WHAT TO GROW IN AND WHERE - Vegetable, Fruit and Herb Growing in Small Spaces - page 9

Now the big problem with beds at waist height is the pressure of soil causing the sides to
bulge and warp, especially when wet. You can use brick, but here you need either to be a
good bricklayer or to get one in. In effect you're building retaining walls and a good brick-
layer will know how to do this.
There is, however, a simple and economical way to build very deep beds. Buy the concrete
fence posts that have a groove to set the panels in and fix these firmly into concrete about
12 inches (30cm) deep so they will not move. There will be more pressure on the posts than
with a fence so it's important they are rock solid. This should leave enough post standing to
slot your boards into. Then slot in two of the concrete gravel boards designed to go under the
fence panels, one above the other. Some suppliers will provide the gravel boards at special
sizes or cut them down for you on request so you can build your bed to your requirements.
These concrete beds can look very clinical and unattractive. However, you can hide them
behind willow hurdles or paint the concrete with milk or milk with plain yogurt mixed in to
encourage the growth of lichens and age the concrete. Once the new edge is off they look a
lot better.
If you just fill your deep beds with soil or compost, then drainage will become a problem.
Over time the material will compact and can become waterlogged and sour. There is little
point in filling it anyway as most vegetables will be fine in 18 inches (45cm) or less of com-
post. There are a few exceptions, such as long carrots and parsnips, but as a rule 18 inches is
all you need.
Fill the first 18 inches with a mixture of rubble and gravel, breaking up the soil below if
it's a hard clay pan first. This will ensure easy draining. Top up above with your compost and
you're ready to go.
Trestle Bed
The 'fault' with waist-high beds for wheelchair users is that they're forced to work to the
side. If we can construct a bed like a table where the chair can go under, then it's possible to
work face on.
Now the problems here are two fold, depth and weight. If the bed is too deep, then it will
be really awkward to use but, luckily, many vegetable crops will be perfectly happy in just 6
inches (15cm) of compost so long as there are plenty of nutrients present.
Don't under-estimate the weight of the soil. Incidentally, this applies to the waist-high beds
and any container growing. The exact weight will depend on the moisture content and com-
position of the soil/compost mixture. A bed 6 inches (15cm) deep, 6 feet x 3 feet (2m x 1m)
will contain 10.5 cubic feet (0.3 cubic metres) which is the same as four 75 litre bags of
multi-purpose compost. If there is sand in the mix, which is a higher density than compost,
the weight will be much greater and then we have the water content to consider. The water
fills the gaps between the particles so we could be looking at around 176 pints (100 litres) or