Composting 101

Composting is a popular practice for home gardeners especially for those who wish to be more sustainable, practice organic growing methods, or simply save money. Not only can composting help you achieve these goals, but it’s also great for the environment and the soil. Composting allows you to manage your yard/garden waste and kitchen scraps, putting valuable nutrients back in the soil, and keeping this waste out of landfills. It also improves soil quality and acts as an amendment for difficult soils. There are nearly countless options for building a pile, and depending on the amount of compost, it can take minimal time and effort once the pile is built. If you’re on the fence, give it a try–you might just find your new favorite garden task!

Why Should I Compost?

1. The most important benefit of composting is the addition of organic matter to the soil. Organic matter introduces humus (organic materials that have completely decomposed) to the soil, which increases its nutrient holding capacity while adding these nutrients (such as nitrogen, sulfur, and phosphorous) in a form that is available to plants.

2. It increases organism diversity in the soil by giving microorganisms, beneficial bacteria and fungi, and worms the necessary nutrients and habitat to encourage them to breakdown organic materials. These microorganisms can also produce or release chemicals that can help control certain plant diseases.

3. Organic matter acts as an amendment for certain soils. For example, it increases the water holding capacity of sandy soils, thus better enabling roots to absorb water. It also makes nutrients more available to plants in sandy soil. In heavy clay soils, organic matter increases the aeration of the soil—better allowing plant roots to penetrate the soil and increasing drainage of excess water.

When Do I Start?

Now is the perfect time to start a compost pile. While the pile will go dormant as the temperatures drop, fall garden cleanup is a great time to get the process started. As you clean up your yard and gardens to prepare for winter, add the debris and waste to the pile. Once the air temperature reaches 50˚F in the spring the activity will start again. This will help ensure you have compost ready for your spring and summer garden ventures. You can also start a new pile in the spring or early summer for your fall plantings.

How Do I Start?

There are two important considerations when starting a compost pile – where it will be located and how it will be contained. Location is important as you want it to be easily accessible, yet out of the way. A compost pile should be between 1 cubic yard (3 feet tall x 3 feet wide x 3 feet deep) and 5 feet on all sides. This will allow the pile to reach the appropriate temperature, between 140 and 160 ˚F. Ideally, the pile would be close to where you are gathering materials from, as well as close to where you will use the finished compost. The pile should be protected from excess wind to prevent it from drying out too fast. It should get partial sun to help heat it up but avoid putting it in full sun, as this will also cause it to dry out faster. Placing the pile near a water source will make keeping the pile moist easier. You may also want to consider the view from the road or neighbors’ homes, if necessary.

Compost piles can be built out of a range of materials – you may even already have some lying around. It’s important to properly contain the pile, as it not only saves space it will also speed up the composting process, keep the area looking tidy, and can help keep materials from blowing away. It also forces the pile to stay between the 3 and 5 square footprint. This is important because a pile that is too small will not maintain the proper temperature, especially in cooler weather, while a pile that’s too large will restrict the necessary airflow to the center of the pile. Lastly, containing the pile allows the outer layers to act as an insulator, creating higher temperatures in the center, where microorganism activity takes place.

Building the Pile

In an ideal scenario, the material would be kept in a cylindrical or cubical mass. Regardless of what you build the pile out of, be sure there are openings to allow for airflow as well as provide access for adding water and removing the finished product. You can build the pile out of blocks, wood, wire fencing, and more. While the options are nearly endless, here are a few ideas using items you may already have at home.

1. Concrete block or brick
   For this compost pile, you can use cinder blocks or bricks. Lay the bricks or blocks in a 3-sided square. Do not use mortar, and be sure to leave space between the blocks to allow for aeration. The number of bricks or blocks needed will depend on how big you want the pile as well as the size of the blocks you are using. Material can be turned directly in the bin. You can also make a 3-bin unit, discussed below. As a note, this method is not stable, so use caution if placing in an area where kids will be playing or have easy access.

2. Wire fencing or snow fencing
   With this method, you will create a cylindrical bin that’s 4-5’ in diameter and height. Fasten the ends together with wire or chain clips. When it comes time to turn the pile (more info on this below), simply undo the wire/clips and move the structure. Reshape the cylinder and turn the compost into it in the new location.

3. Barrel
   You can easily repurpose a 55-gallon drum to use as a composter – just be sure you have a lid that attaches securely. Drill ½” holes down the length of the barrel – 6-9 rows should be sufficient. Be sure to only fill the drum ¾ of the way with material. When it’s time to turn the pile, simply drop the drum to its side and roll it a few times before propping it back up. This is a great way to recycle old drums – just be sure they weren’t previously used for toxic substances.

4. Wood and wire
   This is a great option for smaller spaces and is relatively easy to move. Simply make four frames, minimum of 3x3, out of lumber and hardware cloth or chicken wire, and attach the frames together in a square. One side should be able to open using hinges and a latch, or a similar method. You can use scrap wood and fencing or other lumber – just be sure the wood will not deteriorate throughout the season, especially if you are intending to keep the pile over the winter. This bin can be kept in place throughout the process as it allows access to turn the pile, or it can be moved to another location and have the compost turned into it, much like the wire fencing cylinder.

