When planning this article, I started by asking myself such questions as “how many onions does a typical adult eat each season” and “how much margin do I need to allow for yield problems such as pest control, weeds, poor watering etc” and finally “what percentage of adults actually eat onions”. Needless to say it was a very calculator-heavy method of divining the required yield for a standard household garden, and at the end of the day totally unreliable because the vegetable needs would vary heavily depending on the individual dietary preferences of each member of the household.
Which was why I was so pleased to find in my background reading that there was someone who had already done the math for me. While there are still some variables, because gardening requires that yields will often be affected by some unplanned factors (such as the arrival of slugs), this gardening layout is highly customisable and also helps you to manage the risks as well as can be expected for an entry level farmer.
There’s this perception that gardening is inherently uneconomic – that in order to produce a decent sized crop to feed yourself and your family, and that is worth the time, labour and money involved in the setup, you need to have a large section of arable land with ideal soil quality and powerful machinery. But, as we shall see in later articles, nothing could be further from the truth.
Square Foot Gardening, created and developed by Mel Bartholomew, has been proven and replicated across the world, and has led to some spectacular simplification of gardening almost regardless of climate. Rather than focusing on maximum output, it focuses on productivity, and getting the most you can from a small plot of land using a logical set of steps that become just about as easy as building Lego.
The gist of Square Foot Gardening is that:
- A single 4 foot by 4 foot garden provides enough leafy vegetables to provide a supply of leafy salad vegetables for one adult for every day of the growing season
- Two square foot gardens provide enough vegetables and salads to feed a single adult every day of the growing season
- Your third square foot garden gives you enough vegetables to satisfy your quirky culinary demands, plus a surplus to give away to the neighbours
- Kids can have their own version of the garden where the same rules apply, except that they only need 3 foot by 3 foot gardens.
I know, I know – you’re probably already having a small seizure over the usage of the antiquated imperial system measurements. But bear with me – some ideas are so good they are worth abandoning the metric system for.
There are many benefits to square foot gardening (far too many to list in this short article), so if you’re interested in the subject you can find out more by reading Mel’s book. In short, however, it means
a) no more time or petrol spent on trips to the veggie market;
b) no more expense on perishable fruit and vegetables; and perhaps best of all for New Zealanders
c) no more Goods and Services Tax on your purchase of the fruit and vegetables you grow because instead of buying them from someone you now grow them yourself.
A square foot garden is a system that eliminates one of the cost nerves experienced by many families. As well as putting a few extra dollars in your pocket each week, it also provides you with a lot of satisfaction and educates the children in your family (and perhaps yourself) about how to set up and manage a garden with minimal fuss. In short, it increases your quality of life, and educates everyone around you about home gardening. Not only that, but it can be used for slightly more nefarious purposes, such as being a drawcard for convincing your grandchildren to visit more often. (Mel’s book has an entire section discussing how you can trick your grandchildren into visiting more often by helping them build a square foot garden at your place.)
So, what does it take to set up and manage a square foot garden?
Setting up
To build the foundation of a square foot garden you need:
1) 121.6cm x 121.6cm (or slightly longer, as a buffer) weed mat
2) 4 raised bed planks of a minimum height of 15cm and length of 121.6cm
3) A lattice or trellis of 6 slats to criss cross over the garden
4) 12 long nails
5) A drill
6) A tape measure
You drill holes in the end of the planks and put the nails through so that they form a perfect square. You then lay out the weed mat on the section where you want to garden, and hold it down with the planks. Finally, you add the trellis posts over the top so that it forms a grid at the one foot mark. If you want to, you can nail in a few stakes in the corners to hold it all in place.
It’s that simple.
The costs will vary depending on where you source your materials, but as a rough guide, the weed mat might cost you about $5 per metre if it’s a custom cut, the planks might cost you about $3.50 each, the whole trellis around $10, the nails around $5 for a bag, and hopefully you can borrow the tape measure and drill. There are ways to get things cheaper – nearby construction sites may have spare timber, you can get lengths of pre-packaged weed mats at a lower cost, and you can often buy downgraded timber on TradeMe in bulk for a couple of dollars plus delivery.
Next, you need to put together a special composite soil alternative called Mel’s Mix. Mel’s mix works out to one third portion of vermiculite, one third portion of peat moss, and one third portion of a blend of at least 5 organic composts. Each of the components to this soil should be measured by volume, NOT by mass (that is, get the bags side by side and roughly compare how much space they take up, rather than going by weight measurements on the pack).
