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Compost adds diversity to the soil that's great for gardens

Food is the largest single source of waste in the United States. According to the U.S. Environmental Protection Agency, 21 percent of what goes into municipal landfills is made up of food — more than plastic or paper.

Food waste tipped the scale at 35 million tons in 2012. This makes a pretty strong reason to compost.

However, composting is not just about reducing rotting food in landfills. Compost adds to the diversity in the soil, making it one of the best things you can do for your garden. It adds organic material, which gives the soil a better holding capacity and slowly feeds plants.

Composting can be as simple as making a pile of rotting organic materials or as complex as using a three-tier worm composter. However, the basic methods of all composting are pretty simple.

First, your composter needs food, air and water.

Food for the compost pile is referred to as “browns” and “greens.” Greens are the nitrogen-containing organic materials such as grass, coffee grounds and most food waste. The greens collect and hold nitrogen from the soil, and as they break down, they release it.

Browns contain carbon, which is the major component in soil building. Browns include leaves, cardboard and straw. 

As with humans, a proper diet keeps your compost pile healthy. A mix of 75 percent browns and 25 percent greens is ideal.

Learning to compost well takes a little work, and a little feeling and a little smelling to check on the progress:

  • If it stinks, it might be too wet. Add some dry browns to the pile and air it out by turning it.
  • If it is not composting, it may be too dry. Turn the pile while adding some water.
  • The smaller you cut things up before putting them in the pile, the faster they will compost.
  • Keep meat, bones and oils out of your compost pile.

Air helps your compost decompose faster. If you are maintaining a pile or bin, it’s important to turn your pile (move around the material) regularly and make sure it is properly ventilated. If you have a spinning composter, get into the habit of spinning it weekly or any time you add material.

The last requirement is water. Too much water will drown all the organisms that help break down the organic material. Too little, and your pile will not break down.

To tell if your pile is the proper dampness, grab a handful. It should feel like a wrung-out sponge. If it’s too dry, water it; if it’s too wet, turn it and add dry, brown materials.

As you fill your composter, layer the material in alternating browns and greens.

Since most of your food waste will be greens, it’s a good idea to store some brown material near the composter to top off the green material. So, save some leaves to help you through the winter.

Now that we know what your composter needs, let’s think about what kind of composter to use.

One option for outdoor composting is to purchase or make a spinning composter.

This is my least favorite type, personally, and most people I know who have used them agreed.

Drawbacks include size (they tend to be on the small side); the frequency that you must turn or aerate the compost (it can be difficult to turn when it’s full); and the fact that it’s totally enclosed means it has no access to worms and other natural factors that aid composting.

They do make it easy to get started, though, so the store-bought variety can be a good option for those new to composting.

If you have no space outside to compost, try an indoor worm composter. You can either buy a kit or make your own. Worm composters requirements the same food sources, with the exception of items such as citrus or pineapple, which are too acidic in a closed system.

You can to find more information and directions on how to put an indoor worm composter together online. The local Purdue Extension website has some good tips.

I prefer to build my own composters and, in fact, have built several. You can make these composters of pallets, blocks or wood. You can get plenty of tips online to build a nice one — Family Handyman has a good how-to for a three-bin system.

Size does matter. A minimum of 3-by-3-by-3 feet is necessary for compost to heat up enough to kill off seeds and bad fungus. 

I enjoy a three-bin system. The first bin is the start point. Once that bin is full, its contents must be moved to the second bin. As the pile begins to decompose and turns to compost, it moves to bin 3. To prevent non-decomposed material from going into the final bin, there is a screen to catch big chunks.


Composting goes through three basic phases, according to Cornell University:

  • First is the moderate-temperature phase (mesophilic), which lasts a couple of days.
  • Next is the high-temperature phase (thermophilic), which can last from a few days to several months. This is the phase where the micro-organisms do most of the work.
  • Finally, a several-month cooling and maturation phase occurs. This is when the earthworms begin their magic. As the pile cools, the compost is considered finished and is ready to go on the garden.

Compost can be used like fertilizer to top dress a garden (about an inch of compost). In raised beds, mix it with about 20 percent top soil.

Composting of all types can be simple and it has the added benefit of providing free fertilizer for your garden while reducing waste.

Check out the Grassroots Organics class at the Unity Gardens Growing Summit this weekend, March 20-22, for more information on composting — we’ll even learn how to make compost tea.

For more tips and stories about backyard gardening from Mitchel Yaciw, subscribe to the Growing With Unity email newsletter.

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