Composting in the Fall

Cut down on organic landfill waste by turning it into nutritious ingredients for next year’s garden.

Brick Ends Compost is like "black gold".

Backyard composting is a popular and easy way to get the most out of your garden and kitchen waste throughout the year. 

Many people think it’s an activity relegated to the warmer months, or that you need to carefully time your composting to match up with the growing season. But composting can occur year round. With the abundance of leftover organic matter at this time of year, fall is actually a great time for composters, whether you’re seasoned or just starting out.

A lot of people might look at a pile of compost and think, “well, it’s just some dirt.” and while they’re not technically wrong, compost differs from your average garden soil in a few key ways. Soil is the dirt from the ground, typically mineral-rich and varied in consistency. Compost is essentially the remnants of organic material that has been allowed to decompose, along with all the bacteria colonies that helped decompose it*. It’s nature’s way of recycling matter into something plants can use to grow. 

Compost can be added to soil in order to enrich the nutritional content, improve moisture retention, and provide structure for roots. The combined powers of soil and compost make for ideal conditions to grow all kinds of plants. The nourishment these plants get are converted in turn to nutrition for us!

The combination of leftover garden detritus, leaf litter, grass cuttings, and temperature fluctuations all contribute towards a healthy environment to create excellent compost. Not to mention, a hot compost pile can turn scraps into compost in as little as six weeks*

Late summer while the weather is still warm is a good time to start planning out a compost pile, since you’ll be anticipating lots of garden waste and other useful materials for composting later on. Plus, if you have an established pile by the time leaves really start to shed, your compost will be better balanced than if you were to use mulched up leaves as your primary ingredient. If you start off with good organic material in the fall, by next spring you’ll have nutritious compost to add to garden beds, containers, and dressing for greener lawns.

If you’re interested in composting your household organic waste, there are lots of different ways to do so. Many towns nowadays have compost programs for saved kitchen waste and yard clippings. In fact, Black Earth Compost sources kitchen and yard waste from Eastern Massachusetts and Rhode Island, and those who participate in the program are entitled to a free bag of compost each spring. This is a great way to make sure you’re recycling all that good surplus energy from unused organic matter. By contrast, backyard composting does not involve any yearly subscriptions, only a bit of shoveling here and there and a dedicated space. If you don’t compost yourself, and would be interested in starting your own pile from scratch, here are some basic directions to get you on the right track.

Number 1. Acquire a compost bin. This can be a length of hardware cloth, staked around an area about three feet in diameter. There are numerous ways of creating a compost pile, from weaving together fallen branches to constructing your own tumbling barrel. It’s a good idea to reinforce your bin, especially if you live in a dense neighborhood. Many cities require compost bins to be rodent-proof*, often using specialized containers. Make sure to check with local regulations!

Speaking of animals, it’s important to be aware of what’s happening on a microscopic level in your compost pile. The bacteria and microorganisms that turn a pile of leaves and vegetable peels into compost are living creatures that need the right conditions to be healthy and happy. The four main things microbes need are carbon, for energy, nitrogen, for protein, water, for moisture, and oxygen, for breathing*. This is not that different from the needs of any other organism. Your compost pile, essentially, is alive and will get hungry and thirsty, soggy or too cold depending on the day. However, it’s also quite forgiving of mistakes and most things can be remedied by simply adding more good organic matter and a few good turns with a shovel.

Number 2. What to add (and not to add) to your pile. Pretty much any compost bin will start with layering organic material. A good way to start off is with spoiled hay or straw, left to sit outside until it’s gone gray*. Fresh hay requires a lot of nitrogen in order to decay and should only be used sparingly. Plus, something loose like weathered hay helps with airflow when placed at the bottom of your pile. Remember your “browns” (high in carbon) and “greens” (high in nitrogen) when layering, as you need both to contribute to a successful compost pile. Kitchen scraps should be buried in the center of the pile so as not to attract pests. Sprinkle soil over every foot or so. For smaller piles, it may be helpful to add an activator, such as Espoma Organic Compost Starter. This introduces colonies of active microbes. Piles 3 feet wide by 3 feet high provide the necessary heat insulation to speed up the process. Don’t worry if your pile is smaller than that, though. Nature finds a way, and you will get compost eventually.

