The Compost Heap

Basic Composting in Alaska

by Heidi Rader, Extension Faculty
Agriculture and Horticulture

HGA-01022

Composting is a great way to make a nutrient-rich soil more. You can also accelerate decomposition in a pile
amendment while effectively recycling table scraps and by turning it frequently, but it is not as easy as with a
yard waste. Alaska’s short, relatively cool summers can tumbler. In addition to convenience, tumblers are also
make proper composting a challenge, but you can take good for containment and neatness. Moisture regulation
steps to hasten the process and ensure a healthy soil is also easier in a bin than in an open pile.
amendment is available to add to your garden.
Some Like It Hot
What is Composting? Initial decomposition is begun by mesophylic organ-
Composting is a way to accelerate the natural decom- isms. As the compost heats up, the thermophilic, or
position process by balancing the carbon to nitrogen heat-loving, organisms take over. If your pile is at least
ratio (C:N) and providing adequate air and moisture to 3 cubic feet with the right combination of carbon and
heighten microbial activity. nitrogen materials, water and air, the interior tempera-
ture will quickly rise to between 120 and 160°F. The
To Bin or Not to Bin? hot phase will last several days if the pile is turned
A simple above-ground pile, at least 1 cubic yard in frequently.
size, works well. The size is important since it must
be large enough to keep the internal temperature high Composting Materials
enough to kill pathogens and weed seeds. Some contain- Fast decomposition requires the proper mixture of ma-
ers may be smaller than this if they provide insulation. terials. Each organic material source has its own unique
C:N ratio.
Containers have advantages, especially when compost-
ing fish or nonmeat kitchen wastes like moldy bread or
carrot tops. There are many designs for containers; you
The Carbon to Nitrogen Ration
A carbon to nitrogen ratio of approximately 30:1 (by
can even use an old puppy pen. Wire bins are inexpen-
weight) is optimal for the process of hot compost-
sive and simple to build and they keep most pests out,
ing to work. This average 30:1 ratio results from
but they should be easily disassembled and reassembled
mixing a combination of high C:N materials (often
for turning the compost. For both piles and containers it
called “browns”) with low C:N materials (often called
is important to consider proper air flow (high air pen-
“greens”). For example, straw has a high C:N ratio of
etration, how-
80:1 while fish has a low C:N ratio of 15:1.
ever, reduces
heat retention). This variable C:N ratio often causes confusion and
Tumblers, frustration for beginning composters who are trying to
while expen- utilize a wide range of materials (and amounts of these
sive, make it materials) mixed together to achieve the required 30:1
easy to turn ratio. These materials can be broadly characterized as
the compost, a source of carbon (browns) or a source of nitrogen
thus accelerat- (greens). The designation is determined by whether the
ing decom- C:N ratio is greater than 40:1 (brown) or less than 30:1
position even (green).
 Material C:N Ratio Green or Brown? you get close to a 30:1 ratio. Once you have calculated
Poultry manure 3:1 to 15:1 Green how much of each material you will need, you are
then ready to shred your materials, weigh the materials
Food waste 15:1 Green on bathroom scale and layer them, alternating carbon
Grass clippings (brown) and nitrogen (green) while adding water. When
(green) 19:1 Green you reach 50 to 60 percent moisture (“wet sponge”
Cow manure 20:1 Green consistency), you can sit back and wait for the compost-
ing process to happen, usually 6 to 24 hours. Other free
Horse manure 20:1 to 50:1 Green or brown compost calculator websites that you may find useful
Coffee grounds 20:1 Green include:
Garden stalks yywww.klickitatcounty.org/SolidWaste/fileshtml/or-
and leaves 25:1 Green ganics/compostCalc.htm
Leaves 35:1 to 85:1 Brown yywww.martindalecenter.com/Calculators1_2_
Grass clippings Ag.html#AGRI-FERT-COMPOST
(dry) 70:1 Brown yywww.agric.gov.ab.ca/app19/calc/manure/manure.
Straw 80:1 Brown jsp
Paper 170:1 Brown
Compost Recipes (by weight)
Newspaper 400:1 Brown Recipe No. 1
Sawdust 200 to 750:1 Brown 2 parts dry leaves
2 parts straw or wood shavings
Selected examples taken from "Compost Fundamentals:
1 part manure
Carbon-Nitrogen Relationships," 2009 web access, Whatcom
County Extension, Washington State University, http://what- 1 part grass clippings
com.wsu.edu/ag/compost/fundamentals/needs_carbon_nitro- 1 part fresh garden weeds (that haven’t gone to
gen.htm, and "Home Composting," Cornell Waste Manage- seed)
ment Institute, http://cwmi.css.cornell.edu/compostbrochure. 1 part food scraps (green)
pdf
Recipe No. 2
3 parts dry leaves
1 part fresh garden weeds (that haven’t gone to
Calculating the C:N Ratio seed)
It is said that composting is both an art and a science. 1 part fresh grass clippings
The science comes into play once the composting pro- 1 part food scraps (green)
cess begins, after the optimal 30:1 ratio is achieved. The
art comes from the trial-and-error discovery of the right Recipe No. 3
30:1 recipe, developed from mixing differing amounts 2 parts dry leaves
of your available organic materials together. 1 part food scraps (green)
1 part fresh grass clippings
Fortunately, there are effective shortcuts available to
fast-track the art of composting. Compost calculators Recipe No. 4
have been developed that take much of the guesswork 1 part dry leaves
and discovery time out of the compost process. One of 1 part fresh grass clippings
the best is a free web-based compost calculator from
Recipe No. 5
Green Mountain Technologies (see “References”). This
1 part dry grass clippings
compost calculator uses drop-down menus with various
1 part fresh grass clippings
organic compost sources. You select the sources and
the amount (in pounds) of each source, and the calcula- Recipe No. 6
tor adds it up and gives you the total C:N ratio of the 1 part fish waste (carcass)
mix, as well as moisture and bulk density. You add or 1 part sawdust
subtract the amounts of each of your materials until 1 part green materials (lawn clippings)
Procedure for Fast (Hot) Composting
Step 1: Gather enough organic materials to make a
pile at least 1 cubic yard in volume. Use the com-
posting calculators or recipes to determine how
much of each material is needed. Chop or shred any
coarse materials. Ideally, material should be chopped
into ¼-inch to 1-inch pieces.

