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:
Plant!
