What Food Forests Are And How They Function
Food forests are production systems that try to mimic nature. Rather than growing trees in grass, we aim for a variety of plants of different shapes and sizes among the trees. Like natural forests, food forests include layers from the ground up. By selecting plants relevant to each layer, space can be used efficiently and competition reduced. We also want to replicate the interactions between animals, soil and plants that make a forest ecosystem function.
In 2010 I was invited by a Canberra primary school to revive its garden which was started in 2008 and develop a food forest. The following guide uses that project as an example (see green text).
Setting Goals And Budgeting
Start by setting goals and intentions for the space: why a food forest? what to grow? how much time and money do you have? Good goals will match the space you design and develop to your needs and expectations. It is easy to become overwhelmed by garden size and maintenance needs. By setting goals and understanding resources available you’ll develop a garden to enjoy, rather than make a burden for yourself. Start small, see how you go and what works, and plant more later.
The school community wanted a productive and aesthetic space that the children could use for play and to observe garden wildlife. It needed to be easy to maintain because it might not get attention during holidays, especially in summer.
We had a clear budget and deadline – one year. We allocated our money to infrastructure (water tank, irrigation, tools, tool storage, pathways, mulch) rather than plants (food forest plants are easy to grow and propagate), although we did buy some to kickstart the garden.
Investigating Your Space
After developing goals and a budget, the next step is to analyse site conditions. Determine the different areas of your space and what you can plant to enhance or ameliorate the site, for example: Mediterranean plants where it is drier; a windbreak to prevent damaged blossoms. A basic analysis should consider things like: direction of the sun, shade and winds; access to water and where it will pool and drain; soil condition; how plantings might affect surrounding buildings or infrastructure; and how people are currently using and interacting with the space.
The fruit trees received sun in winter and summer. There was a large deciduous tree to the west. Cold and hot winds blew across from the east and the west.
The area was flat, but the site was on the top of a small slope. Tap water was available from an adjacent building. The soil was a clay loam. There were no services below where we wanted to dig. The space could be seen from two classrooms. The fruit trees were disconnected from the rest of the garden with no path or invitation to enjoy the space.
Developing A Concept Design
Armed with goals, budget and site analysis, the next step is to develop a concept design. A good concept design should respond to the site analysis to show: the main trees and shrubs existing or proposed; pathways and access; wind direction and how you will manage that. Site conditions need not be detailed but rather give a general indication of different areas and treatment. Well-defined access is important to protect the soil, allow for pruning and harvesting, and paths can direct water flow.
One pitfall is planting the canopy layer too densely. If all the large trees grow so that their canopies touch there is no light left in the understorey for beneficial herbs and shrubs, which reduces the productivity of the space. Aim to maintain gaps of one to two metres between the tree canopies when they are mature; this requires both good plant selection and pruning. Trees should be no taller or wider than four metres for ease of harvest: when planting leave about six metres between the holes that are dug for two trees. If you live closer to the tropics you can plant closer together as the light is stronger. Denser planting is possible if you’re willing to keep plants watered and fed. If you are working in a small space this is easier than in larger gardens.
The school community needed to understand our ideas for the space and how it would function. We outlined things like: where we would plant windbreaks to protect fruit trees, and as habitat for beneficial birds and insects; where we could plant fruiting shrubs; location of pathways and water points. We took account of the likely foot compaction by children, and were careful with paths; one large path created as a swale also allowed access from the canteen.
The garden already had 12 fruit trees in an area of about 30 m2, planted closer than desirable. We decided to keep them and prune smaller for the children, or move those not doing well later. This area was to be a temperate garden with irrigation and a dense planting of shrubs and herbs. There was another patch of fruit trees – two fig trees and an almond – at a similar spacing: this was to be a Mediterranean space, not irrigated and planted less densely.
Designing The Details
With the broad structure defined you can move to the next step, designing the finer detail. One of the key elements is developing guilds for each fruit tree, i.e. groupings of plants that cooperate rather than compete. When a guild is well designed, plants will produce more than if they are grown on their own. The use of many plants in different layers means more productivity per unit area.
Any good organic gardening book will help you find out the needs of fruit trees that you can grow in your area. If you have no idea about which shrubs and herbs to use, keep an eye out for plants growing in local cottage gardens, as many of the herbs used will support beneficial insects and fruit trees nearby. Additionally, your local permaculture group or nursery staff will help identify suitable plants, and you might discover a source of plants to take cuttings from. Landcare or bushcare groups should be able to advise on local species that provide habitat for pest predators.
The main needs for fruit trees were pollination, nutrients, pest protection and ease of harvest. The garden lacked shrubs and herbs.
For pollination we planted clumping and running herbs from the daisy, carrot and mint families, with many small flowers to support pollinators throughout the year.
For nutrition we included comfrey and yarrow which mine nutrients from the soil and cycle them. Nitrogen fixing plants, such as wattles, were planted around the outside of the fruit trees to create wind protection, and could be cut back to feed the soil through leaf mulch.
We also wanted habitat for insect-eating birds; these tend to be small and like spiky shrubs for shelter. We needed plants that weren’t too spiky for the children, and chose local banksias and grevillias. Pest protection was also provided by the flowers above which support beneficial insects, and aromatic herbs that confuse pests, such as garlic, mint and tarragon.
Finally, we needed a range of plants that were easy for the children to harvest. The fruiting shrubs and herbs chosen included Chilean guava, currants, feijoa, raspberries and strawberries.
Once the design has been agreed to, the next step is implementation. It is usually best to implement incrementally, allowing time for reflection and observation. Some people prefer to plant all the canopy trees and then develop lower layers under and around these over time; others like to plant everything at once. The all-in-one approach has great instant effect but usually requires more time and a bigger budget. However, in temperate climates there is often variation in the ideal time to plant different plants which slows down the process: fruit trees bare-rooted in winter; herbs and shrubs during spring or early autumn.
Other things to consider include:
- infrastructure – regardless of your planting strategy, it is important to start with pathways and irrigation so that you can keep plants alive in a dry spell, and avoid mistakes
- clearing the site – if you are starting in a space that is grassed it is ideal to remove it using a chicken tractor or sheet mulch for example
- improve soil quality – encourage beneficial fungi to cycle nutrients and help the fruit trees access soil minerals; use woody mulch when you plant the fruit trees as this will contain spores and provide good conditions for fungi.
We ran garden days to which we invited the school community to develop the space and share the sense of ownership. At the first (March) we sheet mulched the couch grass around the fruit trees, and planted a range of shrubs and herbs.
The last step is to evaluate how you went with the previous steps. This supports informed decisions during ongoing implementation and maintenance, and about what you might do differently next time. What is growing well and what isn’t? how could you have improved the design? were there problems with infrastructure, e.g. sufficient water? are there gaps in layers/ functions? was the budget sufficient? A plan only exists to be deviated from as required.
Most of our shrubs and herbs did well. Occasionally the chickens escaped from their coop and their scratching reduced diversity in the understorey, but we propagated from what survived. The sheet mulch (newspaper) didn’t quite stop the couch, but it is no longer dominant.
Let’s Get Started
Hopefully this guide gives you the confidence to get started on your own food forest. If you don’t have much space, a few well chosen shrubs and herbs around fruit trees can demonstrate the benefits. Using these design principles, your garden should be productive and brimming with wildlife, so make sure you provide somewhere to sit and enjoy your food forest and observe things that will help you garden into the future.