Building your own square foot garden (SFG) can be a rewarding experience for anyone, especially people and families looking to have a little more control over the foods they eat. Selecting your crops can be fun and exciting. It’s also a great way to try some new foods you are curious about. Plants grown in a SFG don’t require the use of pesticides and herbicides either, so there’s no worry about potentially harmful effects of added chemicals.
While putting together your SFG might seem laborious at first, it’s something you will only need to do once, and it can be a very rewarding experience for all involved. No one ever said gardening was easy, but you will be pleasantly surprised by how effortless square foot gardening is and how fun it is.
May is a great time to begin constructing your SFG. In Michigan, you’ll be able to plant almost any weather crop. From lettuce to radishes, and tomatoes to eggplant, your possibilities are endless.
First you need to decide on the size and style of your raised bed. Your SFG can be placed directly on top of existing soils, built to sit on top of concrete, or can be elevated on legs.
If you’re interested in a more complex design, there are numerous resources available online and on Pinterest. Today we will focus on the most simple of designs: the basic SFG.
To start, we will begin with the list of materials needed for this project.
Cedar is one of the best options for building your SFG box. Cedar wood is naturally disease- and rot-resistant. This means that the wood isn’t chemically treated. The only downside is price.
Mel Bartholomew, the founder of the Square Foot Gardening Foundation, believes that when building a SFG, you should use whatever materials you have available, and to use resources that are affordable. Personally, I’ve seen boxes made of cinder blocks, composite decking, leftover lumber from construction companies, etc. Use whatever materials work for you, and try to save money where you can.
SFGs use a special type of soil called Mel’s Mix. This soil mix is essential and one of the reasons why SFG is so simple. You only need three ingredients for the mix: peat moss, coarse vermiculite, and a variety of compost.
You mix these three components in equal parts (⅓+⅓+⅓) and the amount you need (in cubic feet) depends on the dimensions of your box. For example, if you have a 4-by-4-foot box, you need a total of 8 cubic feet of all three components. If you round up to 9 cubic feet, the math is a little easier and you can split each component up. This means you will need 3 cubic feet each of peat moss, vermiculite, and compost.
To calculate the required amount of soil, you simply take the dimensions of your box and multiply them together. So for a 4-by-4-foot box, you will multiple 4 feet by 4 feet by .5 foot. (since your box is only 6 inches deep, you will multiply by ½ a foot).
You need to be careful, however! Peat moss is usually sold in a compacted form, so if you purchase a 3-ft3 brick, you will actually have 6-ft3 once it is fluffed out. Be sure to take that conversion into consideration when purchasing your supplies. You also need to be sure to buy the ‘’coarse’’ grade vermiculite, which will keep the soil loose, and help hold more water than the finer grades.
Lastly, be sure to buy a variety of composts, such as chicken, cow, mushroom, etc. Having different sources makes a more nutrient-rich blend that will do a better job of fertilizing your plants. I suggest five different sources, but that can be hard, so do the best you can at finding a variety.
With SFGing you’ll also use vertical space to maximize any available space you have. Plants such as tomatoes, peas, beans, melons, cucumbers and pumpkins can all be grown vertically!
I prefer a 6 feet tall trellis that is around 4 feet wide. This allows my plants to grow high, without being too high for me to reach.
If you are handy, you may use any available materials to design and build your own trellis. Our family uses electrical conduit that you can pick up from any home improvement store (ours measures ½-inch in diameter). The conduit comes in a 10 foot length, so it works out great if you need to cut in those dimensions!
Next, add two elbow connectors at the ends and you have a trellis frame. You can secure the bottom by placing the frame over metal rebar that is fixed into the ground, or you can secure the conduit with clamps that are screwed into the sides of the SFG box.
Once you have your trellis assembled, you can ziptie on trellis netting that can also be purchased at many garden or home improvement stores.
This is one of the most important components of your SFG. Grids need to be permanent and prominent. This is where the term ‟square foot’’ in ‟square foot gardening’’ comes from. Each square will be 1 square foot, and will be your guide for determining not only what you plant, but how much to plant in each square.
A traditional SFG grid is made up of wood lath that is placed both horizontally and vertically across the frame of your SFG. The ends should secure directly into the frame using small screws or nails. If you have trouble finding wood lathe, you may also use twine. In our beds, I placed nails so that they stick up like pegs, to which I then wrap twine around and make into a grid. Again, find something that works for you, but the best grid will be something sturdy!
You may need additional tools once you start your SFG. Luckily, many of you will already have these items on hand!
- Trowel. A small trowel will come in handy when you need to add a scoop of compost into your square after you’ve harvested a crop
- Pencil. When planting your seeds a pencil comes in handy for poking holes into the soil. A finger or two always works great too!
- Small scissors. The kind used by elementary students work well. When planting seeds, you’ll want to be sure to cut back any extra seedlings that emerge.
Examples and Final Notes
Thanks to my amazing friends over at the Square Foot Gardening Facebook page, I was able to provide everyone with some amazing examples of SFGs done in a number of ways. Feel free to join the group if you decide to embark on this amazing gardening adventure, or just want more information.
My next post will focus on planting seeds and transplants. If you decide that you don’t want to wait, go ahead and grab a copy of the All New Square Foot Gardening book, which is the best source of information on building, planting and more. I’m also available for any additional questions!
Good luck and happy gardening!
– Joohi Schrader is a nutrition and food science major at Wayne State University, a mother of three amazing children, and a certified Square Foot Gardening instructor. She’s also a Parenting Program volunteer.