An excellent way to grow vegetables is in a garden bed with raised borders, usually called raised garden beds. This page looks at both the advantages and disadvantages of raised vegetable beds.
RAISED VEGETABLE BEDS - ADVANTAGES
LESS WATER RUNOFF
Ground vegetable beds will inevitably form sloped mounds as they are turned and manure is added. When these mounds are watered or it rains, a proportion of that water will run off the sides of the beds and onto the paths in-between them. Whereas the soil in raised beds features a flat surface, with the top edges of the raised beds forming a natural barrier. This combination insures that almost all the water applied to the raised beds will end up in the beds and not on the paths.
BETTER DRAINAGE
Raised beds have better drainage than the ground below, this is especially so if the ground is low lying or of a heavy clay base.
WARMER SOIL
As the warmth of the sun’s rays is absorbed both on the top and through the sides of raised beds, they tend to have warmer soil than vegetable beds at ground level. The advantage of this is that in the winter, plants can still grow and in the summer, heat-loving plants (such as eggplant and capsicum) will flourish.
Back-Friendly
Raised beds mean that you do not have to bend down as far to tend to your vegetables. The higher the raised beds, the less bending. Higher raised beds (17 to 32 feet tall) will make gardening much easier for the elderly or people with bad backs.
RAISED VEGETABLE BEDS - DISADVANTAGES
MORE COSTLYRaised beds are more costly than ground vegetable beds. Today there are a range of premade raised beds that are easy to set up and can look very stylish. However, good quality, premade raised beds are expensive. You can make your own raised beds for less but the materials are still expensive and requires time to make them.
HIGHER EVAPORATION RATES
Warmer soil increases the evaporation rate. As raised beds are warmer than ground beds, the evaporation rate is higher. The higher the bed, the higher the evaporation rate. If the sides of your raised beds are made of wood, evaporation will also occur through the wood, especially if the wood is softwood. As the sun’s rays dry the timber, moisture is drawn from the soil through the timber in an osmotic process. If you have wooden raised beds that are higher than 20 cm, then it is a good idea to line the insides with builder’s plastic to prevent this from happening.
