beds is 4x4 feet is because this size divides easily into a grid of sixteen 1x1-foot squares, resulting in a really neat and organised space.
Plus, four feet is also the width that’s most comfortable for most of us to reach into the middle of the bed with ease and without stepping on the soil. Plant roots need air to grow well, and compaction of the soil by walking on it continually destroys these air spaces. So, if you have shorter or longer arms, make your beds as wide as is comfortable for you to reach into the middle with ease. Using the metric system, you can round up or down from 4x4 feet, and make your grid squares 30cm or even 40cm.
You can create a square foot garden, be it at ground level or using raised beds, but in some circumstances raised beds make sense, and are essential if you have very poorly draining soil, or perhaps very sandy or rocky soil.
You can make your garden almost anywhere it will receive 6 to 8 hours of direct sun per day, and where the ground is relatively flat and drainage is good. Avoid low areas that may turn into puddles after hard rain, and you may want to choose a spot near your house to make watering, weeding, harvesting, and other garden chores more convenient and harder to overlook.
To create your square foot garden layout, be it raised or not, you also need to plan where your pathways will be. Ensure that they are wide enough for good access, perhaps even wide enough for a small wheelbarrow to fit through.
If you garden soil is good and you are not building raised beds, simply dig the soil over with added compost or kraal manure. If you are building raised beds on top of the soil, preparing the soil well at ground level is also a good idea, so dig it over and amend it with compost before levelling it out and building your raised bed with a grid on top. This will allow you to plant crops with deeper roots, as they will be able to penetrate the soil easily. For most small to medium sized crops you can start by making your sides at least 15 to 20cm deep, but for larger growing crops or for root vegetables such as long carrots, sides that are 30cm deep would be better.
Depending on what you have used to build your raised beds, you may have to line the sides with landscaper fabric or heavy duty plastic to prevent soil escaping through cracks You may even consider installing a drip irrigation system, which can be made with PVC pipes that divide the bed into the square sections to form the grid, and which double up as a watering system.
Just using the intensive block method of planting your crops rather than planting them in long rows will save you a lot of space. It’s extremely simple, and if you have all the materials you need, you’ll be ready to plant in one afternoon, and in no time you will be harvesting your own fresh produce.
Step 2: Fill your raised beds with growing medium
In the book there is a recipe for a soil mixture using equal quantities of sphagnum peat moss, coarse grade vermiculite, and compost, called “Mel's Mix”, and there's no doubt that it makes an excellent soil for vegetables . However, two of the three ingredients recommended come from non-renewable sources. Peat takes thousands of years to develop and is a valuable natural sink for greenhouse gases; and for this reason farming of this valuable commodity is now banned in some countries. Vermiculite is also mined and therefore also a non-renewable resource with a significant carbon footprint. For these reasons many gardeners refuse to use peat or vermiculite in their gardens.
This should not discourage you from using this method though, as you can use 100% recycled compost, and even some mature kraal manure in the beds instead of Mel's Mix, and if you wish you can add coir, vermiculite or palm peat to improve the texture of the soil.
Mix enough soil to fill the frame. You'll need 8 cubic feet to fill a bed with 6-inch sides, and 16 cubic feet to fill a bed with 12-inch sides. On average, one cubic meter of compost weighs 956 lbs (434 kg). To calculate according to your specific measurements I found GIGA calculator, and with their easy to use topsoil calculator you can easily estimate how much soil (topsoil) in tons or tonnes, or volume (cu ft, cubic yards or cubic meters) you will need for a given gardening project. Given bag size, it also calculates the number of bags of soil you will need. Click here to find GIGA calculator
Step 3: Lay out your grid
The layout of the grid is one of the easiest preparations to do, but the most important feature of a square foot garden, as it lets you clearly see how to space your seeds or plants and keeps your garden looking neat and organized.
Square foot gardening typically starts with a 4x4-foot raised garden bed which is filled with amended soil, before being subdivided into 1-foot squares with markers like lattice strips. Use your material of choice, as grids can be made inexpensively from string, thin strips of wood, dowels, and even old venetian blinds. Lay the grid on top of your bed, and you are ready to start planting.
What to plant in a square foot garden
Once you have your beds laid out, it’s time to plant, and you’ll need to properly space your plants or seeds in each square. How many plants you can fit in will depend on the size of the mature plant, so check the labels on seedling trays or packets of seeds before planting. Obviously, the smaller the plants are, the more you can fit in one square foot. Use a ruler or tape measure while planting to space your plants correctly.
Many herbs and vegetables like perpetual lettuce and spinach or Swiss chard can be harvested continually, and will therefore not take up as much space as indicated for a mature specimen. These types of crops can be planted closer together than the recommended spacing.
Although many vegetables can be grown with this method, the grid squares will not be big enough to accommodate larger growing vegetables like potatoes, and perennials like artichokes and rhubarb that take up a lot of space and need their roots to reach deeply into the soil. Smaller growing crops are the way to go with this method, and today we have a good selection of baby veggies as well.
Square foot garden layout charts are available for download online which can be a great help to give you an idea of how many vegetables can be grown in a single block.
Click here to find square foot garden charts for plant spacing
One square foot can also contain one, or a variety of crops, depending on the type and the size of the plant, and the row spacing required for mature crops.
For taller types of plants, like climbing peas or beans that require trellises, these are placed on the side to prevent shading out small plants, and they are planted in two mini-rows of 4 per square.
Once a square foot is harvested, a different crop is planted for crop rotation and continual harvests, as well as to discourage pests.
If you are sowing seeds, and want a continual harvest, you may want to start as many as you can in seedling trays. Larger seeds can also be started in trays, or planted one by one directly into the grid at the correct spacing. For some crops it may be feasible to purchase trays of seedling from a garden centre to extend the harvest.
Maintaining your garden
Although, square-foot gardening may take a little less work than traditional gardening, you still have to pay attention to your produce.
You need to water when the soil feels dry, but you won't waste water on any exposed soil between traditional rows. Try not to water from overhead, and if you don’t have drip irrigation, water by hand. Use a watering can and water each plant individually, pouring the water into the depressions you made when you planted them. Don't panic, it will take less than 10 minutes to water a 4x4-foot garden this way. If your schedule permits, water in the morning, and remember, you will need to water more often on days that are hot or windy because the soil will dry out faster.
Although weeding is kept to a minimum with this method, weeds will appear so plan on weeding every week. Instead of pulling them up by the roots or using a hoe, simply use scissors to cut the weeds off at their base. (You don't want to disturb the roots of vegetables growing nearby.)
Because weeds won't compete with your vegetables for nutrients, you probably won't need to fertilise, however including a feeding programme won’t do any harm.
Pest Control
Inspect your garden daily to spot insect trouble early. Either hand-pick and destroy insects or spray the soft-bodied ones with insecticidal soap, and knock aphids off of plants by spraying them with a hose.
I hope this article will inspire you to try your hand at growing more edibles at home, and if you do not have Mel’s book, there is a whole lot of free information available online, so do some of your own research on this subject. Adapt this method to meet your needs and you are sure to have success.
My e-book “Growing Vegetables in South Africa” will help a lot too. It’s been selling consistently since 2009 and is affordable for everyone. Click here to read more.