Growing vegetables in raised beds, a technique developed centuries ago in Asia, is the perfect way to make small domestic plots productive. There are many tempting advantages; the soil warms earlier in spring, extending the growing season, they are easier to maintain as you don‘t have to bend to ground level, crops are sown closer together than in conventional beds yet production can be up to four times greater and the leaves create a canopy, smothering weeds. Perhaps the greatest advantage of all is no more digging! The plot is dug over when the beds are constructed, to break up the soil and remove perennial weeks, before compost is added to raise the beds, then never dug again. The secret is never to walk on it, so a good structure is formed. This and the fact that manure is concentrated only where it is needed makes the soil rich and fertile so roots can penetrate deeply, reaching water at lower levels, making them more drought resistant. Raised beds should be in a sheltered sunny spot and a maximum of 3m (10‘) long unless you can resist the temptation to step over the corners and wide enough, about one meter across, so you can reach the centre comfortably, without over stretching and should be tailor-made to suit.
The simplest raised beds are created from a flattened mound of soil, with sloping sides, like a segment from a bar of chocolate; digging out soil also creates the surrounding paths – it‘s simple, cheap and easy. The beds can be slightly angled too, rather than horizontal, a 5 degree slope is equivalent to moving 30 miles south and the sloping sides are perfect for a row or two of small, early crops like lettuce, radish or beetroot. Raised beds can also be enclosed in frames of pressure treated timber and secured with treated wooden fence posts; old scaffolding boards are a useful option, as they are about 9″ wide and are simply secured with posts at each corner with 2-3″ below ground. My hastily constructed beds are raised about 4″ above the ground and secured with site pegs from the builder‘s merchant but as I‘m gardening on clay with flints, I‘ve decided to raise them higher and recycle the 4″ timbers as edging for a raised bed for fruit bushes in one corner of the kitchen garden. It‘s a great job for September as there will still be time to sow autumn crops. They are being replaced with the help of my nephew, Simon, with a double tier of 9 x 2″ timbers screwed to vertical posts 3‘ long, all made of treated timber that will be painted to make them look more attractive. The main reason for the change is that it takes time to improve clay soil, so some of the advantages of raised beds are being lost; deeper beds, filled with compost either bought or home made, increases the soil quality instantly, but the bonus of easier and more comfortable working conditions is the greatest incentive for me and my poor back!
Happy gardening!
Matt