“Composting in Bear Country” Guidelines for the North Shore 1 This document has been jointly created by the North Shore Recycling Program , the North Shore Black Bear Society and the local Bear Aware representative to establish guidelines for composting and bear attractant management for North Shore residents. The information contained here forms the basis of our combined or separate community outreach on these topics and will help us provide consistent messaging to residents.
Introduction The intent of these guidelines is to provide you with the information you require to compost much of your kitchen scraps and yard trimmings successfully without attracting bears to your neighbourhood and habituating them to non-natural food sources. • North Shore Black Bear Society: committed to achieving the coexistence of people and bears in harmony through community involvement, education, research and non-lethal management. Report bear sightings (604) 990-BEAR. • Bear Aware: an educational program designed to prevent and reduce conflicts between people and bears in our communities; a local Bear Aware officer is hired seasonally by the NSBBS. • North Shore Recycling Program: making conservation second nature on the North Shore by moving the community from environmental awareness to sustainable action. NSRP (604) 984-9730.
Why Compost in my Yard? On-site backyard composting is the most effective and environmentally-friendly way to manage the organic ‘waste’ your home produces. • Metro Vancouver disposes of 3,000,000 tonnes of garbage annually (Ashcroft landfill, Burnaby incinerator, etc.); we have run out of places to put all this waste • 23,624 tonnes of garbage picked up curbside on the North Shore in 2006 (from houses only) • 25% of this volume is kitchen or yard material that can be easily and safely composted in a yard • 6,800 tonnes could be diverted from the landfill by backyard composting • Reduce your ‘carbon footprint’ by reducing reliance on trucking your waste all over BC • Create ~100 kg of free, organic fertilizer for your garden each year out of your ‘garbage’
Bears and Composting on the North Shore Improperly managed compost bins have the potential to attract bears to your home and neighbourhood, inadvertently providing an unnatural source of food for bears. This workshop will help you understand what are typicial bear attractants and how composting works so that you can manage both successfully.
What about Bears? About bears, what attracts them to our neighbourhoods and how we can prevent negative human-bear interactions in our yards and gardens.
Summarized from the final version of “Composting in Bear Country Workshop Outline” (dated November 6, 2008), a document jointly created by the North Shore Black Bear Society, Bear Aware and the North Shore Recycling Program.
What Attracts Bears? Bears travel extensively in search of food, and it is normal for them to pass through residential areas sited along ravines, green belts or near forested areas (i.e., most of the North Shore). Problematic human-bear interactions occur when bear gain access to sources of unnatural food and begin staying in urban areas. The first step to composting in bear country is to make sure that you are managing ALL bear attractants on your property in a safe and responsible manner. • Bears have a keen sense of smell and are attracted to certain types of fresh and decaying organic materials (a bear has the capability to detect an unwrapped fish head in a garbage can more than three blocks away!) • Bears may be attracted to your yard for reasons other than your compost pile (improperly stored garbage, fruit trees, bird feeders, pet food kepts outdoors, uncleaned barbeques, etc.) • Bear attractants include: fruit (fresh or rotting); fish parts; meats; other proteins; unrinsed eggshells; fresh grass clippings; grains; cooked foods; and oils.
What Can I do to NOT Attract Bears? Ensure that your home and yard do not provide easy food sources for bears. • Garbage. Make sure your household garbage is not an easy food source for bears: keep your garbage container clean; freeze odorous foods (such as skin, bones and packaging of fish, chicken and meat) until the morning of pickup; ensure garbage is properly wrapped or bagged to restrict odours; store garbage in your home or garage or in a secure enclosure; never place out garbage before the morning of your pick-up day. • Recycling: wash all containers throughly before placing in the recycling bin. • Fruit trees and bushes. Pick fruit as it ripens and promptly clean up any that falls to the ground. Very small amounts of whole fruits (1-2 only) can be composted in the centre of a compost heap. Larger numbers of fruit should be buried directly in the garden; dig a deep hole or pit, add fruit, and re-cover with 12-18” of soil. Fruit covered with less than a foot of soil is detectable to bears. • Compost: Dig fruit and vegetable scraps deep into the centre your compost pile, rather than leaving them on top where they are easily detected by bears’ noses. Materials that smell unpleasant as they are added to the pile tend to be undetectable if they are buried under 12-18” of compost. • Grass clippings. Leave your grass clippings on the lawn (“grasscycling”) to decompose and feed the soil. • Bird Feeders. Remove birdfeeders or hang them very high (visit Wild Birds Unlimited to see an effective design on display) and only put out small quantities of high quality bird seed without millet. • Barbeques. Clean you barbeque after each use. • Pet Food. Store and serve pet food inside. • Neighbours. Collaborate with your neighbours to ensure that your immediate neighbourhood follows all the preventative measures to reduce human-bear conflicts.
