If you have a large-ish space, raised beds are the best way of being able to control the soil you plant in. They can be placed directly onto a concrete patio, or onto a lawn or bare earth (just be sure to lay down some cardboard at the bottom of the bed to kill off all weeds first, or you’ll get them poking up through the compost in no time).
In an ideal world, we’d all be building raised beds that look like this, but realistically, 4 planks of wood of equal width will work just as well. You probably want a minimum depth of 30cm to allow for good root development of your crops, unless you are only going to be planting lettuce, in which case you can get away with a depth of 15cm. But more about that in the Planting page in the Resources menu.
There are loads of ways to build a bed, but these three are the most straightforward. The easiest is to buy L- brackets from a DIY shop and nail or screw them in to the corners of your rectangle:
Another easy way, if you are using fairly thick planks of wood, is to nail directly into the sides of the planks like this:
A slightly more labour-intensive option is to cut some corner posts to the height of your bed, and insert these at each corner to nail on to. This will provide a sturdier bed, and has the benefit of allowing you build up height using several thinner planks of wood.
I’ve found skips to be the best source of discarded wood. Surprisingly often, you can find planks of wood of equal height and width which require no trimming down, because people have been ripping up floorboards or taking out shelves. But you may also want to buy recycled wood if you haven’t got the time to scavenge! If you live in London, the Leaside Wood Recycling Project is a fantastic source of cheap-ish recycled wood. The Riverwood Project may offer a similar service; although they’re really about creating unique pieces of furniture with members of the community with learning difficulties, they can also sell wood directly to the public. Finally, Bromley Community Wood Recycling can be contacted on 020 8778 9413. For a full list of organisations nationwide, see the National Community Wood Recycling Project‘s website. Remember that treated wood could pose a health risk if used for growing edibles, so avoid anything that looks like it’s had creosote or other chemicals applied. As a rough idea, treated and untreated wood look like this: