How to Plant a Perennial Polyculture Food Forest Garden
Traditional Monocrop vs. Permaculture vs. Perennial Polyculture
There are three separate categories or types of gardening techniques. These techniques are traditional monocrop gardening, permaculture gardening, and perennial polyculture gardening.
A traditional monocrop garden is what most first world gardeners think of when they think of a garden, or even a farm; exclusive beds or expansive fields all containing a single crop, usually aligned in neat, long straight rows. These plantings are quite labor intensive to maintain, and require a lot of external intervention to keep the farm or garden producing. Pesticides are required to keep insects from eating all of the food, and weeding is required to keep out any and all plants except the one crop the land's caretaker intends to grow in the area. Fertilizer is also required, because a monocrop planting depletes the soil of certain nutrients, and once every three or four years the land must lie fallow, or at least the crops must be rotated so that the land has a chance to cleanse itself of the buildup of those particular nutrients which any given species of plant causes to accumulate in the soil. The traditional monocrop planting requires, of the three methods of food production this article will address, the most effort on the part of the land's caretaker per calorie of food produced.
Reader Experience Level with Perennial Polycultures
Which of the following best describes your experience level with perennial polyculture gardening?
A permaculture planting requires much less effort to maintain, as more than one species of plant are strategically planted in the same area in order to use the strengths of one species to cover for the weaknesses of another; allowing the plants to do much of the work for themselves and for each other that the land's caretaker would otherwise need to do in order to keep the garden producing. There are actually two main types of permaculture. One type of permaculture is still very rooted in the mentality of the traditional monocrop gardener, and may even contain a patchwork of strategically placed monocrop beds, which allows the plants to do very little of the work for themselves and each other. These gardens tend to focus on the production of annual crops, and must be replanted year after year.
The other type of permaculture is often referred to as perennial polyculture; because it incorporates and in fact focuses on, the planting of perennial trees, shrubs, bushes, ground covers, etc. The idea behind this type of planting is the creation of a self-sustaining designer ecosystem, artfully and strategically designed to produce an abundance of food all year round, and to be capable of maintaining and even perpetuating itself all on its own. The perennial polyculture is designed to be a forest full of food. One could consider it an attempt at a return to the Garden of Eden.
Basic Planting Strategy; The Layers of a Food Forest
There are seven basic layers of plant types which make up any forest, anywhere in the world. These types are categorized not by botanical or evolutionary relationships, but by the functions they contribute to the forest ecosystem, as recognized by Permaculture expert Geoff Lawton. These layers are;
1) Canopy Layer - The tallest trees in the forest, providing shade and protection from harsh elements for all other species.
2) Understory Tree Layer - These are the fruit trees and other relatively short-growing, flowering trees.
Pattern Layers of a Forest
3) Shrub Layer - These plants are not quite trees, but they are still woody plants. These provide habitat for small animals including birds, insects, small mammals and many other creatures who fill important roles of their own within the forest, including predation on pest species.
4) Herbaceous Layer - Small, nonwoody plants providing flowers, berries, medicines and other sustenance for all manner of creatures living in the forest. They also provide nutrients and medicines for other surrounding plants as well.
5) Ground Cover Layer - These small plants often spread by creeping across the ground where the soil has been disturbed, helping to keep the soil in place and reclaiming damaged ground.
6) Vertical Layer - These plants climb as vines on the other plants, filling vacant niches from ground to canopy within the forest.
7) Rhizosphere - Full of plants which grow from bulbs beneath the soil and provide edible bulbs and tubers during seasons in which food may otherwise be scarce. They also keep the soil rich with nutrients and alive with worms and other creatures who help to enrich and aerate the soil.
Each of these layers overlaps one another and all can be grown simultaneously in the same space, which is why both natural forests and designer forests can have such diversity of species coexisting and even cooperating for survival within a relatively small area.