Science of Backyard Composting – How it Works An explanation about how composting works so that you can maintain a healthy and odourless compost heap that will not become a bear-attractant.
Composting – What is it? • • • •
Biological decomposition or breakdown of organic material by bacteria and other organisms The resulting material is called “compost”, a humus or dark, nutrient-rich soil conditioner Many different kinds of composting (worm, commercial-scale, backyard, anaerobic fermentation) This workshop is about backyard composting and how to compost safely in bear country
Decomposers Compost happens: everything organic breaks down eventually through the work of bacteria and bugs.
Micro-organisms • “Decomposers” are responsible for the chemical decomposition of organics into humus (compost) • Invisible to our eyes: bacteria, actinomycetes, fungi (mold) • Active in all temperature stages of a compost pile Macro-organisms • “Consumers” grind, chew and tear organic material making it suitable for the decomposers • We can see them: ants, millipedes, slugs, nematodes, spiders, wood bugs, flies, worms, etc. • Active mainly in cooler temperatures, i.e., in more mature compost heaps
Factors that Affect Decomposers’ Work • • • • • •
Food: carbon “brown” provides energy for bacteria; Nitrogen “green” is food for bacteria’s growth and reproduction. A balance of C and N is key. Air: oxygen required for aerobic bacteria (the ones that don’t make compost smelly) Moisture: micro- and macro-organisms require water to survive. Consistency is best when like a wrung-out sponge. Too dry: organisms don’t function or thrive; too wet: not enough oxygen Temperature: warmer temperatures speed up decomposition. Composting process naturally slows down in winter Particle size: increased surface area increases speed of decomposition (more room for bacteria to attach and get to work). Chopped food scraps and yard trimmings decompose more quickly Volume: 1 m3 is ideal; larger gets too hot and difficult to manage; smaller (e.g., Garden Gourmet) won’t retain heat as well so will operate at cooler temperatures.
The Key: Proportions of Carbon and Nitrogen, Moisture and Oxygen If the proportion of carbon-rich materials is equal to or greater than that of nitrogen-rich materials, compost will not attract pests and will result in a rich, moist, black, earthy-smelling compost. For a compost heap to work, it needs to be moist like a wrung-out sponge and well-aerated (full of oxygen). Nitrogen: • Nitrogen provides food for bacteria’s growth and reproduction. Also known as “greens” • Includes yard materials: fresh grass clippings, plant trimmings, manure • Includes household materials: fruit and vegetable scraps, coffee grounds, tea bags, rinsed and pulverized eggshells, human hair or animal fur. Carbon: • Carbon provides energy for bacteria to do their work. Also known as “browns” and are often “dry” • High-carbon yard materials: fallen leaves, sawdust, straw or dried grass clippings. • High-carbon household paper products: tissue paper, paper towels or napkins, cardboard (toilet paper rolls, corrugated cardboard torn into small pieces), egg cartons, coffee filters and newspaper torn into 1” strips and crumpled. Oxygen: • Oxygen permits the aerobic metabolic processes that keeps decomposers alive • Aeration mixes oxygen into the depths of the compost heap, reactivating the bacteria that decompose the organic material and that allow composting to happen • Aeration may be done with a “Wingdigger”-type tool, a pitchfork, a strong straight stick or a shovel • Moving compost from one pile to another is best done with a pitchfork • Aerating the compost without moving it from its present location is best done with a stick or “Wingdigger”-type tool. Î How to aerate: plunge a Wingdigger (or strong stick) straight down into the compost heap as deep as possible, and then pull it straight back up. Use a stabbing motion, not stirring or prying. This is less taxing and simpler than trying to turn your compost heap with a pitchfork or shovel. Page 3
Moisture (Water): • The compost heaps should have the consistency of a wrung-out sponge • The addition of kitchen scraps (“greens”) is usually enough to keep the compost moist enough • If compost is mainly dry “browns”, some addition of water may be required in late summer months • If the compost heap dries out, the composting process will cease (decomposers can’t live without water)
