Site design
Long-term planning and mapping of the garden will help lead to improved soil health and water management, limiting nutrient loss and building resources for the future. One of the first steps in site design is to understand the natural flow of rainwater and nutrients across the landscape, determining where and how runoff water enters the land and where it exits. The runoff from upstream is often full of nutrients, including animal manures, organic material and topsoil. Managing water flow is an important way of capturing and delivering these nutrients to a garden and preventing them from leaving it.
The aim is to effectively control water during the wet season and to access it during the dry season. Once water flow is understood, basic agronomic practices can be employed to capture the water. In this way the gardener can build a garden that slows the water on the land, allowing it to spread and sink into the soil.
Size and location
A permagarden can be located anywhere near the home. The size should be related to the amount of water available and the level of energy the gardener is willing to commit. Permagardens can be as small as 2 m2 (e.g., 1 m by 2 m) or as large as 100 m2 (e.g., 10 m by 10 m). In land-constrained areas, such as urban and peri-urban plots, or in refugee or internally displaced person (IDP) settings, the permagarden approach can provide an important source of food production when traditional vegetable growing is extremely difficult. In the dry season, garden beds can be scaled down to accommodate reduced water availability.
A good starting size for a typical household garden in a FFP program is
16 m2 (e.g., 4 m by 4 m). More space can be added later, depending on family commitment and desire to expand, but it is important to start small. Beginning with a large space can quickly become too labor intensive and discourage farmers from continuing. Starting small provides the possibility for further expansion to meet family needs, and more effectively utilizes scarce resources, such as water. Once a farmer has the understanding and skills to manage an effective garden, then he or she can explore increasing the size of the garden to produce more vegetables than the household can consume to be sold in
the market.
Choosing the best location for the garden at the homestead is important. The garden should be close to the home to allow for easy management.
Key characteristics of an ideal permagarden site:
Receives full sunlight at least 4 hours a day. Accessible to all family members.
Protected from extreme winds, livestock, or other damaging elements.
Contains soil that is relatively free of rocks.
In addition, there are many natural influences that may affect the garden, such as the sun’s movement across the land or the slope of the land. A few natural influence considerations when choosing the garden site include:
In hot locations with a strong sun exposure, choose a site with shade or partial sun for part of the day.
Place the garden downslope from a chicken coop or kraal (while still protecting the garden from animals) to allow gravity to bring manure and nutrients into the garden during a rain.
Place the garden away from the trash pit or other hazardous materials.
Garden design and layout
After the garden site is chosen, it should be cleared of rocks, weeds, and other debris and then lightly cultivated—using a hoe to remove weed and grass roots that are just below the surface. As long as they have not gone to seed, these removed weeds and grasses can be used later in the composting process once the roots have completely dried out.
The gardener can control water flow into and through the garden for maximum use. It is therefore important to determine where rainfall will enter the garden and how water will flow through the garden. As water flows down slope across the land, it carries nutrients from other areas, including manure and biomass. The aim of the garden design in dry regions is to encourage these nutrients to flow into the garden and to sink into the soil, especially for use in the dry season or during dry periods in the growing season. Likewise, good design can help mitigate flooding in wet regions by diverting excess water away from the garden, preventing crops from getting waterlogged.
The flow of water is controlled through effective design and integration of technical practices, such as double digging, composting, close plant spacing, and mulching, combined with the appropriate use of swales, berms, holes, beds, pathways, and fencing. Using these techniques can significantly increase the amount of water infiltrated into and stored in the soil.6 All of these components should be planned out on the cleared site. Each one of these components is discussed in greater depth later in this manual.
For more information, Creating Drought Resistant Soil http://www.fao.org/docrep/009/a0100e/a0100e08.htm
Since permagardens are designed to obtain the greatest benefit for the farmer and the garden, each garden design will look different depending on the context. Example instructions for planning and designing a permagarden are listed below. When drawing the lines in these instructions, it might be helpful to have string and stakes to plot the design. Make sure that the garden plan allows for enough space for a fence to surround the garden.
Basic garden design or layout
One example of how to plan and layout a permagarden
- Step back from the cleared garden area and look for the steepest change in elevation from top to bottom. This change in elevation is called the ‘slope’. A swale(s) or ditch(es) should be placed to capture water as it flows into the garden. It is best to place the swales on the upslope side, at the highest point, to stop the water before it reaches the garden beds. This helps to protect the garden as it captures the main flow of water and nutrients from upslope, and allows the water to seep into the soil and move slowly towards the garden beds below the surface.
- Draw a line along the side of the garden where the swale is planned. Keep the points of the line at the same elevation by using the A-Frame (explained in Water Management section ). This line forms the border of the upper part of the top swale.
Permagardens are designed based on the specific garden site.
Photograph: Eric Carlberg
- Draw a second line parallel to the first line down the slope. These two lines mark the entire upper swale. The swale should be large enough to hold
all the rainfall that will flow into it during a rain (approximately 50-100 cm wide). Note: Often the swale will not be in a straight line because the contour of the land is not straight.
- At one end of these two lines draw a 75 cm wide circle. This marks the receiving hole that will capture water coming into the garden that overflows from the swale.
- Envision this hole filling with water. As the water slowly overflows out of the hole, it should be directed along the side of the garden so that it does not flow into the garden beds. Draw an outline of a swale along the side of the garden that will carry this water down the slope eventually into another hole (i.e., an overflow) that will be part of the side swale.
- Draw a line parallel to the swale, approximately 50 cm toward the outside of the garden. This is the side berm.
- Draw a lower swale, along with an approximately 50 cm wide berm on the outside of the garden and hole, the same as the swale at the top of the garden.
- Draw a parallel line approximately 40 cm down the slope from the upper berm. The area between the berm and this line form the upper permanent pathway.
- Draw another parallel line approximately 1 m down from this line. These two lines (the line at the bottom of the upper permanent pathway and the line drawn in this step) outline the first garden bed.
- Below the first bed, repeat Steps 8 and 9 to create the outline of as many
1 m wide beds as the space allows. In dryer regions, the garden beds should not be raised in order to conserve soil moisture.
There are no exact measurements for the swales, holes, and berms. Some are straight and some may be curved, depending on the contour of the land. The size of these water harvesting structures also depends on how much water enters the garden site. If the garden is downslope from a large catchment area, or if
the area tends to have heavier rainfalls, then the swales may need to be big. If the garden is in a refugee or IDP camp with limited space, the water harvesting structures may be small. The most important point is to place the water harvesting structures on contour. If they are not on contour, then water can flow out of the garden and be lost due to poor design. This is covered in more depth later in the manual.
The design of the garden can be continually adjusted. A gardener should gather feedback from the garden and make adjustments as necessarily. For example, if the gardener notices a swale fills up when it rains then the swale can be enlarged or an overflow added.
