May is the perfect time to start your urban vegetable garden, or even build one. For several years now, I’ve been lucky enough to have an open-ground vegetable garden where I can grow a wide variety of vegetables. Even so, I lived in apartment blocks for a long time, and container gardening was my best friend. I grew both in good old rubbermaid tubs and in all sorts of recycled containers. It’s always surprising how many varieties you can grow above ground, and quite easily.
When I joined the Urbainculteurs team, I rediscovered the pleasure of greening concrete and small spaces, while maximizing the use of useful and edible crops with raised wooden vegetable gardens. What a pleasure it is to beautify places with these unique urban furnishings! Here are a few tips and tricks to help you create garden furnishings that’s as aesthetically pleasing as it is affordable and durable!
What Type of Wood Should I Use?
Many are available on the market. So it’s important to make an informed choice if you want your planters to last a long time. You may have to invest a little more at the outset, but this investment will quickly pay for itself with all the tasty vegetables you’ll enjoy afterwards.
Brown Treated Wood
This type of wood has been treated with alkaline copper quaternary. It is recommended for building structures such as pergolas, patios and benches. Although very durable and tempting to use for garden planters, it is not yet recommended by Health Canada for contact with food.
Spruce and White Pine
Easily available in many sizes, these species have little natural outdoor resistance if left untreated. Spruce is more affordable, but less attractive than pine. White pine, on the other hand, is lighter – an advantage if you need to move your planters!
Hemlock and Larch
Both species are naturally resistant to outdoor use. Less readily available, planks will tend to warp and crack with age. For its aesthetic appeal, larch is an interesting option.
Cedar
A big winner for its high natural resistance to outdoor use, it is aesthetically pleasing, lightweight and available in several sizes. There are two types of cedar on the market. Eastern white cedar (Thuya occidentalis) is our #1. We use it at Urbainculteurs for all our urban vegetable garden furniture. It’s local and affordable, though a little less accessible than Western red cedar (Thuja plicata), which is more expensive, less local, but available at many hardware stores.
Materials for Assembly
Screws, nails and other materials are a dime a dozen in hardware stores, so it’s easy to get lost! Here’s what our team uses to make your project a success. Use exterior-treated screws and a good food-grade wood glue. For more structural parts, such as joists (the boards on which your tub floor rests and which will have to bear a great deal of weight), you should opt for galvanized steel structural screws.
Why choose this type of screw for your floors? Because standard screws are good for exerting pressure and gluing two boards together, but are less resistant to lateral and torsional forces, and more likely to break! If you want to cut costs and avoid buying structural screws, which can be expensive, and if it’s not a structure that poses a danger, you can vary screws and nails of the right size (nails are stronger in torsion).
Wood Preservation
Although many types of wood are naturally resistant to outdoor use, I recommend that you carry out an appropriate treatment to prolong the life of the wood and make it more aesthetically pleasing. If, however, you don’t wish to carry out this work, be aware that your wood will turn gray and perhaps even black much more quickly.
There are different treatment methods: linseed oil (not very resistant to graying), the Shou-sugi-ban method (torrefied wood) and the application of a stain designed for wood. We use Sansin stain, a water- and linseed-oil-based product that is available in several shades, easy to apply and affordable. It’s important to sand well to open up the wood grain before application. Make sure there’s no rain in the forecast for at least 48 hours before and after application, and that it’s 10°C (50°F) both day and night.
Finally, the inside of the tubs is preferably covered with felted geotextile. Don’t use any plastic sheeting, as we want good aeration and drainage; it has to breathe!
Some Useful Garden Pieces
In closing, I’d like to present a few interesting pieces to build for your urban vegetable garden. Whether you’re a woodworker or not, I hope this brief incursion has inspired you for your future container gardening projects. And now, to your hammers!
The Garden Container
- Bin depth: minimum 12″, ideally 20″
- Not too wide, not too big (ergonomics and mobility)
- Allow for the weight of wet soil/compost on the floor/joists
- Geotextile inside
- Floor spacing (water drainage)
The Growing Bed
- Level the ground before installation
- Minimum 10″ height
- Not too wide and not too long (ergonomics)
- Wider boards: 2″ or more for edges
- Geotextile on walls only
- Cardboard or newspaper at the bottom: this will degrade and leave your potting soil in contact with the existing soil.
- Horizontal reinforcements every 4 to 6 feet
The Compost Bin
- Galvanized wire mesh interior with 1/4″ or 1/2″ mesh openings
- Space between boards for ventilation
- Lid with hinges
- Front panel can be removed in 2 sections (for easy brewing)
- Not too high and not too big (ergonomics), but not too small either (heat and microbial life).
- Cardboard and mesh bottom (rodent-proof)
A few years ago we built our raised-bed garden from cement block. It’s not attractive, but it’s functional. Our garden is tucked between our house and garage and not very well seen from the street anyway, so there’s no loss of curb appeal there.
I’ve been using galvanized livestock tanks in southeast AK for 3 summers. My wood raised beds were low to the ground and rotted in 7-8 years. No going back, these tanks are at my level with very little bending. Yes, initially expensive, but they are going to outlast any wooden beds.