Building your own garden boxes

So, with a proliferation of “store” pre-made garden boxes with some assembly required maybe ist time to see how easily and cheap making one the old fashioned way is. I assume you have access to a drill and screws or hammer and nails. That really is all you need.

Step one:
Decide on your box size. Maximum size is four feet wide (length can be anything). Keep in mind that lumber comes in pre-determined lengths of 8 feet, 10 feet and 12 feet and you will want to make use of the whole board with as few cuts as possible. For example a 4×2 box would need an eight foot cut in half, and another eight foot cut into two 2 foot lengths with 4 feet left over. If you used a 12 foot board, you would cut 4 foot + 4 foot + 2 foot + 2 foot with no waste.

Cutting is easy – any lumber store will cut your wood to size for you – usually for free if its a small amount of cuts.

What lumber do you use?
Well the size of the lumber varies – they can be made of recycled wood, leftover wood, scraps, whatever you want. For this box lets just go with a nice sturdy 2×6 (2×8 or 2×10 are great too but more expensive). The actual type of wood is essential as most untreated wood will rot very quickly and will need replacement after only a year or two. Cedar is a natural rot resistant choice but is very expensive. My cedar boxes I built 5 years ago will likely need replacing next year.

Pressure treated boards are commonly available, rot resistant and recent long term studies have shown/proven that the typical pressure treatment does not have ANY affect on plant growth or food safety. (More info here)

So lets go with a pressure treated 2×6 in a 12 foot length. The lumber yard cuts your lengths for you – two 2 foot lengths and two 4 foot lengths. Now you got your box at a “some assembly required” stage. At my local home depot, a 2x6x12′ pressure treated board is $9. Maybe a dollar to cut it so $10 for the lumber. Probably should get some nails or screws – nails are easiest. 3″ screws or nails – nails should go for around $5 for enough nails for a dozen boxes. Spiral or ardox nails, galvanized will last forever, but they only need to outlast you box – which most nails will. Screws tend to be about $10/100.

You have four corners, each corner will need two nails = 8 nails total (a third per corner wont hurt.

So your ready to assemble kit is now ready for $20 and you supply the hammer, compare that to the cheapest pre-made box at $43 at my local Home depot.

Step two:
Two two foot sections go inside, hold them square and nail together (easier to start nails with the 4 foot section laying flat. Nails go through the four foot sections into the 2 foot sections, do all four corners – then you have a box.

Step three:
Lay paper, cardboard on ground (you could also dig it up a bit ) under where the box will go. Wet the cardboard. The paper/cardboard will slowly disintegrate, killing grass underneath it.

Step four:
Fill the box with compost/soil mixture. Soil should be mixed at a 1/4 peat moss, 1/2 compost and 1/4 vermiculite or soil of any kind. So for every bag of compost, you would add 1/2 of a similar sized bag of peat moss and 1/2 a similar sized bag of soil/vermiculite. THIS DOES NOT NEED BE EXACT! The key here is rich in compost. Bags of composted cow manure sell for around $3/bag, Peat moss around $10 for a large bag (multiple boxes) and soil for $3 per bag.

The 2×4 by 6″ deep bed here should take approximately 6 bags of compost, 3 bags of soil and the equivalent of three bags of peat moss (much larger bags). so with soil in your box you are up to about $45 all in per 2×4 box. Additional boxes will be slightly cheaper as you will have nails, peatmoss….

Step five:

Gardening Shortcut Links

Square Foot Gardening Section

What you will need

2×6 boards – pressure treated – you can get them pre-cut where you buy them

One 2×6 by 12 foot pressure treated boar will make one single 2×4 garden box.

Peat Moss
Screw Gun/Drill
3″ Deck Screws

Square Foot Gardening

Information and resources for square foot gardening here in NW Ontario.

Excel Garden Planner

An excel worksheet I developed to help plan and track my square foot gardening.


North Hardy Plants

Not all plants will grow here, but a lot will.


Garden Planning

North Hardy Plants

Tips and Tricks

Square Foot Gardening

About Garden Planning

Laying out your garden and pre-planning what to plant is best accomplished over the winter months. It gives you escape from the north winds, allows for ordering of seeds and allows you to put some time and effort into laying out your garden.

Since I use the square foot gardening method, I have created a garden planner using Microsoft excel. It allows you layout your garden using the cells in excel, then based on what plants you choose it will calculate planting/harvest times, potential yields, how many seeds you will need and more.

The Garden planner is provided as is, I can and will answer questions on using it and I have made videos on using it. I am hoping to have a full updated version ready for 2019 planning season.

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