Compost is a very forgiving process. There are many "roads to Rome," and no two compost piles are alike. But sometimes things don't seem to be going exactly how you want them to. Here are some common compost concerns and how to handle them. Every composter begins with their own unique blend of compostable materials and expectations. Composting is a dynamic biological process with many variables beyond the materials you are adding. As decomposition proceeds, a number of changes occur in the physical, chemical, and biological characteristics of the compost mix; a change in one parameter can have an effect on all the others. Adding moisture, for example, may increase microbial activity but also has a cooling effect on the pile and may decrease its porosity. Turning will also have a cooling, drying effect, but the added oxygen should follow with a burst of activity.
Monitoring these changes allows you to assess the progress of your compost, identify potential problems, and compare systems. Simple observation of the physical changes that occur during composting is one form of monitoring. Some composting challenges are quite simple and can be solved with a few quick adjustments while others may take more investment and time. Experimentation is just part of the fun! Following are a few common challenges related to composting at home that practitioners might experience.
"My pile smells."
A smelly pile is an anaerobic pile, or a pile lacking oxygen. If compost is too wet or compacted, it will become anaerobic and produce hydrogen sulfide, methane, and other odorous compounds that are hard to ignore. Aerobic, or oxygen-loving, microbes don't create that unpleasant odors that anaerobes, do. Once the pile is depleted of oxygen, the smelly microbes move in. [caption id="attachment_1158" align="alignright" width="177"]
Turning prevents odors and speeds up decomposition by moving materials between inner and outer areas of the bin, preventing the matting of materials like paper and grass clipping[/caption] The simple answer to solving odor problems is to return the pile to an aerobic state. If the carbon-to-nitrogen ratio seems right, and there’s ample “fluff,” it may be too wet. If it’s still producing odors after it has been aerated and dried out a bit, try mixing in some dryer, coarser material to increase porosity. In an outdoor compost pile, turning the pile and mixing in additional high carbon materials such as wood chips should correct the anaerobic condition, although initially the mixing may make the odor even more pronounced. The aerobic bacteria are highly efficient, and once a few changes are made to create conditions more suitable for them, the odor will dissipate.
"I don't have many brown materials but lots of greens like grass clippings and food scraps."
In this situation, traditional backyard composting may not be the best fit. Alternative composting methods include grasscycling of the grass clippings and/or vermicomposting for the food scraps. Grasscycling is an excellent way to improve lawns and divert clippings from the landfill. It may also be time to set up a worm bin! This method of composting involves feeding kitchen scraps and other organic wastes to worms that are kept in an aerated container.
Another option for acquiring carbon-rich (brown) materials is to look just outside your immediate area (i.e., asking your neighbors if you can rake their leaves to use in your compost pile. This may also be a great way to spread the word of composting, and to potentially share this experience with other compost enthusiasts in your community. Other carbon-rich materials include: newspapers, junk mail, toilet paper rolls, cardboard, and egg cartons. Most of these materials can be gathered without leaving your home.
“Sometimes I have too many food scraps or grass clippings, and I can’t incorporate them into my pile right away.”
If you experience spikes in the volume of food scraps, grass clippings, or other strong nitrogen sources--there are several options. If you are using a worm bin and you fear overloading the bin with food, put your food scraps in an airtight container and freeze them until your worms are ready for more. If you think it will only be a day or two before you can use them, the refrigerator is also an option. The same goes for your compost pile. If you feel you have ample greens in the pile already, freeze the scraps and add them after the pile is more broken down. [caption id="attachment_1157" align="alignright" width="185"]
Excess greens can be left out to dry and transition to browns. Materials in a transition stage count as both greens and browns when assessing C:N ratios[/caption] Even if you initially build the pile with a perfect C:N ratio, microbes will consume the nitrogen and carbon at a disproportionate rate, and another addition of greens will give them a needed nitrogen boost a quarter to halfway through the process. Grass that isn’t left on the lawn, used for mulch, or immediately incorporated into the compost pile can be spread out and dried, put back into a storage pile, and added to compost later. Grass clippings or fresh garden materials set aside in a storage pile will lose their nitrogen content over time and will begin transitioning to a more carbon-rich material.
"I have so many leaves; they can't all fit in my pile."
A multi-bin system allows for consistent diversion of materials and production of finished compost. In multi-bin systems, each bin represents a different phase of decomposition[/caption] If you have the room, make a larger, elongated pile, or several smaller piles. You may consider using a three-bin system. You can run your leaves over with the lawnmower to reduce their volume or to use them for mulch. Shredding leaves increases their surface area, but reduces the porosity they offer in the pile. If space is not a concern, leaves and other browns can also be stockpiled until they can be incorporated into a new pile. If none of these options work, be sure to set them out in your green yard waste bin for collection. They'll be composted by El Corazon, Oceanside's commercial composting facility. The previous situations represent some of the most common concerns in composting, but a variety of other questions may arise given the diversity of compostable materials, bins, environments and expectations. Composters develop skills to evaluate compost piles and choose trouble-shooting strategies through experience and experimentation. The senses of sight, touch, and smell are the most valuable tools for assessing the composting process. Fortunately, composting is a very forgiving process!