Plants should be selected for utility as much as for desirability. For example, garlic or onions can be added to a garden troubled by insect pests to make the entire ecosystem more resistant to insects. Legumes may be added to a garden containing nutrient deficient soil, as legumes work with bacteria communities inhabiting their root systems in order to pull nitrogen directly from the air into the soil. This acts as a natural fertilizer. A garden which is experiencing heavy erosion from either wind or rain or any other antagonist can benefit from the planting of ground cover plants which creep across the surface of the soil and help to keep it in place; a garden which has trouble holding moisture in the soil will benefit from the same treatment - creeping ground cover plants act as a skin over the surface of the soil.
Many herbs will protect themselves and the plants around them from pests, fungal infection, bacterial infection, and so on. Many medicinal herbaceous plants will pass pest resistant capacities to their neighbors through root associations.
A garden experiencing downed trees due to wind sheer will benefit from the introduction of climbing plants in the vertical layer. The vines will grow from the ground sometimes as high as the canopy itself and create strong windbreaks from which all the plants in the surrounding landscape will benefit.
Tall trees in the canopy layer provide their shorter neighbors with protection from the sun and excessive evaporation. Fruit trees in the understory layer attract pollinators to the garden which will benefit all species of flowering plants and will enhance the productivity of the crop plants within the garden.
As you may have deduced from the previous section, the maintenance tasks within a perennial polyculture garden have very little to do with the typically tedious and labor intensive chores of a traditional monocrop garden such as weeding and watering, and much more to do with creativity and artistic design. The trick is to identify the problems your garden ecosystem is experiencing, and to incorporate additional elements in order to address those problems.
For example, a rockery may be built for the purpose of housing predators of insect pests such as snakes, frogs, toads and lizards. A rockery is simply a pile of rocks. It can be placed at the base of a plant which seems to be experiencing problems from pests. The rock pile should be built in such a way so it provides ample space among the rocks for the predator species' you wish to attract to move about, but should not be so strictly designed that it no longer has a character of randomness in its nature. Rockeries at the base of your plants will also help keep them well hydrated even during dry periods. Lengths of logs may be added for the same purpose, as well as to serve as benches for human garden inhabitants.
The taller elements of a garden may be especially useful for shading an area in freshly planted areas. However, once plants in these new areas become established, they may benefit from more sunlight. Similarly, small trees and bushes in the legume family may be used to fertilize the soil for future generations of plants. As they grow they may be subject to a practice called "chop and drop," in which the plants are pruned, and the pruned branches are dropped directly down onto the soil below, which benefits the soil with the nutrients within those branches, including the added nitrogen which plants in the legume family are able to obtain "for free" so to speak, from the air.
Nitrogen is not the only nutrient which may be freed up this way, as many plants normally considered "weeds" by traditional gardeners are actually nature's band-aids for the soil. The soil actually selectively grows certain plants when the levels of certain nutrients are low in the topsoil. These deficiency specific plants grow very long roots, reaching down well beneath the top soil in search of the nutrients of which the soil in the garden is deficient. As the plant grows its parts become a source of concentrated nutrients of which the topsoil is deficient, and the "chop and drop" pruning technique is a method by which the natural process of rebalancing the soil's nutrients may be hastened, as the pruned parts provide fertilizer and essential nutrients lacking in the surrounding soil to neighboring plants.
The key to success with the chop and drop method is to follow this simple rule; chop when the evaporation rate is lower than the precipitation rate - in other words, when more moisture is being added to the soil through seasonal rainfalls than is being to evaporation. When the evaporation rate is higher than the precipitation rate, however, neighboring plants and the soil itself will benefit more from the moisture protecting shade the targeted plants are contributing than they would from the sunlight and additional nutrients which the chop and drop would provide. The chop and drop method is especially useful when a garden is experiencing problems with crop damaging fungal infections, as fungus proliferates in gardens which are too tightly packed causing moisture levels in the air to be too high, which in turn causes the growth of fungii.
As you might imagine, garden maintenance in a perennial polyculture garden is more about creative problem solving than about forcing your garden to fit an approach which worked for someone else. Find out what your garden needs, and find a way to address that needs. My best hint is this: Learn to love your soil. Your garden is the soil. The soil is alive, it is an entity all its own. The soil may get sick, it may get injured. Make the needs of the soil your primary focus and everything else will fall into place on its own.