The State of Large-Scale Compost
by Mary Jasch
Here are three recipes of quality composts produced by two businesses and one county landfill. See how they differ, then read on for the down and dirty.
Compost: Gourmet Style by Ag Choice, Andover, NJ
1 pile each:
Leaves and nuts
Animal bedding with manure (horse, cow, goat, chicken, duck, ostrich)
Supermarket food wastes (veggies, fruit, bread, floral products)
Plant by-products from pharmaceutical companies
Measure moisture content, carbon to nitrogen ratio and other data of each ingredient. Plug data into the computer. Get recipe with exact amount of each ingredient so all finish decomposing together. Fill 12 windrows with 125 cubic yards each of material. Cook at 150 F and cover with a geo-textile mesh that moderates sunlight, moisture, temperature and air, yet keeps out rain to prevent leachate. On breezy, sunny days uncover to dry.
Turn windrows five times/week for the first two weeks, then every few days thereafter. As ingredients decompose and shrink, combine windrows to maintain mass, heat, and the process. Compost is done in eight weeks (summer) to 12 weeks (winter). Put in bags and bring to nurseries and stores or deliver bulk. Compost is accredited by NOFA for use in organic applications.
Compost: All Purpose & Custom by Compsoil, Northfield, CT
1 pile each:
Animal bedding (horse, llama, circus elephant, cow)
Wood chips, saw dust from power line companies
Coffee grinds from Dunkin’ Donuts, Starbucks and local restaurants
Put piles in windrows up to 600 feet long. Cook at 150 F and turn frequently. Test for doneness: pH range of 6-7, temperature below 100 F and other tests as requested.
Compost/Soil Mix (Compsoil)
Mix above compost with soil according to buyer’s specs. Sell in bulk or ready-to-plant 5-gallon pails for $25.
Compost with Worm Castings (Compilizer)
First, grow red worms in moist manure bed in summer and in greenhouse in winter. Feed leaves, grass clippings, manure and food scraps. Check that fresh cattle and horse manure do not have de-worming in it. Look to see that everything’s digested and all that’s left is the worms and their castings. (Red worms eat their own body weight in food every 48 hours.) Put on a “wheeler-barrow” to sift out castings.
Mix castings with compost as Compilizer and sell in ready-to-plant 5-gallon pails. What’s so great about worm castings? They’re the number two organic fertilizer in the world, owner Russell Wheeler says. Bat guano is number one. Bag castings to sell alone.
Sell worms by the pound ($25-$37) to gardeners and schools. Gardeners either release them into the garden or compost pile, or keep them under their sinks to eat food scraps. “They compost indoors under the sink,” says Wheeler. “You hear them squishing around at night if you have enough of them. Fifteen or 20 pounds will be making some noise.”
Other Custom Composts: mixes for different shrubs and trees, lawn mixes for seeding, leaf compost, manure compost, Compicide – compost tea made from compost pile runoff to spray on lawn or garden, and an organic herbicide from a stronger version. They also hold organic lawn programs, pooh parties, and soon paper made from elephant manure.
Compost: Landfill Specials by Sussex County Municipal Utility Authority, Lafayette, NJ
1 mixed pile:
Leaves collected year round
Grass and yard clippings
Put mix in 10 windrows of varying lengths, 7 feet tall with 14-foot bottoms. Turn windrows more often than State mandate of once/week for the first month, twice/month for the second month, then once/month thereafter. “We go above and beyond,” says Jim Sparnon, solid waste superintendent.
Residents can load their own halfway-humified compost for free or pay SCMUA $18/cubic yard for 3-year old yummy stuff. The landfill also uses the compost onsite to cover slopes and grow grass. The half-done compost has another 6 to 8 months before it’s really done, Sparnon says. He knows it’s done when it looks and smells like soil. In a busy year, they sell out every four months.
So, is there such a thing as good or bad compost? One of the issues during composting is, surprisingly, when is it actually done?
“There’s no easy way to define that,” says Peter Strom, professor of biological waste treatment, Rutgers University. “If you leave it longer it’ll compost more and if you leave it longer it will compost even more. At some point it’s very much like the humus material in soil. At some time before that people usually refer to it as being done.”
