How to build 4×4 square foot garden boxes with a wood bottom.
What you need: Our cost for new wood and materials was about $25 per box with materials purchased from Home Depot. You can also build them for free if you can find the wood in excess. Right after we built ours with new wood, we were driving down a road and in a yard, they had a big pile of “free” wood that would have been perfect! However, $25 is not bad for new and you know where the wood has been and if it was treated or not.
- Non-pressure treated wood, 2×6’s or 2×8’s (depending on the depth you want), 16 feet per box, cut in 4 equal foot lengths (cut by lumber yard or at home).
- 12 3-inch deck screws
- 32 1.5-2 inch screws (depending on the plywood thickness you choose)
- Power Drill with Screwdriver head bit
- 4×4 slat of untreated exterior grade plywood that is 5/8 or 3/4 thickness
- 6 4-foot long lath (the thin wood to create your grid on top)
To build:
- Start by drilling 3 holes at the end of each of the 2×6 boards.
By the way, in the far left corner of this picture, you can see a pile of wood, we did recycle free wood for a compost bin!
- On a flat surface, lay the beams out with the drilled ends touching the end of the next beam until you have a square.
- Drill your deck screws in the pre-drilled holes into the end of the next beam and go all the way around until you have completed the square.
- Add your plywood bottom. Set the plywood on top and, using your smaller screws than the deck ones, simply screw the bottom to the beams by screwing down 6-8 screws on each side.
- Finally, drill a drainage hole in each square foot on the bottom of your plywood. Plus, Mel (the Square foot guy) also suggests adding an additional drainage hole in each corner.
Finished boxes!
We wanted 4 total boxes so we made another one after this picture for last year.
This year, we will be adding 2 more for 6 total!
When you are ready to plant, you will want to lay down your lath as your grid. Some fill their boxes with the dirt first (like Mel’s mix) and then lay the lath, or you can do the lath and then fill with dirt. It’s your choice! The first year, we laid the lath after we filled the boxes with dirt.
- Simply measure and lay the lath 12 inches apart and lay across your board.
- Once they are in place, just nail the lath into place onto the wood beams.
- Follow these steps for the next side until you have a grid of 16 1-foot squares.
That’s it!
Here’s pictures of our finished project (from last year – they are empty right now, but hopefully won’t be in a few weeks :))
Here’s more gardening articles to help give ideas:
– Our 2014 garden plan and free garden planning downloads HERE
– Our 2014 indoor seedlings growing right now HERE
– Many more gardening tips in the garden section of our site HERE
Delana
Plywood on the bottom is not only unnecessary but a potential soil threat. I would be very concerned that the glue used in the making of plywood would leach into the soil. A weed barrier type landscaping fabric would be a much better choice. We have used it for years with zero weed problems.
Karen
Glue: urea formaldehyde and phenol formaldehyde
Would not want to eat. If you need to brace it so that it remains square, just use corner braces.
Kim Roman
Hi Guys!
I’m a Square Foot Gardening Certified Instructor and assistant to Mel Bartholomew. One of the other people pointed out that if you’re putting the raised bed on the ground it doesn’t absolutely need a bottom, but you certainly can use one. I would probably raise it up on little blocks of wood (or bricks) so that it can drain better.
For those concerned about chemicals . . . you can also use window screening as a bottom (of course cross braces on the bottom would be needed. In this case you would want to add a layer of landscape fabric (weed cloth) on top of the screen to keep your Mel’s Mix growing medium in the box.
BTW 2016 is the 40th Anniversary of when Mel Bartholomew introduced the SFG method to celebrate America’s Bicentennial.