In permaculture design, we are always looking for natural ways to solve problems. So, for instance, if we detect a lack of nitrogen in the soil, we might consider planting a leguminous crop to help fix higher levels of the element in the soil. Or if we notice that deer have been nibbling the vegetable patch, we might plan to plant a thorny shrub to act as a barrier.
Another potential problem that can affect permaculture gardens is overpopulation of insect pests. These are insects that, if allowed to breed in too great a number, can negatively impact the success of crops and the populations of other organisms.
Naturally, as a permaculture gardener, we do not want to tackle this situation with expensive, damaging inorganic pesticides, whose effects can be much more far-reaching than we initially consider – such as killing unintended species, becoming part of the food chain, and leaching into the soil and from there the water table. Rather, we look to nature for a solution and design our site to maximize the effectiveness of nature’s answers. Here are some of the ways permaculture designers can harness nature to manage pest populations.
Arguably the simplest method of preventing attacks on your plants by insects is to plant species native to your location. Choosing trees, shrubs, bushes and plants that are adapted to thrive in the local soil and climatic conditions means that they have evolved to cope with the indigenous insect life. Indeed, over time the plants and the insect populations are likely to have built up symbiotic relationships and, if undisturbed by human activity, would naturally find appropriate levels of all species so that all have viable populations. And by being adapted to the weather and soil conditions in your location, natives will be the most likely species to grow strong and healthy, making them much more adept at fighting off disease and insect attack.
The principle of maximizing biodiversity that lies at the heart of permaculture design is also useful in limiting crop loss to insects. One of the reasons that monoculture agriculture uses so many chemical pesticides is that a single population boom of one insect species can spell disaster for the whole crop. In a permaculture garden with lots of different species, even if one crop does suffer from an over-exposure to an insect population, there are lots of others that will not be susceptible to the same fate.
Furthermore, by planting a diverse range of species you are likely to attract a greater variety of insects to your plot. Some species will predate on others to ensure healthy numbers of both. You can also site plant species near one another than will ward off insect attack, either by confusing the insects via the shape and colour of their flowers and leaves, or through conflicting scents. The mutual benefits of certain species in pest management are one of the things to consider when planning plant guilds.
Different Harvest Times
A tactic linked to biodiversity, is to design your site with crops that have differing harvest times. By staggering the times throughout the year when crops ripen, you not only ensure a supply of fruit and vegetables for your kitchen for longer than a single growing season, you avoid exposure to an insect population bloom decimating your entire harvest. There might be natives that help you achieve staggered harvest times on your plot, but you can also utilize microclimates ad greenhouses as well.
The animals you choose to keep on your permaculture plot are useful in controlling insect populations. Chickens have a very wide diet and will eat most insects, which they come across. With the habit of scratching and turning over leaf litter and soil, they are also effective at controlling soil-based pests and eating insect eggs. Ducks also eat insects and have a taste for slugs and snails, which can be useful if populations grow and attack your vegetables. If you keep larger livestock, such as pigs, these creatures are beneficial in pest management on larger scale plots. For example, pigs will forage fallen fruit if allowed to range in an orchard, eating not only the fruit but also the eggs and larvae of insects which breed in it.
Habitat for Wildlife
When it comes to the animal kingdom, it is not just your livestock that can help in controlling pest populations. Insectivorous wildlife will arguably have an even greater effect, if your provide conditions which will attract them to your site. For instance, if your permaculture design incorporates plenty of tree canopy for protection from predators and the elements, as well as nesting sites, you are likely to attract birds to your plot, many of whom have predominantly insect-based diets. Every type from wrens and woodpeckers to sparrows and swallows will help keep insect populations in check. And, in another example of nature finding the right balance, they birds will eat more insects in the spring and summer, as they raise their young – exactly the seasons when insect populations are liable to be at their most abundant.
And it’s not just birds that will keep insect numbers in check. Creating a pond on your site will attract frogs, while undergrowth and shrubs will attract insectivorous mammals like hedgehogs and shrews, as well as spiders.
Nature will always respond to the conditions. It is highly adaptable in that way. So, if you decide to fertilize heavily and your plant growth enjoys a rapid spurt, nature will respond to this abundance and produce more insects to take advantage. As such, you want to aim to provide a constant, but not excessive, supply of nutrients to your plants. Mulching is a good technique, as it offers the slow-release of nutrients as the organic material breaks down over time.
Generally, a healthy garden, with a diverse range of species, will naturally find a balance with the insects that visit or inhabit it. Remember that your permaculture plot is an entire ecosystem that, run in accordance with nature, will adapt and change over time to retain that balance.