This is the expensive part – a couple of small bags of vermiculite might cost you around $6 per bag. A bale of peat moss can run to $35. Several bags of organic compost might run between $30 and $50.
If you already operate a worm farm, this can be an excellent use of your worm castings. The highly nutrient rich worm castings can be a great alternative to the blended compost as long as you’ve given your worms a variety of different foods to compost. Because it takes time to establish a worm farm and start producing vermicastings, I recommend setting up your worm farm at least three months before setting up your square foot garden to ensure the food has been composted well.
You then mix together the soil components on a tarp and blend them in. After a few minutes’ work you have ‘Mel’s Mix’, a soil substitute used keep out weeds, provide nutrition and retain moisture. Simply spade this into your garden, and you are ready to water and plant.
So for less than $150 you have a platform that you can use to grow your vegetables from home, and it can be used year after year until you leave the property. (And if you do leave the property, the square foot garden is not too difficult to divide and take with you, although it may leave a dead patch of grass in your yard.)
There are all sorts of variations on this setup, so I encourage you to read Mel’s book for more information. The main advantage of the square foot garden is that it helps you to manage space more productively, by allowing you to use width as well as length to squeeze more seeds into ideal spacings within the square foot blocks.
Garden placement
Square foot gardens have been grown on rooftops, on concrete, and on rather small plots of land. While it won’t suit every environment, it’s customisable and small enough to suit many home owners or renters.
Harvest planning
The square foot garden allows you to get maximum variety from a very small space. Within a single square foot (of which the garden holds a total of 16), you can often fit anywhere between one and sixteen plants, depending on the recommended spacing of that plant variety.
A chili plant, because it requires 30-45cm spacing, will often require at least an entire square foot to itself. Radishes, however, can be planted 1cm apart, for a total of 16 within a single square foot. You decide what crops you want to grow and determine productivity and flavour based on the individual plant spacings, which can either be found online or on the back of a seed packet.
It’s very important to sit down and think this step out, because you are anticipating your own needs for vegetables over the next 6 months. It doesn’t make sense to have a whole row of lettuce become available at a time when your fridge is full of lettuce. Nor does it make sense to grow huge quantities of radishes if you don’t even like the vegetable to begin with. But the grid structure of the garden makes it really easy to plan your harvest and space your vegetables accordingly.
Let’s say for example you wanted 16 radishes for a series of salads in week 6 of your season. Since you space radishes 1 inch apart, you simply draw four lines across your square foot and four lines down, leaving a cross cross pattern. You then make a small impression in each mini square and drop a coupe of seeds each in the centre about 5 weeks before you need them.
Low Maintenance Gardening
Another huge advantage of square foot gardening is the virtually nil amount of maintenance required, compared with other types of gardens. You don’t need to do any weeding, as the weed mat prevents weed seeds from rising up through the soil when it is turned, and the Mel’s Mix contains no weed seeds. Mel’s Mix holds water really well, so overwatering is almost impossible. The ease with which you can clear and rotate crops in specific squares also helps to reduce the risk of disease setting in at the root.
On weeks where there’s not much rainfall, you may need to scoop in a little bit of water into each square. Once or so a month you can stop by and pick out a weed if one has taken root. It’s really handy if you can build the garden next to your front door, so that you can keep an eye on things when you leave in the morning. (The closer to the main access points at your home, the better.)
Family benefit
As hinted at above, the square foot garden can be an ideal way to bring a family together. The principles are so simple that anyone at any age can learn them quickly. It doesn’t take much to inspire your family and indeed your neighbourhood to become avid growers.
Environmental benefit
There’s a lot to be said for minimising wastage and fuel consumption by growing vegetables on site. Wherever you stand on the whole ‘fuel miles’ debate, it’s hard to argue that there could be a more environmentally effective mechanism than growing things in your own backyard.
What’s more, Mel recommends that the ideal location to place your garden is just a few feet away from your home or walkway, because you can often manage the watering on your way out the door.
Return on Investment
Let’s assume you build two square foot gardens to take care of all of your veggie needs. The cost of two gardens might come to around $300 (I’ve assumed $150 per garden here; actual costs may come to under $130 depending on your suppliers).
Let’s assume you’re accustomed to eating around $12 of veggies per week, and that the growing season lasts for 25 weeks.
The amount the gardens could save you would be $300 per year. In other words, it pays for itself within a single year, provided you water and harvest correctly.
