Building our first Square Foot Garden Boxes


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Building our Square Foot Garden boxesWell, we built our first Square Foot Garden boxes today and I must say that it was a little bit more involved than I thought it would be. Not to worry though, now that I’ve done it and ironed out most of the ‘kinks’ for you (and for myself for the next batch of boxes) it should be a walk in the park for anyone taking notes πŸ˜‰

First of all, I was in a bit of a hurry to get things up and running and although I have had a few offers of some odd scraps of wood to try and hammer together a reasonable box or two, this would have meant a few compromises on what I wanted my first (display) boxes to look like. It’s a lot more work trying to fit together odd shapes and sizes of planks and beams to make a decent looking box. I would also have had to ‘clean’ the wood a little first. If all I wanted was functionality then I wouldn’t care what the boxes looked like, only whether they worked or not but I know that there are many eyes on us at the moment… including yours πŸ™‚ , so I’m prepared to spend a little extra this time around.

So in the end I decided to spend the money and off we went to Builders Warehouse to see what wood was cheapest and most commonly available. There were so many options/lengths of wood at varing pricing points that I had to take notes and then come back home to work out all the various cutting options and calculate final prices. I finally went with 2.4m x 455mm x 20mm Pine boards and had them cut the boards in half width wise to make 200mm x 20mm planks. Then I had them cut the planks to my required lengths. The ‘excess’ wood from each plank I kept to make extra odds & ends for the Square Foot Garden (things like a frame for a shade cloth cover on one of the boxes).

My cutting plan is as below:
Square Foot Garden Box - Wood cutting plan
Buying four of these pine planks @ R224.99 each was not cheap but as I’ve mentioned, I was in a bit of a hurry πŸ˜‰

Putting the boxes together is then quick and easy as there is no cutting involved. Simply drill three holes through one end of each plank and then screw the corners together using 40mm wood screws (the length of the screws should be at least double the thickness of the wood that you are using). You should try and rotate the corners on your boxes instead of having two ‘outer’ sides and two ‘inner’ sides. If you ‘rotate’ the corners then you don’t have to take the width of the wood into account when creating your cutting measurements for a square box.

We decided that the boxes would be semi-permanent fixtures in our garden and as such there was no need for plywood bottoms. We simply flattened a few cardboard boxes and placed them in the bottom of the boxes covered with newspaper and well watered with a hosepipe to form a ‘weed barrier’ and also to prevent anything else growing and/or crawling up through the garden soil into our boxes.

The grids were made with 44mm x 10mm pine slats which were easy to cut to size myself and screw onto the top of the boxes. I see many people using nylon string/rope to make their grids but I have this strange reluctance to use any sort of string for anything at all (I prefer using baling wire or duct tape for anything that needs fastening – probably a psychological scar from my early Landrover days ;-))

Below are some photo’s of our first Square Foot Garden box (click on the images to enlarge):

I hope to experiment a bit closer to the end of winter with more box sizes, shapes and materials and I will start a “Downloadable Box Plan” section on this blog at that time. These box plans will include detailed cutting measurements and plans, material shopping lists, local prices as well as alternatives to use should you not be able to get any of the materials in your area. I want to make it as easy as possible for you to simply select a box size and shape and get started straight away.

If there is anything else that you would like to know about building a Square Foot Garden box (also read our ‘Boxes & Covers‘ category for more info), please leave a comment below this post and I will either answer it here or write a new post to cover the topic in more depth.

Happy gardening

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6 Comments on “Building our first Square Foot Garden Boxes”

  1. Venessa says:

    Hi there,
    thanks for that – makes my life a lot easier!
    It seems you also started your SFG close to winter, what vegetables do you suggest i plant? i’m in JHB and i’ll be ready to start planting mid March.
    Also do you sell the Mels Mix premade?

    • Mark says:

      Hi Venessa
      Glad we could help. We made quite a few mistakes during our first winter season, hopefully we’ve learnt from them and this season will be a bit better.

      The winter season veggie crops are the Brassica’s – cabbages, cauliflowers, broccoli, kale, kohlrabi, rape, spinach and chard etc – and other leafy plants like your lettuces, rocket, mustard greens etc. Also remember to plant broad beans and carrots.

      We are starting our winter plantings right now, simply to give the brassicas the last month or two of warm weather and to give them a boost in their early stages. When the cold weather arrives, all growth slows down rather drastically and we want to give our winter crops a good head start, otherwise we will only be harvesting them next spring.

      Sorry, at the moment we don’t sell the premade Mel’s Mix but it is in the plans for the near future. Check out our new shop at for more info (please be patient though, we’re still adding products and building the resources section).

  2. Tyrone says:

    What did you use to prevent the pine from rotting? Won’t last long without some sort of sealant.

    Seeing the price of pots (even plastic), I’m building some square pots with scrap wood/ pallets I’ve collected. Want them to last a few years.


    • Mark says:

      We did’t use anything on our boxes, just plain untreated pine. We are banking on a lifespan of around 3 years for 38mm thick untreated pine planks – We’ll let you know in a year or two how that worked out πŸ˜‰

      You can use Linseed oil for an organic treatment to extend the lifespan of the wood, anything else is going to leach chemicals into your soil which will be taken up by the plants. Also be careful of using pallet wood as they are generally chemically treated.

  3. Basheer says:

    Has anyone tried precast fencing?

    Perhaps if you use 4x corner posts (use angle grinder to cut to required length) and go 1 slat high

    No rotting!


  4. Zikhona says:

    Hi there

    Thanks for this blog. I am new in veggie and herb gardening and I like the idea of SFG. My only limitation is that I live in a flat and I’d like to know if there is a way of making these boxes specifically for balconies – what should be used at the bottom. I would also like to know if I should make the Boxes deeper for root vegetables or vegetables with deep root system. I find pot planters of any kind expensive so I think this will be ideal for me. Also can you suggest a way of maximising my space – maybe a sort of ‘step’ boxes.
    Thank you!

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