Raised vegetable garden beds are raised above ground level with some sort of frame. Common materials for the frame are wood, bricks, corrugated iron, stone and concrete. This sort of garden bed is ideal for back-yards and other gardens that are tended by hand, but probably inappropriate for 1000 acre farms that are tended by large farm machinery.
There are many reasons for using raised garden beds here are the main ones for me.
The very first veggie garden I remember starting was when I was 8 years old. There was a semicircular mound at one edge of the garden, and I begged my father to be allowed to use it as a veggie garden. Eventually he gave in.
The first step of course was to dig up the grass, which I started with enthusiasm. But I found that the job was long and hard. I ran out of enthusiasm long before the job was completed, unfortunately the disinterest continued long past the digging process. In the end someone else finished the digging for me; the final result was a semi-circular garden that was no longer a mound. I kept my disappointment about this aspect to myself, but I am sure it added to my disenchantment with the whole process of gardening.
More recently I had an elderly neighbour who was an expert gardener. Despite being disabled he managed to till his vegetable plots to a fine, even texture, like sifted flour. I don’t even know how to do that, let alone have that kind of stamina. So when I heard about no-dig gardening I realised this was the method for me.
Raised vegetable garden beds are the ideal situation for no-dig gardening. You simply build or place a frame on the ground and fill it with a suitable growing medium, and your garden is ready to grow.
Scientific reasons for Raised Vegetable Garden Beds.
Digging damages soil structure. Soil structure is the arrangement of the soil particles and the spaces between them. Naturally soil form layers with more organic material at the top, and firmer rock based elements, like sand and clay, in the subsoil. The spaces between the soil particles are created by worms and other creatures that live in the soil and they allow for water and oxygen to be available to the plants, as well as room for root growth. Digging and tilling destroy the layers and the worm tunnels.
Raised garden beds can be warmer than vegetable plots in the ground. If the frame is constructed from material that absorbs heat, such as metal or bricks, they will absorb extra warm from the sun warming the soil more quickly. If the frame is made of insulating materials such as wood, it will help the soil retain heat over-night instead of losing it to the neighbouring ground.
Australian soil quality is very low, and here in the Blue Mountains top soil very thin, previous gardens I’ve had here had no more than 3mm (1/8 inch) of top soil. Not enough for veggies! Raised beds are filled with a rich growing medium, ideal for the high demands of food production. The bed walls also ensure that precious compost and soil is retained within the garden bed itself and not spread across paths and other areas.
Raised beds allow for a clear distinction of paths from bed areas. Walking on gardens can compact the soil and so inhibit the growth of plants. By surrounding small raised beds with designated paths there is no temptation to walk of the growing areas.
Raised Garden Beds provide easy access
Finally raised garden beds make it easier to reach the plants. Less bending down for access means less damage to the gardener’s back and knees. Garden beds can be raised high enough for access to people in a wheel chair, although I don’t need this provision.
My Raised Vegetable Garden Beds
My intention is to try beds of different heights to compare the outcome and find the optimal depth for this location. I will also try different structural components and different growing mediums. It won’t be a fully controlled comparison, but I hope to have some results that give enough information to improve the production of my raised vegetable garden beds next year.