Backyard Composting

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Nationally, more than 33 million tons of food is wasted each year. When discarded in landfills, decomposing food waste produces methane, which is a potent greenhouse gas that contributes to climate change.

Composting is the natural process of decomposing and digesting organic matter by bacteria, fungi, earthworms, sow bugs and other organisms. The resulting compost is a nutrient rich humus that can be used as a fertilizer and soil amendment. Of all composting options, home-based composting has lowest carbon footprint, since it requires no transportation and involves the least processing.

This page includes information specific to backyard composting. If you are looking for information regarding Evanston's Food and Yard Waste Services please see visit the linked page. It is important to note that the items that are allowed/accepted in the Food and Yard program differ from what is allowed in backyard composting. The two processes, although similar, allow different materials to be accepted. For example, no fats, oils, meats, dairy or grease should ever go in your backyard composting pile, but those items are accepted in the Food and Yard Waste Service.

Guidelines for Proper Backyard Composting

The following guidelines are intended to encourage good compost management techniques that accelerate the composting process, avoid nuisances and deter pests.

  1. The City of Evanston endorses the composting resources shared by the Solid Waste Agency of Northern Cook County (SWANCC) on their composting webpage at http://swancc.org, which includes information from the University of Illinois Extension, Cornell Cooperative Extension, US Environmental Protection Agency (USEPA), Earth 911 and many others, to promote good compost management.
  2. The City of Evanston considers the following materials to be acceptable for composting (source: USEPA):
    • Greens (nitrogen-rich): grass clippings, fruits and vegetables, bread and grains, coffee grounds and filters, paper tea bags or loose leaves
    • Browns (carbon-rich): leaves, twigs; shredded paper and cardboard rolls, sawdust, hay and straw, wood chips, egg shells, dried out flowers or plants, nut shells, wood ash, dryer and vacuum lint
  3. The City considers the following as unacceptable composting materials (source: USEPA):
    a. Meat, poultry, fish, bones, dairy products, fats, oils, grease, pet waste, soiled diapers, plastic, metal, glass, charcoal ash, large wood material, fire starter logs, treated or painted wood, waxed or glossy paper, synthetic fibers, weeds, diseased or invasive plants, black walnut tree leaves or twigs, yard trimmings treated with chemical pesticides, anything not biodegradable.
  4. Siting and proper maintenance of compost bins and containers can be effective in deterring rat and other pest animal populations through identifying nesting areas, restricting available food sources and other population control efforts. Backyard composting in an urban area requires careful adoption of these techniques to discourage rats and other pests. See http://cwmi.css.cornell.edu/nuisance.pdf for more information.
  5. Compost shall be maintained to prevent the harboring and breeding of animals and offensive odors. Good composting techniques to prevent odors and animal nuisances include, but are not limited to:
    • constructing the compost bin out of hardware cloth or welded wire.
    • locating the pile away from attractive animal nest locations like wood piles, carports, sheds or brush piles and away from attractive food sources like bird feeders, pet food bowls, garbage cans, fruit trees or berry bushes.
    • turning the compost pile and keep it moist to increase the temperature and speed up decomposition. This will also discourage animals looking for a dry undisturbed bed.
    • carefully observing the vents and other open areas of the bin to ensure food scraps are covered and that leachate is kept under control.
  6. Compost bins and containers must be constructed in a way that deters animal pests like rats and other vermin. Rats are able to chew through plastic bins, often starting with the vents, and may burrow under and into your compost bin.
  7. Recommended design features include:
    • a solid frame that can be covered by half inch hardware cloth or welded wire. For instructions on building a welded wire bin see: http://ccetomplins.org/compost/downloads/weldedwirebin.pdf
    • cover the entire bin in 1/4 to 1/2 inch wire mesh.
    • ensure the bin has a tight-fitting lid.
    • provide adequate drainage by digging out the soil below the bin and laying 3 to 4 inches of coarse gravel.

Landscaping to Control Rat Populations

In a 1996 study of rat populations in Boston entitled “Norway Rat Infestation of Urban Landscaping and Preventative Design Criteria,” the authors detail their efforts to characterize the properties of urban landscapes that make areas more favorable to rat harborage. 54 landscaped areas were evaluated for the presence of rats and by criteria such as type and coverage of shrubs, plant spacing, visibility, proximity to buildings, and others. Their findings are translated into actionable guidelines for the city and for homeowners below.

It must be acknowledged that any effort to control rodent populations that does not include efforts to greatly reduce sources of food will be largely ineffective. Rat populations do not solely live in nests and burrows in landscaping features - they can survive in a variety of environments regardless of efforts to remove harborage. With that caveat, below are strategies that can be employed by the city and individuals to minimize the risk of rat nests and burrows in landscaped features.

Guidelines for Landscaping to Control Rat Populations

  1. Landscape Design
    In general, dense plantings should be avoided whenever possible. This especially holds when the plantings are in close proximity to sources of food such as food vendors or bird feeding areas. Here, “dense” can be defined quantitatively as shrubbery that covers more than 30% of the available plot area. Open, windswept landscape designs are demonstrably less likely to provide harborage for rats.
  2. Plant Types
    Deciduous shrubs and broadleaf evergreens are preferable plantings to needled evergreens, as their loss of leaves in winter increases visibility and decreases harborage. In general, plants that grow in a vase-shape or upright fashion are preferable to those with open patterns that provide cover for rats. Native plants that support habitats for desired species such as the Monarch butterfly should be encouraged.
  3. Layout 
    Plantings should be kept at least 3 feet from buildings, walls, or fences and positioned and maintained such that, when fully grown, they do not make contact with walls. In addition, the use of gravel inspection strips 10-12” wide and 5-6” deep made with small rounded stones (¼” - ¾” in diameter) should be encouraged along walls, fences, or between rows of shrubs. These inspection strips force rats into the open and make rat trails more easily visible.
  4. Plant Maintenance
    Plants should be maintained to maximize visibility and minimize harborage. In particular, overgrown shrubbery should be removed and lower limbs of bushes (up to 12”) should be trimmed to improve ground-level visibility and limit the ability of rats to nest in shrubbery.
  5. Food 
    Rats have shown the ability to climb bushes up to 5 feet tall to eat berries and other foods. Plantings that provide significant sources of food for rats such as fruits or nuts should be maintained to minimize the availability of food.
  6. Water 
    Landscapes should be graded to avoid standing water accumulation that can serve as water sources for rats. Gravel or crushed stone should be used to prevent surface accumulation of water.
  7. Planters 
    In planters, hardware cloth made from 17-gauge galvanized screening with 6mm openings should be used to line the entire planter as close to the soil surface as possible while still allowing for plant growth. The cloth allows roots to permeate but makes burrow construction difficult. For plants with large roots, an “X” can be cut in the cloth and the root ball inserted through it; the cloth can then be reset and trimmed to fit snugly around the planting.
  8. Public Spaces
    Public plantings should be designed and chosen as to limit the amount of maintenance required to deter rat harborage.


    References
    C. A. Colvin, R. Degregorio, and C. Fleetwood. “Norway Rat Infestation of Urban Landscaping and Preventative Design Criteria”. Proceedings of the Seventeenth Vertebrate Pest Conference (1996) 1-1-1996