Making Compost – How to Compost Successfully 1. Site Selection for the Compost Pile or Bin What goes in the bin is more important than where the bin goes. But, here are some factors to consider when selecting the ideal site for one or several new bins or a designated compost heap: Convenience: • You will visit your bin at least once a week as you take out your kitchen scraps; make sure the bin is in a location that you are can easily access 52 weeks a year (e.g., close to the kitchen door, away from dripping trees, not in an unlit location, etc.). Drainage: • Fruits and vegetables are mostly water; as they compost, that water will drain from the bottom of your bin. Ensure your bin is in a location where water can drain away from the base (e.g., on soil). Ample Space: • You require enough room for the bin or bins, a place to hang or lean your compost turning tool, space above and beside the composter to maneuver when dealing with the bin, and ideally, space beside the bin for a garbage can full of autumn leaves. Rodent-Free Zone: • Mice and rats love to live in thickets of plants that never get disturbed and that provide year-round shelter; do not place your compost bin in an area overrun with ivy or similar weed. Warmth • A healthy compost heap works best in warmer temperatures. If you have a choice between a warm spot (e.g., sunny or near the dryer exhaust) or a shady cool spot, select the warm or sunny spot.
2. Methods of Adding Materials There are two broad categories of backyard composting of kitchen and yard organic materials: Hot Composting (All-at-once) • Large volumes (~1-2 m3) of organic materials (carbon-rich and nitrogen-rich) are combined into a pile or bin all at once with small amounts fresh manure, soil, or finished compost (to introduce microorganisms, “inoculant”) • Within a few days, core temperatures will rise to over 50°C and then begin to decrease. Turning or aerating will bring in more oxygen and bring the temperature back up • Hot compost piles yield finished, useable compost faster than cool, or passive, compost piles • Hot composting tends to destroy most weed seeds, roots and rhizomes. • Stockpiling enough materials to create a hot compost can present problems for the backyard gardener; rarely are enough materials available on hand all at once, and stockpiled “green” materials rapidly become slimy and smelly, attracting rodents and bears.
Cold Composting (Incrementally) • Small volumes of both carbon-rich and nitrogen-rich materials are added incrementally – as they become available - eventually forming a pile • Nitrogen-rich (“green”) materials must be alternated with carbon-rich (“brown”) materials • Every time kitchen scraps are added, they should be buried under a layer of “browns” • Cold piles are ineffective at reliably killing weed seeds, roots and rhizomes • As materials are added incrementally, so too is compost created incrementally • This is the method used by most residents due to its simplicity Regardless of the method used - all-at-once (“hot”) or incrementally (“cold”) – the key to successful composting is the addition in equal amounts of “browns” and “greens”. An excessive proportion of “greens” leads to slimy, smelly compost heaps that attract rodents and bears. A preponderance of “browns” will result only in a slower-to-compost heap, but will not attract pests.
3. Tending the Compost Pile or Bin Composting is a very forgiving process. If you always add “brown” carbon material in equal or greater volumes than the “green” nitrogen materials, if you keep the pile well-aerated and you make sure it does not dry out, compost will happen. If you get off the right track, you can remedy a bad compost heap by balancing the carbon:nitrogen ration and aerating frequently. Compost will still happen. Since you live in bear country, you do not want to risk your compost heap becoming smelly. “Browns” should be added with every single addition of kitchen scraps, covering the scraps completely (never leave food visible) and aeration should be done at least every couple weeks, always finishing off by covering with more “browns”. These best composting practices are key to preventing odours which can attract bears.