Step 2: Layer carbon and nitrogen materials in ap-

propriate ratios, mixing with a pitchfork.

Step 3: Water as you mix to ensure that all the materi-

als are as damp as a wrung-out sponge (50 to 60 percent
moisture content). It may be helpful to cover the pile
with plastic or a tarp to control moisture levels.
material in compost improves soil structure, increases
Step 4: Use a long-stemmed thermometer to monitor the soil’s ability to hold nutrients and enhances the soil
the temperature in the middle of the pile. A hot com- food web.
post pile should reach a temperature of approximately
150°F. Moisture levels of 50 to 60 percent should also Mix 1 to 3 inches of cured, screened compost into your
be maintained. garden, lawn or perennial bed prior to planting, or add 1
to 3 inches as mulch to your plants in early summer.
Step 5: After the pile has reached its peak temperature
(approximately 150°F) and its temperature starts to de-
Things to Avoid
crease below 120°F, it is ready to be turned for the first
yyDo not add diseased plants, weeds that have gone
time. If peak temperatures do not reach 150°F, the entire
to seed, woody materials, grease, fat, meat scraps or
process may still proceed, but at a slower rate.
bones (other than fish) to your pile.
Transfer material from the outside to the inside of the
yyDo not add dog, cat or pig manure to your compost
pile. A pitchfork is a useful tool for this. Continue to
pile if it’s intended for your vegetable garden. Para-
turn the pile after it cools down and check the tempera-
sites found in these manures can survive the compost-
ture the next day.
ing process and remain harmful to humans (Refer to
Step 6: Once the compost no longer heats when it is USDA’s Composting Dog Waste, for more informa-
turned, the maturation or “curing” phase begins. Al- tion on composting dog waste).
low to cure for 4 to 12 weeks. The cool pile is recolo-
yyDo not add excessively high carbon (brown) materials
nized by nonheat-loving organisms. These organisms
to the soil because they will force the existing micro-
decompose the resistant carbon compounds, shift the
organisms to “rob” the surrounding soil of nitrogen,
compost’s pH from acidic towards neutral and convert
delaying and reducing the availability of nitrogen
organic nitrogen into plant-available nitrates. The cool
fertilizers applied to your garden.
pile is also recolonized by soil organisms that help
suppress disease in the compost. The curing process yyDo not apply uncured compost to sensitive horticul-
is longer and more important if the hot process was tural crops since some of the compounds can “burn”
incomplete. Completed compost smells more like soil the plants. Properly cured compost won’t harm the
than its original materials. plants.
Step 7: Consider screening the compost through a
¼-inch mesh screen to return the larger pieces of or- Other Composting Methods
ganic material to the pile for further composting next There are several other ways to add organic matter to
batch. your garden and keep kitchen and yard waste out of the
landfill, although some gardeners may not characterize
these methods as composting in the strictest sense of
Compost Use the word. Unlike hot composting, these methods do not
Adding quality compost improves the physical, chemi-
require that you stockpile materials or build a large pile
cal and biological aspects of the soil. The stable organic
all at once. However, except for vermicompost, which
is actually worm castings or manure, materials that are Vermiculture (Composting with Worms)
hot composted produce a superior product that will be Vermiculture is an excellent way to compost in Alaska.
