Square foot gardening is the name given to an intensive gardening method that employs specifically-sized raised gardening beds. The plots are a maximum of 4 feet wide by any chosen length, although 4×4, 4×6 and 4×8 tend to be the most popular choices. Some beds I have seen measure up to 4×16!
The growing area is sub-divided into a grid of one foot squares either with twine or bamboo guide markers.
Square foot gardening is generally based on raised bed gardening principals.
Getting Started with Square Foot Gardening
The first thing to consider is where you’ll put your square foot gardens. Pick an open spot that gets enough sun for the plants you intent to put in. Typically an area with 8 hours or more of sun is ideal. Then you need to actually build your boxes. Rachel at Grow a Good Life has an excellent tutorial on building square foot gardening boxes.
Build Your Soil
Combine 1 part peat moss (or coco coir) 1 part coarse vermiculite (or perlite if you have to) and 1 part blended compost. Homemade compost is best, but if you have to use bagged compost, be sure it is good quality (like organic earthworm castings) and not filled with peat moss.
The initial outlay can be expensive (especially if you don’t use home made compost) but it’s good for life. When you buy bagged soil you need to replace it every couple of years or heavily amend it and use fertilizers.
With square foot gardening, you add a trowel of blended compost to an individual square each time you harvest a square, and that’s all. Also, since the bed is so fertile, it only needs to be 6″ deep. If you you want to grow deeper veggies, you can make a 1 square foot “top hat” (as seen at the bottom of this post) and fill that with Mel’s Mix. That way you don’t have the expense of filling an entire bed 12″ deep.
Smaller beds can be made with a plywood bottom (with drainage holes) and put on legs so that those who can’t bend over or who are confined to a wheelchair can still enjoy gardening.
Little to No Soil Compression
The reason behind the plots being 4 feet wide is so you can comfortably reach into the center of the plot from both sides (2 feet from either side), which makes harvesting your crops a breeze! It also means that you never have to tread on the growing area and cause any compacting of the soil.
Less soil compression means the roots can travel further and more freely making for a strong base. The stronger the base roots, the more easily water and nutrients are taken into the plant making for a stronger, healthier plant and a better harvest.
Measured Distribution of Plants per Square Foot
In each square foot area, seeds of the same type are planted in a precisely measured way to prevent over-planting or crowding, and the need to thin out the plants afterwards is greatly reduced. This keeps the number of seeds used to a minimum, and also minimizes cost.
If the seed packet says to sow seeds 12 inches apart, plant one plant in each square foot. If it says 6 inches apart, then plant four per square foot. Instructions to seed 4 inches apart means you can plant nine plants per square foot, and 3 inches apart means you can plant sixteen plants in a square foot plot. After you lay out your grid, you can measure out each plant with a ruler, or you can use this awesome tool to make your measuring much faster and easier.
The basic principal is that for each square foot, the number of seeds planted is dictated by the size of the plant:
- Large plants (basil, broccoli, Florence fennel, tomato, etc) = 1 per square
- Medium large plants (lettuce, beets, parsley, celery etc) = 4 per square
- Medium – small plants (spinach, spring cabbage etc) = 9 per square foot
- Small plants (carrots, turnip, onions etc) = 16 plants per square foot
Climbing Plants in the Square Foot Garden
As a general rule, look at the instructions on your seed packet. When it comes to the heavier fruits, you can support them with a sling made from old t-shirts or pantyhose tied to the support system to keep them from pulling down too hard on the vines.
Germination of Seeds
In most cases with square foot gardening, when planting the seeds, only 1 or 2 seeds are needed to ensure germination, but in the case of carrots and parsnips, 3-4 seeds per hole may be required to ensure at least one will germinate. If more than one seedling appears, they need to be thinned by snipping off all but one. Pulling them out is not an option as it may disturb the delicate roots of the chosen survivor, so be sure to use a sharp pair of garden snips.
Keep in mind, if you are direct sowing your seeds, make sure the soil temp is high enough to encourage germination. Frozen ground or cold soil will prohibit growth.
More Benefits of Square Foot Gardening
- Provides maximum yields for the smallest amount of growing space.
- Provides high quality growing conditions.
- There is a distinct lack of weeds – any weeding is a quick & painless process.
- Low disease risk – having a large variety of plants in a confined space helps prevents disease spreading.
- Better control over soil conditions.
For more information on square foot gardening, check out Mel Bartholomew’s book “All New Square Foot Gardening, Second Edition: The Revolutionary Way to Grow More In Less Space“. Mel gives you every hint and piece of advice to make your square foot garden the best it can be!