There is a great deal of trust put in ‘conventional’ horticultural methods, probably because they deliver a predictable result, and often in a short timescale. This is a vital advantage to any business that aims to pull a profit. Chemical pesticides are used often as a curative treatment, but they have a huge (negative) effect on the local biome – in many cases destroying entire populations of beneficial insects which would otherwise deter or actively hunt a wide range of potential pests. These ‘beneficials’ have a vital role in preventing outbreaks from even occurring by maintaining a lower population level of pest species. Without these friendly bugs, those potential pests turn into real pests, and over time the pest species gain resistance to the chemicals designed to kill them, while the friendly bugs being generally more sensitive to pesticide applications simply never return.
Perhaps the biggest difference with an eco-friendly integrated system compared to ‘conventional’ horticultural methods is the forward-looking approach involved in actively maintaining a rich and balanced biome. This ethos sits in contrast to the more reactive approach of the conventional methods, which tend to only deal with issues when they actually become a problem, or prescribes vast amounts of chemicals to be applied preventatively.
Our approach to tackling pests was therefore 90% preventative, and 10% curative – using predatory bugs as prevention, and natural horticultural soap sprays or other eco-friendly methods as the curative measures – when needed. After a few years we found that many of the ‘beneficials’ had happily established themselves as perennial occupants in the nursery and would spontaneously emerge when needed of their own accord in the spring. Regardless, we would still apply an annual refreshment of beneficial predators on a regular schedule each year to ensure pest problems rarely emerged. Our main helpers were Aphidius wasps, Californicus and Swirskii mites, Cucumeris mites, and occasionally other beneficials such as nematodes. When a pest infestation occurred it would sometimes be necessary to either pause sales of an affected variety until the beneficials ‘caught up’, or the pests would be sprayed with a horticultural soap and sometimes with specific plant oils such as Neem, Garlic, and others for a more potent and longer-lasting effect. Garlic oil was not our favorite to apply, as although effective it is pretty pungent and pernicious.
One of the earliest systems we employed was the production of plants grown in compost inoculated with mycorrhizal fungi and beneficial bacteria. These micro-organisms form an important part of the soil microbiome, and give plants an advantage in resisting drought and absorbing trace nutrients. The soil microbiome can also help to protect against some root diseases. Our growing media was sourced from local material, composted and blended to requirements under our own supervision. A major component was composted woodchip, derived from storm-damaged trees (often harvested from our own orchards), or trees which had to be replaced because they had become dangerous.
Water usage is a global issue, and although the nursery was located in a high-rainfall area where water was plentiful, it was precisely this feature that led us to design an irrigation system that made use of natural rainfall and filtered groundwater (springs) derived from natural rainfall. A great deal of rainwater was harvested and stored directly from one of the large barns (which was used as a packing facility), but a secondary system using a natural spring was also installed in case of long periods without rain. Much of the irrigation utilized simple gravity-based/siphon systems to move water to the various growing-areas, in combination with solar-powered water pumps. The stock beds were also designed to ensure that water had an opportunity to soak into the pots during and after watering, instead of simply running away as waste.
Our requirement for greenhouses was relatively modest – many of the plants were super hardy and required little or no winter protection. However, every nursery needs a sheltered environment for propagation and growing-on, and so we built a series of greenhouses using the most sustainable resources available – timber and polythene. While not without issues, both these materials are relatively easy to recycle at their end-of-life period, and overall had a more positive impact compared to the high energy input necessary for both glass and aluminium production (the two most common materials used for greenhouses). Having total control over the greenhouse design also ensured that we could make use of winter insulation methods, mini ground-source heating during the winter, and shading/ventilation during the summer.