Hot Composting Guide: The Faster Way To Make Rich, Organic Compost At Home

Composting is an essential skill to learn for any serious gardener. Known affectionately as black gold, compost is a rich, nutritious soil improver and costs little to make besides time. As well as benefitting plants, it's a great way to reduce food and garden waste, as these can be added to the compost heap, where they will decompose over several months. But not all gardeners are patient enough to wait that long. This is where hot composting comes in.

When learning how to compost at home, most gardeners will practice the traditional "cold" method of layering up a bin or pile with the right mix of compost greens and browns, turning the heap occasionally, and waiting until it's ready to use. It's a slow, steady process that gives reliable results. Hot composting uses many of the same ideas but refines the process to speed up development. Here’s what you need to know.

What is Hot Composting?

Compost is created when microorganisms break down organic matter. The microbes create heat as they do this, so all compost piles are warm to a certain degree. Hot composting is a specific method for creating compost that optimizes microbial activity, resulting in quicker breakdown of organic materials.

Optimizing the activity of these compost bacteria depends on achieving a minimum temperature. Hot composting happens at higher temperatures than standard composting, hence the name.

What Are the Pros and Cons of Hot Composting?

One of the biggest advantages of hot composting is the speed of the process. By optimizing microbial activity, you can produce usable compost in much less time than with the standard cool compost method. While traditional composting takes six to 12 months, hot composting gets results in a matter of weeks if you do it right.

Another important advantage of hot composting is weed and pathogen control. The high temperatures in the compost pile kill most weed seeds and pathogens that can cause disease.

The primary disadvantage of hot composting is that it requires more effort. Cool composting is also known as passive composting. You mostly leave it alone and let it decompose. The hot method requires more turning, temperature checks, and other factors, like moisture control.

Can I Make Hot Compost Indoors?

Technically, you can make hot compost inside, but keep in mind that you need a larger size bin than for standard compost. Other potential issues could be attracting pests and unpleasant smells. So, hot compost is best created outside.

However, there are other ways to compost indoors. Electric composters offer gardeners a way of recycling kitchen scraps on the countertop. While most models apply high heat to dehydrate the food waste, the best electric composters break it down at a lower temperature and add bacteria to the process. One such model is the Reencle electric composter, available in the Gardening Know How Shop, which supports microbial activity and produces plantable compost in just three weeks.

What Do I Need to Start Hot Composting?

You need a few key ingredients and tools to start hot composting in your garden. In addition, it's vital to learn what can be composted.

• You need a compost bin or area for a compost pile, approximately 3 or 4 feet (0.9 to 1.2m) on each side
• A thermometer for checking the temperature of the pile
• Green (nitrogen-rich) waste, including grass clippings, plant trimmings, coffee grounds, tea bags, and fruit and vegetable scraps
• Brown (carbon-rich) waste, including dry leaves and other yard waste, paper and cardboard, straw, hay, untreated sawdust, and small twigs and branches

How to Start a Hot Compost Pile

Once you have all the materials, the next step is to chop down the organic matter into small pieces. This speeds up the composting process. The easiest way to do this is to run over the materials with a lawn mower. You can also use hand shears to break down bigger pieces of yard waste. The smaller you can get the pieces, the more successful your hot composting will be.

Next, layer the green and brown waste in the composting bin or area. Start with a bottom layer of larger pieces of plant material, like sticks or straw. This will allow for some airflow in the bottom of the pile. Alternate layers of green and brown waste of equal thickness on top of this base layer.

As you layer the materials, add water. The overall moisture of the pile should be like that of a wrung-out sponge. It should be moist throughout but not dripping wet. Finish with a brown layer to deter flies and other pests.

How to Maintain Hot Compost

Building the hot compost pile is only the beginning. To get good, fast results, you need to maintain the pile’s moisture content and interior temperature. The ideal compost temperature for optimizing microbial activity without killing the microbes is about 130°F (55°C).

Use a thermometer to check the temperature of the pile, ideally every day. You should see the temperature rise to 130. Whenever you notice the temperature change (rising above or going below 130), it’s time to turn the pile. Turning compost will cool the temperature if it’s getting too hot. When the temperature is too cool, turning it will introduce oxygen and restart microbial activity.

Use a garden fork or shovel to turn the material. As you turn it, aim to move some of the material from the outside of the pile to the interior and vice versa. Check the moisture regularly, adding water as needed.

How to Use Hot Compost

Your compost is ready to use when it has a fairly uniform consistency and is dark brown or black. The size of the pile should have reduced by about 60%. The smell of finished compost is earthy. It shouldn’t retain any smell of waste materials.

Use hot compost as you would any other compost. Add it to garden beds to enrich the soil or add it to potted plants to add nutrients.

Common Issues with Hot Compost

Hot composting requires more maintenance and attention to detail than standard composting. There is more room for error. Here are some typical issues and how to fix them:

• Flies in Compost
  You don’t want to attract a bunch of flies with your compost. This usually happens if you leave kitchen scraps on top of the pile. Always bury these under other layers and keep brown waste on the top of the pile.
• The Temperature isn’t Rising
  If the temperature is not getting to the ideal level, you could have a few issues. One is that the pile isn’t big enough. Volume is needed to reach critical temperatures. You may also need more green waste, which is an easy fix. If the pile is too dry, the microbes won’t do their work. Add water to keep it evenly moist.
• Bad Compost Smell
  If you detect a smell of ammonia or rotting, you might be keeping the pile too wet. Another issue could be an excess of green waste. Add dry brown waste to fix these problems.

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