Raised vegetable garden beds have become very popular over time – possibly because gardens are getting smaller or simply for the convenience raised beds offer, as you don’t have to bend over to tend to them, or worry about the lawn or other plants encroaching into the veggie patch.
Raised beds can be extremely productive, but people often find that the yield reduces within three years due to the type of soil most people use in these beds. It is often a sandy loam which may be organically enriched, and although it’s great to dig and plant into, not only is the nutrient and water-holding capacity limited, but the biological activity of this type of soil is also limited, especially once the organic material has been used up by the plants.
In order to overcome this problem, you need to stimulate the biology in the soil and replenish lost nutrients on a regular basis. What occurs over time is that the nutrients get used up by the plants. We then harvest the fruits, herbs or vegetables, but often don’t think about replacing all of those nutrients that have been transferred into the harvest.
Raised beds are different to normal garden beds in that there is little or no nutrient transfer from the subsoil into the raised bed – earthworms just don’t go deep enough to bring up the nutrients. Additionally, there is no way for nutrients to diffuse from the surrounding soil into areas of low nutrient level. On top of this, these beds tend to dry out and become nutrient deficient, so soil microbial diversity drops.
The best way to rejuvenate your raised veggie beds is to add some well-composted material, which will feed the soil microbes, and then supplement this with a pelletised fertiliser such as Neutrog’s Gyganic for Veggies, Fruit & Citrus. Digging in compost should be done at least annually, but feeding with Gyganic should be done every 8 to 10 weeks between plantings. A monthly dose of GOGO Juice is a great way to rejuvenate the soil microbiology and help the organic matter to break down.
Following this practice will help you achieve a sustainable raised garden bed where the soil is nutrient-rich, will retain water and be productive for many years.
Gyganic and GOGO Juice are available from Bunnings, other hardware outlets and of course good garden centres.