Problems arise when using compost that’s not done enough, depending on starting materials, he says. Some can produce compounds toxic to plants. Ammonia is one that can be released, not from leaves, but from other types of compost such as sludge or food waste. When given off as a gas, it can be toxic.
High or low pH can be harmful to plants, too. Ideally, finished compost is near neutral. Materials high in nitrogen, such as grass clippings, food waste and sewage sludge, create a higher pH, Strom adds.
Should buyers bring litmus paper to test the pH? It’s difficult to interpret, warns Strom, because some waste starts off acid, becomes alkaline, then goes back to being neutral. So if you get a neutral reading you might catch it on the way up or down. That’s why it’s difficult for people to agree on simple tests for knowing when compost is done.
For instance, leaves start to rot in the homeowner’s yard before they are collected. They are anaerobic and form acetic acid (as in vinegar). Those acids are biodegradable so once the actual composting starts and becomes aerobic, those materials decompose and the pH becomes neutral. At the same time ammonia gets released. Ammonia is a base and brings the pH up. By the end, if the ammonia’s been stabilized, it becomes neutral again and actually can become acid again if it becomes very stable.
Is good compost made from a lot of ingredients? “There are two things that go into the making of good compost, Strom says. One is the composting process itself and one is the final product. “The final product will be similar if you wait a very, very long time. But since people usually don’t wait that long the product that’s distributed will vary depending on the starting material.”
Is municipal compost with limited sources good? Yes, you get a more varied microbe community in composts with more varied inputs which has additional benefit, says David Lamm, state conservation engineer, Natural Resources Conservation Service, but any compost is good because of the organic matter, an important soil factor. “A lot of the good bugs and microbes that you want are there scattered in the soil anyway. Once the products are there that they need, then they’re going to start to multiply and you’re going to get into that healthy cycle,” he says.
Do microbes live in bagged compost to make it to a gardener’s garden? In dry compost, activity level is low but microbes will revive. If the compost is too wet, it’s anaerobic and microbes might not be there. “But when it’s added back into the soil and it dries a bit, you have all the ingredients for those microbes to come back in. Some are already in the soil but they’re just not as active because optimum conditions are not there. This helps bring it back to optimum conditions and the soil attains a healthier cycle,” Lamm explains.
Russell Wheeler says that right now in Connecticut, as is probably the case in other states, no regulations mandate that ingredients be listed on bagged compost, although Ag Choice does list their ingredients on the bags. Some are made from slaughterhouse scraps or even sewage sludge decomposed with manure and plant materials – and no one is the wiser. He expects that soon that will change, at least in Connecticut, and compost sources will have to be listed.
NJ state law requires nutrient information to be on the bags. Bagged compost requires testing that bulks sales do not.
So, what’s a gardener to do? Use your senses. Compost is considered done if you can’t see any individual leaves, if it’s moist and doesn’t smell, has a soil-like texture and an earthy dark color. Otherwise, a chemical and biological analysis is needed. Beware of dry compost – it might not smell even if it’s not done.
Ag Choice: www.ag-choice.com
Russell Wheeler, Compsoil (860) 283-4776
Natural Resources Conservation Services www.nj.nrcs.usda.gov/
Sussex County Municipal Utilities Authority: www.scmua.org
Strom, P.F. & M.S. Finstein. New Jersey's Manual on Composting Leaves and Management of other Yard Trimmings www.nj.gov/dep/dshw/rrtp/compost/cptitle.htm
New Jersey Department of Environmental Protection
Flower, F.B. & P.F. Strom. Backyard Leaf Composting.
Cooperative Extension Service Publication No. FS074, Cook College, Rutgers Univ., New Brunswick, NJ.
Strom, P.F., J.A. Murphy, & H.W. Indyk. Minimizing Waste Disposal:Grass Clippings.
Rutgers Cooperative Extension Publication
R. Flannery & F.B. Flower. Using Leaf Compost.
Rutgers Cooperative Extension Publication
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published June 04, 2009