Rising Roots Permaculture: Permaculture Information

Permaculture Design

How to Perform a Site Analysis of Your City Lot

a 6 page excerpt from Paradise Lot on how to do site analysis and assessment on an urban lot; based on a story from the transformation of an empty lot in Western Massachusetts into a edible paradise.

What is the overall pattern of the land? What are the opportunities and limitations? What potential can be unlocked through regenerative land use?

Draw maps of your site; each time viewing it through a different lens: soils; sun and shade; slope.
Think of the effect each of these characteristics will have on the garden's ability to grow.

Analysis: observe current conditions on a piece of land; objective

Assessment: interpret the results of your analysis through the lens of your goals for land use; evaluate

Observation: observe the site through a full year cycle of changes; note seasonal patterns of sun and shade
-Ask yourself: Where is the sun hitting in the early morning and late afternoon? What about in the late morning and early afternoon? What is still shaded in the middle of the day? How does this pattern change throughout the seasons?

Microclimate: a local atmospheric zone where the climate differs from the surrounding area
-Are there areas of your site that are protected from cold winter winds, such as from a building?
--This may make that area a warm, sheltered microclimate zone with a longer growing season.

Sun and Shade: The angle of the sun in different season in relation to structures, trees, and other shade creators may affect which areas of the land receive sunlight at different times.
For example, the low angle of the winter sun may shade an area

For example, one area of your land may be shaded by a house that blocks the low angle of the winter sun, but may have full sun in summer when the sun is at a high angle above the house. Conversely, a low-angled winter sun may be able to shine through under a canopy of trees, while the high angle of the summer sun will be blocked by the same tree canopy and shade the ground below it.

Some ways of recording data on sun and shade patterns:
-take pictures from a high elevation of the whole piece of land at different times of day and throughout the seasons
-draw the shaded areas on a sketched base map at different times of day and throughout the seasons
-use a "solar path finder": a tool that can be bought or home made to show the average sun path for a given month

Is there only one or a few areas of your site that get full sun for most of the day in both winter and summer? May this be the best place for a greenhouse, an annual garden, or your most food-growing intensive perennial bed?

Soil

What is the soil quality in the lot? Are there different soil types and qualities in different parts of the land?

You may want to look into the history of the site to see if building existed here at one point, if there were other types of construction and demolition, or if there were any industrial uses of the site at one point.

You may find that your soil is of good quality and good aeration and drainage, or you may find that there are toxins in the soil and that it is compacted from construction equipment or other causes. Compaction will affect the drainage and aeration of your soil.

Estimate what portion of your soil is clay, loam, or sand. How much organic matter seems to be in your soil? Organic matter is created through the decay of plants and other organic materials and can be added to your site through composting. Check out this link for a brief description of soil components.

Are there piece of concrete, brick, and asphalt in your soil? What about plastics, glass, and metals, and if so, how deep down does the mixed in rubble and trash go? Maybe only the first 6 inches of soil have these kind of materials in it.

Soil testing in a lab will tell you what levels of mineral nutrients are in your soil. Soil testing at the University of Massachusetts-Amherst is fairly easy and inexpensive and will also give you suggestions about how to raise the levels of certain mineral nutrients if they are too low for what you desire to grow. Look at the Sampling Instructions for Routine Soil Analysis here for how to take your soil samples and send them to the lab.

These soil tests will also tell you what your pH level is and whether there is an issue of medium or high levels of lead contamination. You can raise or lower pH by adding certain soil amendments such as sulfur, limestone, or pine needles. If lead levels are higher than desirable, you may choose to only grow fruiting trees and supporting, non-edible plants in these areas as fruit tends to take up much less lead than do leaves and roots. You may also choose to plant species for a certain amount of time that will take up the lead, and then remove these plants before future plantains - a process called bioremediation - or add organic matter, mulch, and refrain from tilling to decrease the parts per million of lead in the soil by building more uncontaminated soil.

What plants and vegetation are already growing on site can clue you in to other information about your soil. Identify what species are already present and in what areas they each grow. Look up more information about those specific plants to see if these plants reflect upon the types of soil they are growing in.

Water

Take note of the rainfall your site gets throughout the year. Are there concentrations of heavier rain falls in certain months than others? Are there entire seasons of mostly dry, rainless months? This will affect the degree to which you can irrigate from water you capture with rainwater collection techniques, such as channeling the rainfall on roofs into buckets and cisterns.
This will also affect whether you can dig swales, ditches and berms along contour, and other earthworks to capture, sink, or direct rainfall and groundwater to irrigate all parts of your land. For these reasons, you will want to find what the slope of the land is. You can do this using an A-frame, a basic tool for assessing slope, to get an idea of the topography of the land.

Wind

Do houses, buildings, and structures form wind tunnels that direct heavy winds on to your site? Are you close to an ocean, bay, or other body of water that will create winds, fogs, or temperature changes? This may inform whether you will plant tall trees or hedges to create wind breaks in the future, or what you will plant where to give more sensitive plants a more protected place in the design.

Study the ecological neighborhood.

Evaluate food, water, shelter, and other factors that will impact populations of beneficial insects and birds that eat pest insects. Maybe there is a stream nearby, bees and butterflies already flying around, and wildflowers blooming; or maybe there is no open water, few sources of nectar for insects, and little plant food for birds and other creatures.
Is there a diversity of habitats and successional stages on your site, or is habitat, land form, and patterns of plants fairly uniform throughout the whole site? Is there cover and habitat from evergreen hedges, thicket-forming shrubs, brush piles, or other groupings of plants? This will determine whether there is a healthy home for pest-controlling insects, birds, and other creatures.

Legal Restrictions

What are the legal restrictions that pertain to your site and the projects you may want to do there? In many cities, sustainable and regenerative practices like composting toilets and keeping chickens are illegal. See if there are laws around keeping of livestock and use of greywater. These legal restrictions are aspects of the site that must be included in your assessment and analysis, not that you must follow all the rules, or any of them.

Putting it All Together

How do all of the factors that you have assessed relate to each other? One way of seeing this is to lay different site maps you have drawn to depict sun, shade, soils, wind, and other elements over each other to see where on the map there are special combinations of factors or incongruencies that may prevent you from doing something desirable. As you assess the conditions, challenges and limitations of each portion of the site you will be able to analyze the suitability of various elements you want to include in each of these spaces. For example, does the compost bin get positioned near the kitchen for easy access even though it's the spot that gets the most full sun? Or is this space better reserved for intensive food growing? How does the roof of a tool shed being able to collect rain water at the highest point of elevation relate to how the structure might block the low angle of the sun in winter?

As Eric Toensmeier writes, now you need to come up with, "an overarching vision to tie it all together, a layout that would harmonize with the patterns of the landscape." From site analysis and assessment, you will go forward to looking at designing by zones and sectors, to create the most relationships between the elements in your system, and to maximize the use of energy while minimizing the need for expending unnecessary energy.

(Much of this was originally written by Eric Toensmeier in the original article linked at the top of the page. It has been rewritten in some cases and copied verbatim in others to make it more of a how to and to inspire questioning, rather than its original story format. For the original story and case study of Eric Toensmeier's lot in Massachusetts, see the original article linked at top of the page.

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Companion Planting Chart

Nutrition Information

Food pH Chart: Most Alkaline and Acidic Foods:

http://alkaline-alkaline.com/ph_food_chart.html

Soil

The Soil Food Web