Small Garden Ideas: Square-Foot Gardening

Garden plans and designs for square-foot gardening include companion plants.

Watch your square foot garden plants grow

Settle in, relax and watch your garden do what it does best — grow.

Photo By Jean Fogle

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Square-foot gardening is one of the many great small garden ideas that can simplify the growing process and help train the grower’s focus, eliminating the overwhelmed feeling that some folks face year after year. Every year there are about 15 million people who fit into each of these categories:

• would like to begin gardening.
• tried the traditional single-row gardening method, but failed.
• don’t want to begin gardening because they have heard of all
• the hard work, time and cost associated with gardening.
• are practicing single-row gardening but are tired of the hard work, time and cost associated with this method.
• are unable to continue caring for their big single-row gardens.

Combined, that’s an estimated 75 million people ready for a gardening revolution, compared to about 10 million single-row gardeners who are content with their method and don’t want to change. These statistics come from Mel Bartholomew, who has developed and is a proponent of the square-foot gardening method, a relatively new perspective on gardening that could help you grow more in less space — and with less work. He has been at it since 1976 and has written multiple best-sellers on the topic of square-foot gardening. What follows is excerpted from the second edition of his All New Square Foot Gardening

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How it all works

Square-foot gardening is taking a grid and dividing it into more manageable parcels, planting and treating each square foot separately, for the most part. A common square-foot garden configuration is a four-block by four-block structure, with each block divided off from the other blocks using thin wood placed on top of the soil surface or some other divider.

Begin by visualizing what you want to harvest. This simple first step prevents you from planting too much. Picture a large plant like a head of cabbage. That single cabbage will take up a whole square foot, so you can only plant one per square foot. It’s the same with broccoli and cauliflower. Let’s go to the opposite end of the spectrum and think of the small plants like radishes. Sixteen can fit into a single square foot.

It’s the same for onions and carrots — 16 per square foot. Yet that’s a 3-inch spacing between plants, which is exactly the same spacing the seed packet recommends thinning to.

Small, medium, large, extra large

Think of typical garden plants as if they were shirt sizes. Shirts come in four basic sizes — small, medium, large and extra large — and so do our plants. It’s that simple.

The extra large, of course, are those that take up the entire square foot — plants like cabbages, peppers, broccoli, cauliflower and geraniums. Next are the large plants — those that can be planted four to a square foot, which equals 6 inches apart. Large plants include leaf lettuce, dwarf marigolds, Swiss chard and parsley.

Further, several crops could be in the one-per-square-foot category if you let them grow to full size, or they can be planted four per square foot if you harvest the outer leaves throughout the season. This category includes parsley, basil, and even the larger heads of leaf lettuce and Swiss chard. Using the square-foot gardening method, you snip and constantly harvest the outer leaves of edible greens so they don’t take up as much space as in a conventional garden.

Medium plants come next. They fit nine to every square foot, which equals 4 inches apart. Medium plants include bush beans, beets and large turnips.

Just because we’re talking about measuring in inches doesn’t mean you have to get out your ruler or yardstick, and you don’t have to do any complicated measuring or figuring either. This is why the grid is handy. When your square foot is bordered by a grid (like a four-by-four configuration), it’s much easier to think one, four, nine, or 16 plants in each square foot.

All you do is draw lines in the soil with your fingers. For one plant per square foot, just poke a hole in the middle of the square with your finger. For four per square foot, draw a vertical and horizontal line dividing the square in half each way. The plants go right in the center of these four smaller squares.

How much to plant

I recommend, especially at the beginning, that you plant only what you want to eat. Occasionally try something new, of course, but especially at first only grow those vegetables and herbs that you normally eat.

Remember, plant each adjoining square foot with a different crop. Why? Here are several reasons:

1. It prevents you from overplanting any one particular item.
2. It allows you to stagger your harvest by planting one square foot this week and another of the same crop in two weeks or so.
3. It promotes conservation, companion planting, crop rotation, and allows better plant hygiene and reduced pest problems.
4. It helps to improve your growing soil.
5. It’s aesthetically pleasing.

It’s worth repeating here that the biggest problem for single-row gardeners has always been “I planted too much. I can’t take care of it. It’s too much work, and I’m sorry now.” All that has changed with square-foot gardening, and you now have boundaries (the grid) and the opportunity to ask yourself, “For every single square foot I plant, is that enough? Do I really want more? Would it be better to plant another square foot of the same thing in a week or two or three?”

Plan on a fall crop

As soon as the summer crop is finished, you’re ready to plant cool-weather crops for the upcoming fall. These crops are frost-hardy, meaning that both young and mature plants withstand frost. The seeds you plant at the end of summer will sprout quickly since the soil is warmer. Transplants can begin outdoors and grow much faster than the same thing planted in the spring.