4. What Should Result • •
Properly constructed and maintained compost piles do not emit any foul odours; they smell earthy. Resulting compost will be very close to pH neutral (that is, neither acid nor alkaline; pH=7)
Troubleshooting Compost in Bear Country: Q&A Some anticipated composting questions and how they could potentially be addressed.
Bears have already been into my compost; how do I make them go away? First, cease adding bear attracting-foods to your bin and top off the bin with “brown” materials. Second, check your home and yard for other bear-attractants. Third, empty the existing compost and dig it deep into a garden. Fourth, start again and ensure that whenever “greens” are added, they are buried under a layer of “browns”. If you know bears regularly explore your neighbourhood, do not compost bear-attracting foods: meats, fish, eggs, whole or rotten fruits, grains, oils.
What should I do with the fruit from my trees? Harvest your fruit immediately as – or just before – it ripens. Pick up fallen fruit immediately. If you only have one or two fruits, you may bury them deep within your compost heap, covering them with carbon-rich material. A better alternative for greater numbers of fruit is to dig a deep hole in your garden and bury the fruit under no less than 12-18” of soil where it will compost underground. Under no circumstances should you leave fallen fruit on the ground or pile fruit on top of a compost heap. If you don’t know what to do with all the harvested fruit, or if you need help harvesting it all, the North Shore Edible Garden Project wants you to feed your community and not the bears by donating your harvest. Food drop-offs are located in various places across the North Shore. www.ediblegardenproject.com
What should I do with egg, meats, grains, fish and oils from my kitchen? If you live in an area visited by bears, you are advised not to compost any meat or fish, grains, oils or eggs. Like any other organic materials, these will decompose aerobically if properly composted. However, these Page 5
foods are attractants and excellent food sources for bears. It is advised that these foods – especially the most aromatic of them - be bagged and frozen and only placed out in the morning with your other residential garbage on pick-up day. Frozen or thawing food will not be smelly enough to attract bears before garbage pick-up. If you would like to keep meat bones out of the garbage stream, speak to your butcher; many butchers take back meat bones for processing into bone meal.
Why does my compost smell so bad? It is likely that your compost contains mainly nitrogen-rich materials (i.e., kitchen scraps). Food scraps have a high moisture content and your compost is fermenting due to the absence of oxygen in a waterlogged situation. The products of fermentation include ammonia-like substances and hydrogen sulfide (which smells like rotten eggs). To remedy this, you need to add carbon and oxygen and reduce moisture. By adding a large volume of dry leaves, shredded newspaper or household papers (egg cartons, paper towels, etc.) and aerating your compost heap, you will be well on your way to reducing smell and creating “black gold” compost. In the worst case scenario (heavy, wet, slimy, stinky unmixable goop), bury the goop in holes 12-18” deep in the garden and cover with soil - it will compost in situ. Then, start your compost heap again.
How can I compost dog waste or kitty litter? Due to the likelihood of disease organisms that will not be destroyed by cold composting (the style of most backyard compost heaps) these materials should never be added to your backyard composter. However, dog and cat feces and used kitty litter can be composted in a dedicated, below-ground pet waste composter, also called a digester. (http://www.cityfarmer.org/petwaste.html). If you do not opt to compost your cat or dog feces, the proper way to dispose of it is to flush the feces down the toilet so it can be treated along with other sewage at the sewage treatment plants. Clumps of kitty litter, twigs or stones should not be flushed; they can clog or damage sewer lines. Poo-filled plastic garbage bags burst when crushed into the back of garbage trucks, which is neither pleasant nor sanitary for garbagemen.
How can I compost weeds? Most backyard compost piles do not heat up enough to kill weeds, so just-pulled weed seeds and weed rhizomes should not be put in a backyard compost pile. However, weeds contain many nutrients that they have pulled from your garden’s soil and you might wish to keep those nutrients for your garden. There are three ways you can compost your weeds without re-introducing them to your garden soil. 1. Completely dry out weed parts on a sunny sidewalk or driveway. Only once they are crumbly, place in the compost heap. 2. Create a dedicated ‘weed bucket’ to drown weeds: fill a lidded bucket with water and add weeds; they will anaerobically decompose (will smell) and the resulting green liquid can be used directly in the garden as fertilizer. 3. The last option is to place weeds in your Yard Trimmings container for municipal collection (but you’ll lose all the nutrients from your garden that the weeds pulled from it).