5. Three-chambered bin
   If you have a lot of material to compost over the course of the garden season and you have plenty of space available, you may want to consider a three-chambered bin. This bin can be built out of a variety of materials – cinder blocks or bricks, lumber, repurposed pallets, etc. Again, just be sure that whatever materials you use allow for airflow. With a three-chambered bin, you will create 3 bins, side-by-side, that are each between 3 and 5 cubic feet. This creates an assembly line for your compost. Begin by putting your compost in the first bin for 3-5 weeks. Then, turn it into the middle bin for 4-7 weeks. During this time, you can begin a new pile in the first bin. Finally, turn the material in the middle bin into the last bin to finish, then continue the cycle. By creating an assembly line, the three-chambered bin can be efficient and provide compost for an extended period. If built well, it can also be quite durable.

What Should I Compost?

You can use a variety of materials from your yard or garden. Many kitchen scraps can be composted as well. The compost pile should be a mix of “green” and “brown” materials. Green materials include fresh leaves (make sure they are not wet), weeds, and cuttings; fruit and vegetables peels and other scraps; manure (check local and county codes to ensure this is allowed); and coffee grounds and tea bags. Brown materials include dry leaves, dead weeds, eggshells, woodchips, and straw. Regardless of what you’re adding to the pile, it is recommended to shred all materials before adding them to the pile, if possible. This will help speed up the process as it allows the microorganisms to work faster. It also makes turning and/or moving the pile easier.

Certain materials that should never be composted include: meat, bones, fatty foods and oils, dairy products such as cheese, weeds that readily propagate through root or stem cuttings, plant materials that are clearly diseased or infected with insects (especially if you are unsure of the disease or if the disease readily spreads), and human or pet waste. You also want to be careful if adding lawn clippings as they can pack down and restrict airflow. It is considered safe to leave grass clippings in the yard to decompose, assuming you mow regularly and only remove 1/3 of the blade length each time. If you decide to compost grass clippings, mix them with other materials before composting.

How Much Do I Add?

Ideally, a compost pile will have a carbon to nitrogen ratio of 25-30:1. A good rule of thumb is to layer 6” of brown material, followed by 2” of green material, then topped with 2” of soil or finished compost to introduce decomposers and help prevent odors. “Brown” materials contain more carbon than nitrogen and will have a higher C/N ratio than green materials. While a compost pile with a lower C/N ratio (higher green material content) will decompose faster, a lot of the nitrogen used by decomposers for energy will be lost quickly, therefore needing to be replenished. On the flip side, if too much brown material is added, the pile will decompose slowly. If this is the case, you can add additional nitrogen such as a grow-formula fertilizer or other green materials. If allowed in your area, manure can be added as a source of nitrogen as well.

As a note, try to avoid adding fresh materials to the pile once the process has started. If you have a minimal amount of new material to add, you can do so only when you turn the pile. Your best bet is to collect the materials in bags or another container and start a new pile once you have enough.

Maintaining the Pile

A well-managed compost pile will take about three to four months to decompose. The pile should be turned frequently for the first three to four weeks, then once or twice for the remaining months. Turning is important because it incorporates the outer materials into the center where they will decompose. It also creates air spaces, providing the microorganisms with the required oxygen, and helps eliminate odors due to improper moisture levels. You should regularly check the moisture levels in the pile. This can be done by sticking your hand in the pile and squeezing the material at several depths. Ideally, the pile should be kept moist like a damp rag. If the pile is getting dry, add water then turn the pile to ensure the water is spread throughout. Keep a close eye on moisture levels during the rainy season. A pile that is too wet will not allow enough oxygen to permeate the pile. Oxygen is an important part of the process as microorganisms require oxygen to do their job. Too much moisture can also cause the production of compounds that are toxic to some plants. If the pile is getting too wet, consider covering it with a compost blanket, which allows for air flow but helps control moisture levels. Do not cover the pile with plastic or a tarp, as this will prevent air flow.

Using the Compost

Compost is ready to use when the pile is no longer hot in the center and the material is dark brown, smells like fresh dirt, and crumbles when squeezed. Once the compost is done, you’re ready to add the finished product. Mix 1-2 inches of compost into the top 6-8 inches of topsoil. You can also use finished compost in potting and germination mixtures to replace peat moss. If you wish to use compost in your germination mix, allow the compost to sit for an extra month or two to ensure the microorganisms have left the pile or died as they can attack and damage the seedling roots. Screen the compost through hardware cloth with ½” squares to get rid of any clumps.

Composting is a great way to use the plant material, yard waste, and kitchen scraps you likely already have. While it may seem like a lot to handle, starting a compost pile can be as simple as purchasing a composter online or building a basic container out of scrap materials you have lying around. Like most other aspects of gardening, composting can be a process of experimentation, trial, and error. Most master gardener extension programs and local universities have great resources if you feel stuck. We are always happy to answer your questions as well! Give it a go this fall or next spring and you might just be surprised by how easy and rewarding it can be!

Author: Ashley W.