The problem with cool-weather plants in the spring is not cool weather but warm weather at harvest time. A plant’s purpose in life is to reproduce seed, and the rising temperatures of an approaching summer make this happen sooner. As it does so, the plant’s whole character changes. Many people don’t realize that plants like lettuce put up a flower stalk, which then goes to seed. If you wait too long to harvest lettuce, the stalk will shoot up, and the same thing happens to other crops like cabbage. The head splits open, a stalk shoots up, develops flowers, and then turns to seed. It’s nature’s way of allowing the plant to reproduce, but the plant’s taste changes when this happens. All the energy goes toward the seed, and the plant itself, as far as taste is concerned, becomes rather tough, coarse and bitter.

In cooler weather, this process is delayed. The plant feels no urgency to complete the growing cycle. So in the fall, the plant slows its maturation process, allowing it to maintain flavor for a longer length of time as temperatures continue to grow cooler and cooler. If it’s frost-hardy, it doesn’t matter if it is the middle of fall and you start getting frost. Some plants, like carrots, can endure some freezing and still provide a crop for harvesting. Fall is a great time to plant if you put in the right crops.

Soil temperature

Soil temperatures vastly influence sprouting times. For example, if you plant carrot seeds in the summertime when the temperature of the soil is between 60 and 80 degrees Fahrenheit, the seeds will sprout in less than a week.

But if you plant the same seeds in early spring when the ground temperature is perhaps 40 degrees, they will take a month and a half to sprout. Just another 10 degrees warmer and they will sprout in a little over two weeks.

Keeping records

Many gardeners keep planting data: when, what, and where they plant; how long it takes to sprout; and how well their plants grow. It may sound like a lot of bookkeeping, yet some people enjoy recording their garden data and even set up computerized spreadsheets to make computations from this information.

Spacing

How many plants will fit into a square foot? The numbers are so simple and easy to remember: 1, 4, 9 or 16. If you like math, and who doesn’t, you will recognize right away that these numbers happen to be the squares of 1, 2, 3 and 4. And, in addition to the fact that we’re gardening in square-foot plots, that’s how Square Foot Gardening got its name ... because it’s as simple as one, two, three, four. The number of plants you grow in a square foot depends on a plant’s size when it’s fully grown (See Image Gallery). You can also figure it out very easily from the “thin to” directions on a seed packet.

A typical garden

Let’s plant one four-by-four square-foot garden and see how much we will grow in those 16 square feet. We’ll start with tall plants on the north side of the box so they don’t shade shorter plants. Then put some colorful flowers in each corner. Let’s assume it is still springtime, but that we’re past the last frost, so we could put four pansies in each corner using our favorite colors.

Carrots require little care until they’re harvested. So let’s plant two squares of different carrots in the center squares, one square of 16 onions, and a low-maintenance square of 16 radishes in the center. Then we’ll put one square of nine beets in an outside square because we’ll harvest their leaves during the season and then finally pull the beet bottoms later. We can plant two or three varieties of leaf lettuce on the outside, depending on your tastes. In another square we could put 16 chives, and four parsley plants in another, which would provide us a continual harvest. For more color, we might want to put a square of red salvia along the back. And perhaps in one corner some dwarf dahlias, one per square foot. Or perhaps some nasturtiums spaced at one per square foot.

One of the first things we would have planted in the spring is one or two squares of spinach, nine per square foot. Then depending on your family’s taste, we could have one or more squares from the cabbage family. That could be red or green cabbage, broccoli, or cauliflower. Keep in mind this is not the only four-by-four in the whole garden. So we don’t have to put all the cabbage into it. It’s better to space them out throughout the garden — makes it harder for the cabbage moth to find them all.

Replanting

As soon as you harvest, it won’t be a big deal to replant because you’re going to do it one square foot at a time. Once your newly planted garden starts maturing in the spring — for example, that square foot of radishes will be ready to harvest in four weeks — you’ll be ready to replant just that one square. The season has changed and it’s warmer, and most of your summer crops can now be planted.

As you replant, keep the same criteria in mind — taller plants on the north side to keep them from shading other plants, working your way to cascading flowers on the front corners to look pretty. Place plants that don’t need much attention and only occasional harvesting like peppers on the inside, and shorter plants and those that need constant care or harvest to the outside, just to make them easier to tend.

Harvesting

Keep in mind that we harvest many of the crops continuously, if possible. For example, a leaf lettuce is not allowed to wait until it forms a large, mature head, but with a pair of scissors and a salad bowl you can continuously trim the leaves from such things as lettuce, chives, beets, Swiss chard, spinach, parsley, and even onion tops. As long as you don’t take too much at one time, the plant will easily survive and thrive.

You’ve learned the basics

You’ve now learned all the basics of Square Foot Gardening. You’ve learned how it got its name — from the squares of one, two, three, four. You have also learned how many and what kind of plants fit into a square foot by memorizing, calculating, or by looking it up on the chart or seed packet. You’ve learned how to zip zap in the soil to get the proper and exact spacing then start planting your seeds and transplants.

OK, now it’s time to go out to your garden and do something outrageous that will amaze or dumbfound any neighbor who might be watching you. Do you know how to do a rain dance?  

Excerpted with permission from All New Square Foot Gardening, 2nd Edition, by Mel Bartholomew (Cool Springs Press, 2013). To order, visit the GRIT bookstore.