How to Make Compost
Don't throw away those kitchen scraps! Turn them into lush, organic soil for your garden. Yard trimmings and food waste together make up around one quarter of the U.S. municipal solid waste stream. By using these materials to make compost, you get chemical-free fertilizer for your garden, you save money used to purchase mulch and fertilizers, you decrease demand for scarce landfill space, and you reduce greenhouse gases associated with transportation and processing of waste. Composting is a cheap, easy, and hygienic method of converting your kitchen and garden waste into a clean-smelling material that serves as a soil conditioner or surface mulch. Properly controlled, compost is a dark, crumbly fertilizer with a pleasant, earthy smell. Compost serves a dual purpose by returning nutrients to the soil and improving soil structure to increase its water holding capacity. Composting is nothing new - the basic techniques have been used for about 4000 years, while chemical fertilizers have only been widely available for around a century.
What do you need? Composting is simple - you need only a couple of things to get started:
What do you feed your composter? Most organic materials which decompose readily are suitable for use in a composter. Smaller pieces will breakdown faster. Put the following materials in your composter:
- for traditional composting, you need a medium or large composter to be located in your lawn or garden and a compost pail for collecting scraps in your kitchen
- for the high-tech route, purchase a NatureMill all-in-one composting system (available in basic and pro models) that combines the kitchen collection with the compost generation
Do not put the following in your composter:
- garden waste: grass cuttings, non-woody garden prunings, leaves, and flowers
- kitchen waste: vegetable peelings, leaves and stalks, fruit peelings and cores, cooked table scraps, tea leaves, coffee grounds,
egg shells and bread
- herbivore manure (e.g., from horses, cows, sheep, goats, bats, ducks, pigeons, and any other vegetarian animal)
- Browns: small amounts of shredded newspaper, paper tissues, wood fire ash, sawdust, vacuum dust, and dryer lint
What happens in the composter?When your kitchen scraps and garden waste are combined with a healthy mix of air and moisture, naturally occurring micro-organisms start to feed. They generate heat, and the composting environment heats up to around 120-140 degrees. At this temperature, seeds break down and insects cannot breed. The resulting products from the process are soil-enriching compost, carbon dioxide, water, and heat.
- meat or fish scraps
- weeds or diseased plants
- plants sprayed with herbicide
- large branches (unless chipped or chopped up)
- cat or dog droppings
- large amounts of pine needles (which are acidic)
- fats, oils, and dairy products
- anything else which doesn't decompose (e.g., plastics, glass, or metals)
Organic waste left sitting in a pile will slowly degrade, but the process takes many weeks. Fast or "active" composting can be completed in 2 to 6 weeks. The key to fast composting is regular turning and mixing of the composting materials, ensuring sufficient moisture, and maintaining a carbon-to-nitrogen (C:N) ratio in a range of 25-30 to 1 (i.e., you should have around 28 times as much carbon as nitrogen). Browns such as dried leaves, dried grass, and newspaper are good sources of carbon. Greens such as vegetable scraps, tea, coffee, and fresh grass clippings are good sources of nitrogen. You can also boost nitrogen levels by adding blood meal or bone meal to your composting.
Troubleshooting problems with your compost
Using your compost
- Too dry? Just add water and turn the compost.
- Too wet? Add sawdust or newspaper scraps and turn the compost.
- Not heating? Your compost probably needs nitrogen. Add vegetable scraps or bone meal and turn the compost.
- Fly or insect breeding? If your compost is "cooking" properly, it will deter pests. Make sure the compost is hot in the center and turn it regularly.
- Unpleasant smell? The compost will release odor when turned. To reduce compost odors it helps to keep the compost damp (but not wet).
- Too slow? You can speed up the composting process by adding an anaerobic bacteria accelerator, like our Sun-Mar Compost Swift.
To use the compost, mix it with the soil in vegetable or flower beds. Or use as a surface mulch on beds or top dressing for lawns. Chemical fertilizer alone cannot match nutrient-rich, homemade compost. Compost boosts nutrient levels in the soil, saves trips to the garbage can, and reduces garbage output significantly. And your healthy, chemical-free flowers, fruit and vegetables are a most welcome bonus. Even if you can't use all of the compost on your own garden, it will almost certainly be welcomed by any "green-thumbed" neighbor.
For more info on composting, check out the U.S. EPA's website.