A 24 square ft garden like this can grow a remarkable amount of food and is easy to build and take care of.
Once you have all of the materials gathered up you really can set up a square ft garden like this in about an hour. As you probably already know “Square Foot Gardening” is a method promoted by Mel Bartholomew. Basically you grow in a permanent raised bed full of highly enriched soil which is divided into blocks which are 1 foot square – each block is intensively managed and cultivated. It is an especially effective method for small areas and people who are new to gardening – there is no need whatsoever for roto-tillers or any other expensive equipment.
The bed in this article does not yet have a square foot grid so according to Mr. Bartholomew it isn’t quite a square ft garden. I guess that will be up to the owner (My Daughter Sharon) who has been reading the book. Anyway here are the simple steps to building a Square Foot Garden.
The frame for this bed is made out of regular SPF grade construction studs – not pressure treated – and should last 3-5 years before it rots and has to be replaced. In my opinion treated lumber should not be used to construct garden beds, because of the chance that it will leach nastiness into the soil which could either harm your plants or end up in your food.
For this project we used:
- 6 – 2 x 4 x 92 5/8″ studs
- 4 wooden stakes about 14″ long (made out of scraps of 1 x2)
- 16 – 3 1/2″ screws
- 10 – 1 1/2″ screws
- Some newspapers
- 2.8 cubic foot bale of peat moss
- 2.8 cubic foot bag of vermiculite
- 40 gallons of screened yard compost
- about 5 pounds of rabbit poo
Start out by cutting two of your studs up into 36″ pieces, and then screw them together – Put the 36″ end pieces between the long side boards so that the inside width of the bed is 36″ . You could go all OCD here and carefully measure, mark, pre-drill, and counter-sink each hole if you like, but consider 2 things first:
- You ain’t buildin’ a piano.
- It will rot it a few short years.
So, do whatever makes you happy.
Once you’ve put all of the boards together so that you have two rectangular frames, stack them on top of each other and screw them together. You can make this easier and neater by first drilling a 3/8″ (more or less – it isn’t critical) hole about 1/4″ deep at all of the locations where you want to angle screw the two frames together.
Then drive screws downward at an angle through the side of the holes you drilled in the previous step. This is an improvised pocket screw – it’s just as fast and strong as a “real” pocket screw, but without the expensive pocket jig. It also looks almost as good if you’re careful. I used about 10 of these to hold the 2 frames together.
Once you have the frame completely assembled place it where you want the finished garden to be – pick a place that is in full sun, near the kitchen, and also near a water supply if at all possible. A level spot with good soil would be awesome but not really essential.
The spot for this bed had lots of grass growing on it so I used a weedeater to cut it as short as possible – I suppose you could skip this step if you wanted. Now drive a wooden stake in each corner. Since our spot isn’t level I leveled the bed by raising the frame and screwing it to the stakes. If your site is level you can skip this step.
I filled the worst of the gaps between the frame and the ground by screwing scraps of chip board to the inside of the frame. The gap can be dammed up from the outside with soil, grass clippings, or mulch once the bed is finished.
Once the frame is leveled and secured to your satisfaction cover the bottom with several layers (at least 3-4) of newspaper or cardboard, Then wet it down so that it mats down good. Lap the newspaper up the sides a bit. The newspaper will help to kill the grass and keep it from growing up through the bed, but will very quickly decompose.
Now start adding the soil mix. If you choose to mix it in the bed like we did don’t just dump all of the materials in a lump – spread them out in layers and it will make it much easier to mix. By the way, I can’t think of a single reason not to mix in the actual bed and several reasons why you should. Anyway, we started with a layer of compost…
Spread that out, then add half of the peat moss…
Half of the vermiculite…
and so forth until you use up all of the soil ingredients.
Now simply use a hoe or tilling fork to mix it all thoroughly together – with just a little care it isn’t hard to avoid tearing up the newspaper.
When you’re finished give it all a good watering and wait a day or two before setting out any plants to allow all of the ingredients to absorb the water. If you have seeds you want to sow there is no reason not to go ahead and do that immediately.
Needless to say you could use different materials and build the bed a different size. I like 3 foot wide beds because you can reach all the way across without running laps around the bed – the length of the bed is as much a product of the previously used materials that were available as anything. If I had 10 or 12 foot materials I would probably build beds that size unless there is some compelling reason not to. Of course you could also build a bed that is only 2′ x 2′ if you want, but at some point you might just want to get a big flower pot.
Even so, the 3′ x 8′ size that we did use is pretty handy because one bag each of vermiculite and peat moss worked out well to fill it – along with our home made compost. It would also be easy to construct a cold frame or poly tunnel to cover a bed this size.
Of course you could use any number of materials to formulate your soil mix – which is essentially home made potting soil.
So, you’re just a simple afternoon project away from being a square foot gardener. If you haven’t already tried it, you should .
Happy gardening.
For starters: madly in love with your website.
For seconders: I’m about to start my own SFG, and I’m wondering why you went for 12 inches deep instead of 6 inches.
Actually the depth of the frame is 7″ because it’s made out of two layers of 2×4 (nominal) lumber which is 3 1/2″ wide each. All lumber in the U.S. is smaller than the name would suggest.
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This is largely a case of using what I had already. 3 1/2″ would be too shallow thus the stacking of layers.
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Anyway, deeper is better. Any raised bed is essentially a big container which (because of the open bottom) allows the plants to forage into the underlying soil for additional moisture and nutrients, but most of the action takes place in the top layer of improved soil.
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A shallower bed has to be watered and fertilized more often – so it suffers more from the ups and downs of moisture and fertility.
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You probably know that this also applies to regular containers as well – the bigger they are, the easier they are to take care of.
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And, thanks for the comment, and the compliment.
I also love your site and have found it so useful for so many of my garden projects. I just had one question for you and it has to do with using vermiculite vs. perlite. We went with perlite in our raised beds after reading that vermiculite could contain asbestos in it. I don’t know much, if anything, about either substance, so I’d like to hear other opinions. Thanks!
The choice of vermiculite instead of perlite was because it was available in bulk locally and at a reasonable price while perlite is not.
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It’s true Lacey – in the past vermiculite has been known to contain asbestos and resulted in class action lawsuits involving millions of dollars. Apparently that material all came from a few mines which were contaminated. Supposedly all of the vermiculite on the market today comes from safe sources which are asbestos free. I’m not vouching for the safety of vermiculite, and ideally I wouldn’t use any store bought, corporately produced products at all.
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Everything is a calculated risk – honestly I don’t know that the results wouldn’t be comparable by just using sand. Sand is much heavier, but is inert, safe and very cheap – maybe free.
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You make a good point and a very reasonable concern. Thanks for the comment.
Thank you! You went to a lot of trouble for our benefit. I hear a lot of stories about Vermiculite whats your view?
Not so much trouble really. Since I was helping my daughter all I had to do was take the pictures (or get her to)then edit, and upload them and write the article. Practically nothing. But thanks anyway.
About Vermiculite – read the comment below by Lacey and my reply.