How to Build a Square Foot Garden

by Marcy on May 3, 2014 · 0 comments

how to build a square foot garden


How to Build a Square Foot Garden

This is a guest post written by Kristi.

Square Foot Gardening is the answer to that age old question of how to grow a lot of fruits and vegetables in a relatively small space. Using enriched potting soil, 6-8 hours of sunlight, and good watering techniques you can grow up to 24 plants in one square foot! With square foot gardening the potting soil is the key because of all of the amendments that you add to it. You are able to do successive plantings in one growing season as the plants mature faster and set fruit earlier than in regular gardens.

Here are some tips on How to Build a Square Foot Garden:

Square foot gardens tend to be one of two sizes, either 4×4 or 3×3 with the latter being used if you are building a child-friendly garden so they can reach into the middle of the square. Step one: Use six-inch wide untreated lumber to build the outer square. A key step to this process is to lay down a weed barrier to prevent weeds and grass from growing up into the plants. Plastic trash bags or plastic garden liner from your local hardware store will do. If you are growing your square foot garden on a patio, you can build a bottom onto the large square with plywood. (Know that you will have to change this out every so often as the wood breaks down.)

Step two: Next comes the fun part of creating some super awesome potting soil. The secret to square foot gardening success is in the blend of different materials by using equal parts of bagged organic potting soil or compost, vermiculite, and peat moss. If you use organic potting soil instead of compost, mix a few different types or brands together to give a good variety of nutrients to the mix. Two great brands are Supersoil and Black Gold, stay away from anything with synthetic additives. Every potting soil on the market is made differently and you want to capture those differences for your square foot garden. Add in organic fertilizers to this initial mix as well which is a cup of blood and bone meal and 3 cups of earthworm castings. Now pour this mixture into your pre-made square and water it down well until you can squeeze a handful of the soil and no water drips out. This squeeze test is how you know the water has been completely absorbed.

Step three: Create a 4×4 grid marked off with 12” squares using string or paper, and place it on top of the soil so you know exactly where to plant your seeds or transplants.

Use this is guide to help you know how many plants go into each square:

  • Small: 16 plants per square for 3” spacing
  • Medium: 9 plants per square for 4” spacing
  • Large: 4 per square for 6” spacing
  • Extra Large: 1 per square for 12” spacing

Step four: Plant your seeds! Every seed packet has a planting guideline to know how far to space seeds, but since the soil is amended with square foot gardening, you can tighten up those numbers a bit. For instance if it says to plant carrots 4 inches apart, you can plant them 2 inches apart with this gardening method. They just need enough space to grow – usually 1-2 inches.

If growing tomatoes, peppers, or squash plants remember that they are heavy nutrient eaters so only put one plant or seed into each square. Smaller plants like lettuce or spinach can have 16-24 per square.

Experiment with your square foot garden and try different plants together in different squares to see which plants like to be next to each other. For instance plant carrots which are a root vegetable next to spinach which has a shallow root system. One is growing above the soil and the other below – brilliant!

Note from Marcy: Consider installing plastic garden fencing around your square foot garden if you live in an area with wildlife/animals. We lost several plants in our square foot garden last year to deer and rabbits!

I hope this article gave you some good tips on How to Build a Square Foot Garden. Do you have any tips that you would like to share? Please feel free to leave a comment below.

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