What is “Rot It” or “Compost Accelerator”? Various products are sold as "compost accelerators" and "compost activators". The products are usually a mixture of lime and weak synthetic nitrogen fertilizer, neither of which is necessary in a pile that contains the right proportions of “greens” and “browns”. Adding additional nitrogen fertilizer to a compost heap full of high-nitrogen kitchen scraps (“greens”) will exacerbate slime and smell problems, not solve them. The addition of carbon (“browns”) and oxygen will cure a smelly, wet and slimy heap of food wastes.
How do I make sure I have enough carbon “browns” in my compost? If you are composting your kitchen scraps, you most likely do NOT have enough carbon in your composter – most people don’t. The best option is to hoard fallen leaves in autumn. Gather them into one or several garbage cans with lids and place a can beside your composter with a pair of tongs inside; each time you add kitchen scraps, grab a large scoop of leaves and add them on top. To keep carbon levels high year-round, here are some household items you can add. Line your kitchen compost bucket with some sheets of Page 6
newspaper; when the bucket is full, dump everything – including the newspaper – into your composter (keeps your bucket cleaner, too). Rather than recycling cardboard rolls from toilet paper, and put them in your composter. Don’t throw paper tissues, towel or napkins in the garbage; compost them. Shred paper egg cartons and add them to your composter. Another last-resort carbon source comes free to your home each week: newspaper can supply large volumes of carbon until the leaves fall. Shred newsprint or tear into 1” strips, crumple them, and add them to the compost bin.
Is soil “Brown”? No. Soil is not a high-carbon material. A form of soil is what you are creating by composting carbon and nitrogen-based materials. Soil is not a substitute for dry leaves or low-grade paper products.
Do I need to add lime to my compost heap? Dolomitic or garden lime is a natural substance (crushed dolomite limestone) that reduces the acidity of soil and provides calcium and magnesium, important micronutrients for plants. Bacteria do not digest limestone; the addition of lime to a compost heap does not influence the biological and chemical composting processes and is not necessary. If a compost pile is too alkaline (by adding too much lime or wood ashes) or acidic (by adding too much sawdust or cedar or pine needles) bacterial activity will slow or cease. On the North Shore, our soil tends to be acidic. If you need to make your soil more alkaline, add lime directly to the soil, not the compost. Concentrate on feeding the compost microorganisms what they need: carbon, nitrogen, oxygen and water.
Do I need to add soil to my compost heap? No. The only biological reason for adding healthy soil or finished compost to a new compost heap is to “inoculate” it, i.e., introduce the bacteria and bugs that are required to do the work of decomposing food scraps and yard trimmings into finished compost. A composter sited on soil will not require inoculating; all the bugs and bacteria are already there. Soil doesn’t add any carbon or nitrogen; soil is essentially what you are creating by composting. Some people choose to add soil in thin layers (1/8” maximum) to complement the finished compost’s texture.
Do I need to aerate my compost heap? Yes. Because you live in bear country, you should aerate your compost heap regularly, i.e., at least every couple of weeks. By not aerating, you risk allowing parts of the bin to lack oxygen, resulting in a smelly compost heap, which will attract bears. Aeration will also result in compost being created more quickly.
What if my grass clippings or plant materials have been treated with pesticides (‘Weed ‘n Feed’ products, insecticides or herbicides)? Both the Districts of West Vancouver and North Vancouver have pesticide restriction bylaws in place and you should not be using these chemicals in your yard. There are many good alternatives to pesticides and pestpreventing gardening practices that you can use instead (gardensmart.ca). The best method of keeping a compost functioning properly is to ensure the health of the microbes and other organisms within the compost heap that are doing all the work for you and to make sure they have all their requirements met (water, oxygen, nitrogen and carbon). Obviously, adding chemicals which are designed to kill insects will have a negative effect on the health of your compost heap, killing the very critters that you are relying on to break down your organic materials. We suggest composting pesticide-laden materials in a separate heap (i.e., not with your kitchen food scraps) that can sit undisturbed for a year or more, letting it slowly compost and cure. (November 2008)