How to Build Your Own Square Foot Gardening Box

Spring is her! We have seeds started, we’ve got our gardening gear ready, and we’ve got big plans this year.

We a variation of Square Foot Gardening. Even though I’m not a fan of measuring and calculating, I like knowing that our raised garden beds are maximizing their space.  

Making Your Own SFG Box Plans

Square Foot Gardening Box

The point when your garden physically takes shape is when you build own SFG box because you get to see up close where all the plants will live and grow.

By building your own box, you learn a little something about independence and achievement.

Building your SFG box is a great opportunity to teach kids about using power tools [or any other tools] safely.

The Materials for a Square Foot Gardening Box

Start the great big SFG box adventure by gathering all of the required materials. And, wow, there are a lot of possibilities.

The SFG box can be built out of just about any material as long as it meets certain restrictions.

First and most important: the material cannot contain anything that might contaminate the soil and get into the plants growing there. That means paint or preservatives used to treat wood, or oil-based paints on metal or bricks are no-nos.

  • This especially includes treated lumber, unfortunately. Older, reclaimed treated lumber (the good stuff) is soaked in formaldehyde. Newer stuff that doesn’t last anyways, is soaked in a variety of other toxic chemicals.

Even though you can use many different materials, most people choose wood for good reasons. Wood is a natural, replaceable material, it’s easy to work with, easy to find, inexpensive, and looks good.

Start with what an SFG box must be. We want our box to be:

  • 3 feet x 3 feet.
  • Square.
  • 6 inches deep.
  • Durable.
  • Portable, if we want to move it later.
  • Nice to look at.

So with all that in mind, let’s ask a few questions about what might be the best material for our SFG boxes.

  • Why is wood a good choice for the SFG box?
  • What other materials could we use?
  • What about glass? Could you use glass for the box?

Why or why not?

  • What about metals?
    • What different types of metals are there?
    • Which would be best for a box and why?
  • Where would we find those metals?
    • What would be some of the challenges in using metals?
  • What about bricks or concrete blocks?
    • What would be good or bad about using bricks or concrete blocks?

Generally, wood is going to work best. So the instructions that follow are geared to using wood for a box.

Putting Together a SFG Box

Now that you’ve gathered the materials, it’s time to get organized and build that SFG box. Let’s get started with a few safety rules to make sure this is a happy experience for everyone.

Setting Up Your Work Site

Set up your work site as close as possible to where your SFG box will ultimately go. The best place is a flat, level surface with lots of room to move around.

It’s always a good idea to make an actual staging area. This can be a driveway, a tarp laid out on the grass, or even a large piece of plywood or cardboard.

The idea is to keep tools and materials in one place while you work, because sometimes in all the excitement of building something, tools and materials can seem to walk away.

Collect all the materials you’ll need for the project and organize them in the staging area.

For the wood box we’ll be building, you’ll need the following:

  • 4 boards, 3 feet long x 6 inches wide (should be I or 2 inches thick)
  • 4 pieces of lath, 3 feet long
  • A writing utensil like a construction pencil
  • Cordless drill and bits
  • 12 deck screws
  • I roll of landscape fabric (see if you can buy a piece just 3 feet long at a garden center, or a pre-fab SFG box kit usually comes with the weed fabric and grid)

How To Build Your Own Square Foot Gardening Box Step By Step Instructions

The actual building of the box is simple once you’ve collected all the proper tools and materials.

  1. Stack the four boards, one on top of the other.
    1. Hold one board perpendicular, on its edge, at the end of the stack. This board is used to mark the overlap width.
    2. Mark the width of the board along the ends of each of the other boards.
  2. With the boards stacked up and aligned, pull each one out in order and drill three pilot holes for screws, spaced evenly from edge to edge.
    1. If you are using 1x wood stock [actual thickness is 3/4 inch, draw a reference line 3/8 inch from the end of the board to help align your screw holes.
    2. For 2x stock [actual thickness 1 1/2 inch] draw the center reference lines 3/4 inch in from the ends.
  3. Drill three or four pilot holes at each corner. For standard deck screws, use a drill bit that’s about 1/16 diameter.
  4. Hold or clamp the boards together, overlapping each successive corner. Drive deck screws into the predrilled holes until the screw heads are just slightly below the surface of the wood.

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