Carbon to nitrogen ratio should be about 30 parts to 1*. So basically, you should be putting in much more browns than greens to keep the best ratio of decomposition going and make sure everything composts evenly. If your nitrogen levels are too high, the excess nitrogen evaporates into the air and will make your compost pile smell. If there’s too much carbon, it will take much longer to compost.

Number 3. Aerate! Make sure the structure of your pile is such that you can get proper airflow to parts of your pile. This prevents odors and conditions for anaerobic bacteria to grow, which makes for smelly and pest-attracting piles. Another important aspect of keeping a compost pile is making sure to turn the pile regularly. This accelerates decomposition. If you have a large pile, turning could get quite tedious and many choose to let their compost piles decay naturally. Without turning, a pile can take a year to fully compost.

Though fall leaves are an abundant and useful ingredient, leaves shouldn’t be added all at once because they tend to smother whatever’s underneath. Better that you mulch fallen leaves directly into the soil with a mower, and use the rest of your dry leaves as a layering element to complement the kitchen scraps you’ll be putting in. That way you’re not adding too much at once.

Number 4. Moisture. Don’t be fooled by a damp outer layer of your compost pile. Moisture doesn’t always reach the center, and turning helps ensure that water gets through to every layer of matter in the pile. Poking holes with a stick before watering the pile also helps. Dry piles don’t hold temperature as well and so are not as stable in terms of microbial activity. Compost that is too wet, however, will smell bad. If there’s too much water, the microbes won’t get enough air to breathe and will be less efficient. This can be fixed by adding more dry matter like wood chips, paper, and cardboard*.

Black Earth Compost sold at the Co-op.

So, how will we know when our compost is done “cooking”? If you can identify ingredients within your pile still, it needs more time to decay. Compost should be dark brown, rich, and moist. If you take a handful and squeeze, you shouldn’t be able to get more than a drop of water out.

If you have been composting all summer, fall is a great time to spread that compost over your garden beds and lawn to amend the soil after the growing season. This replenishes the nutrients in the soil and sets you up for next year. The Co-op sells wonderful compost from Black Earth Compost, Coast of Maine, and Brick Ends, all of which are suitable for spreading out now in your soil and as an inoculant for getting a pile started. Much like making yogurt or sourdough starter, the easiest way to ensure your composting is off to a good start is to begin with a good mix of actual compost.

Once the weather really starts to get cold, composting will naturally become less active of a process than in the summer and fall. Lots of people elect to cover their exposed compost piles in the winter time as insulation, in order to keep the internal temperature of the pile high enough to promote bacteria growth. But this can often have the effect of keeping water out, or trapping air inside and making the pile moldy. It’s okay if your compost pile gets covered in snow over the winter.

Realistically, not much is going to compost in the dead of winter, it's just too cold for the microbes to have much of an appetite. But freezing temperatures also mean that you don't have to worry about odors. Just keep piling organic matter throughout the winter months and leave them to provide that good boost to your compost in the spring.

Backyard composting, no matter how you do it, is an excellent and simple way to recycle household waste and also take care of your garden. Fall is definitely a clean-up season, but getting a compost pile started now is like making a promise for next spring. Knowing that the nutrients you saved will go on to feed your flowers and vegetables is part of the year-long cycle of work and reward.

Further Reading:

Campbell, Stu. Let It Rot!: the Gardener's Guide to Composting. Storey Communications, Inc., 1975.

Home Composting Brochure: Cornell Waste Management Institute

How Long Does Compost Take to Break Down?

Composting Brochure:

Compost Chemistry - Cornell Composting

Monitoring Compost Moisture - Cornell Composting