higher in essential plant nutrients and less likely to have For more information, see UAF Cooperative Extension
weed seeds or diseases. Service publication Composting with Worms, HGA-
01020.
Mulching
With mulching, you can add nutrients to your garden There are many ways to compost. Whatever works best
while keeping weeds down and water in. Hay, grass for your situation is the best method to use. Composting
clippings, newspaper and cardboard are all effective is an economical solution for making a nutrient-rich soil
mulches. Add mulch around plants or in your paths, amendment to add to your garden as well as a way to
but give plants a few inches of breathing space to limit recycle up to 20 percent of the waste generated in your
disease incidence. home. For more information on composting, see Exten-
sion publication Composting in Alaska, HGA-01027.
Sheet Composting
Sheet composting is also referred to as lasagna garden-
ing, no-till gardening or no-work gardening. Add or-
References
“Compost Calculator.” Green Mountain Technologies.
ganic matter 18 inches deep. Layer bulking agents with
www.compostingtechnology.com/probesandsoftware/
energy materials just like you would in a compost pile,
compostcalc/
but do it directly in your garden space. Sheet compost-
“Compost Fundamentals: Carbon-Nitrogen Relation-
ing can be accelerated by covering the layers with clear
ships.” 2009 web access. Whatcom Co. Composting,
plastic. To transplant, pull mulch away to form a hole
Washington State University, Whatcom Co. Exten-
(insert soil or compost if desired), place the plant in the
sion.
hole and pack the mulch back around its roots.
“Home Composting”. Cornell Waste Management In-
For more detailed information on sheet composting, stitute. 2009 web access. http://cwmi.css.cornell.edu/
consult Patricia Lanza’s Lasagna Gardening: A New compostbrochure.pdf
Layering System for Bountiful Gardens: No Digging, Lanza, Patricia. 1998. Lasagna Gardening: A New
No Tilling, No Weeding, No Kidding! Layering System for Bountiful Gardens: No Dig-
ging, No Tilling, No Weeding, No Kidding! Emmaus,
Cold and Slow Pa.:Rodale Press.
Cold, or slow, composting is recommended if you have Richard, T. and N. Trautmann. 2009 web access. C/N
only small amounts of fresh material available at a time. Ratio. Cornell Composting: Science and Engineering,
To make a cold compost heap, simply pile together Cornell University.
your nonwoody yard wastes and kitchen scraps and let Rynk, R. et al. 1992. On-Farm Composting Handbook.
them sit for two to three years. Place fresh wastes in the NRAES-54, Natural Resource, Agriculture, and Engi-
middle of the pile to discourage pests and increase aera- neering Service.
tion. You can start small and add to your pile gradually, USDA Natural Resources Conservation Service and
but do not add weeds that have gone to seed or diseased Fairbanks Soil and Water Conservation District. 2005.
plants. Composting Dog Waste.

For additional information, contact your local Cooperative Extension Service or Heidi Rader, Extension Faculty,
Agriculture and Horticulture, with the Tanana Chiefs Conference Federally Recognized Tribes Extension Program, at
907-452-8251, ext. 3477 or heidi.rader@tananachiefs.org. Reviewed by Thomas R. Jahns, Jeff Smeenk, Michele Hébert
and Stephen Brown, Extension Faculty, Agriculture and Horticulture, in 2010.

Visit the Cooperative Extension Service website at

www.uaf.edu/ces or call 1-877-520-5211

351/9-78/WV/3000 Reprinted March 2011

America's Arctic University

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