As usual with these numbers, there is some wonky maths & assumptions involved, so you will need to try it for yourself and see whether you enjoy the process as much as I did and whether it saves you as much money in your context. The worst that can happen is it puts you out a couple of hundred dollars.
Flies in the ointment & other considerations
While it may be hard to see how things could go wrong, the truth is that square foot gardens don’t always work perfectly in practice. Here are some things that you ought to keep in mind.
1) You will need to invest some time in setting up and maintaining the garden
As mentioned above, most of the work goes into the setup. It should be noted that this form of gardening probably requires a little bit more upfront capital than simply cordoning off a section of your back yard and planting some seeds there. But the construction is worth it, because this process of gardening virtually eliminates many of the problems that make gardening such a chore. As a result it often limits the amount of time you need to spend on garden maintenance to a few minutes per week.
2) You are still exposed to pest risks
Certain inbuilt features of the square foot garden minimise the risks of pest and diseases. Encouraging crop rotation in each of the individual squares substantially reduces the chance that disease will set in. The variation in crops in a single square foot garden also means that certain types of pest are less likely to arrive or spread. But pests can still occur, and when they occur, they can reduce your yield substantially.
The best hedge against this is experience. The square foot garden is a great training ground for gardeners, and a little bit of pest management will make you a wiser gardener in the long run. If you are interested in this, Mel’s book contains sections on how to build pest protection for a square foot garden quickly and cheaply.
3) Organic home grown vegetables don’t always turn out perfectly
If you’re expecting your garden to yield perfectly shaped, supermarket style carrots, then you’re in for a disappointment. Organic vegetables don’t always look like that, and you should not expect visual perfection. What you do harvest, however, will be fresher and better for you than what you would pay money for in just about any supermarket.
4) The assumption that the garden can feed you for each week of the growing season depends upon a specific harvesting method, particularly for lettuce
As you will see when you read Mel’s book, the manner in which you pull lettuce from your garden is not the stereotypical “cut the whole thing off” method. Instead, you are harvesting leaves when and if you need them.
This is great, because there are few things more disappointing than buying a lettuce and only getting through a third of it before it starts to go off. Some of us just aren’t as salad-inclined, yet nonetheless experience deep and wringing emotional guilt at having to throw out an otherwise perfectly edible set of lettuce leaves simply because we did not have a need for them. Harvesting the leaves from the plant as you go is a more efficient and less guilt prone solution to this problem.
5) Some certain types of fruit and vegetables require tailored growing environments
Tomatoes, for example, need height, and some root-based crops need a full 30cm, rather than 15cm, of depth. If you plan to grow these crops, there are some interesting workarounds that integrate well with square foot gardening, and you should consult Mel’s book for more information.
6) You need to follow a specific harvesting method
In order to make good on the promise of the square foot garden, you need to follow Mel’s instructions on how to harvest your square foot garden properly. Rather than harvesting a whole lettuce, for example, you might simply snip away a few leaves to use in a salad, then come back a few days more to snip away a few more. If you uproot the whole plant each time it grows, you won’t come close to feeding yourself for a season.
That said, square foot gardening is overall a system that, if not perfect, at least deserves the title of “amazing”, and simplifies complex and exhausting gardening activities into a neat little box.
Tax and inflation benefits
The beauty of it all is that apart from the fun you will have, you will also end up not merely saving yourself some money, but eliminating some of your long term cost base in a highly environmentally efficient way (which is what this blog is all about).
If you are a kiwi, you will jump at the chance of getting yet another break from the all-pervasive Goods and Services Tax, which unfortunately in this country applies across the board to fruit and vegetables as well as other products. You still have to pay GST on the inputs, such as the wood, nails, and soil mix components, but these are a once off capital cost for a saving that may last decades.
Perhaps more importantly, however, running your own vegetable garden saves you from the effects of price fluctuations on the vegetables that you grow. This has a long term benefit of making you less exposed to inflation, and more in control of your own cost base. It also means you potentially have an extra source of local food supply during an earthquake or other emergency.
There is nothing new about square foot gardening. It has been around since the early ’80s and has been gradually refined over time. But to this day it remains a highly productive form of gardening for the entry-level home farmer, and a great way to educate yourself in home gardening and reduce your exposure to inflation at the same time.
Ready to take the next step? Find out more about Square Foot Gardening by reading Mel Bartholomew’s eponymous book.
