The organic garden at RVA is based on Permaculture principles, which view the garden as an ecosystem, and applies a holistic systems approach to fertilization and pest control.
Plants are positioned on a garden bed according to their respective plant families. In this way, by mixing plant families, the fertilizer requirements of the diverse plant families are more easily met by the soil than when growing a mono crop.
The soil at RVA organic garden is sandy and in order to grow organic vegetables, fruits and herbs it is necessary that the topsoil have a structure that enables retention of water and nutrients as well as providing a cool and protected home for our all important microbes. To this end we have experimented with the burying of coarse organic material under garden beds as well as the mixing of soft rotted wood with horse manure and bio-char. This mixture is then applied to the tops of the garden beds and mulched.
The mulch, itself in time becomes fertilizer, as it is transformed by the soil microbes into rich humus. Mulch and composting materials are grown in and around the garden in the form of support species. These include trees and vining beans that are capable of fixing nitrogen from the atmosphere, the organic matter deriving from such species are noted for their high nitrogen content. Therefore when these species are pruned their cuttings provide the soil or the compost with additional nitrogen whilst also releasing nitrogen from the nodules on their roots into the surrounding soil to the benefit of other plants.
The main source of fertility for the RVA organic garden is our compost production. This is based on the mixing of nitrogenous (green) organic matter such as kitchen wastes and horse manure with carbon based (brown) organic matter such as dried plant material and cardboard. This combination provides the diet required by soil microbes to rapidly decompose the cycled organic matter resulting in high quality compost providing excellent fertilizer for hungry fruits and vegetables.
In addition to the above methods of soil regeneration the students at RVA with responsibility areas for the garden experiment with liquid fertilizers, most commonly in the form of; compost tea, nettle tea, moringa tea and the liquid effluent from the biogas digester. These are applied either as a foliar spray or to the root of the plant.
A Permaculture garden is an array of colour, shape and form offering a diversity of plant families and species, some specifically planted to attract beneficial insects whilst others have been planted to repel pests. Due to this design the garden suffers minimal damage by pests. When an outbreak does occur we experiment with various organic solutions to pest control including using neem, garlic, hot pepper and bacillus thuringus (Bt)which are typically applied as a liquid spray.
Here is how to make Moringa Fertilizer