Organic Gardening (Thermal Composting)

Graduation Requirements
Science Laboratory
Field & Cluster
Agriculture Agriculture, Food & Natural Resources
Equipment/Materials Needed

Four wooden pallets or woven wire fencing

Greens (lawn mower clippings, cafeteria waste, garden wastes)

Browns (straw, leaves, wood chips)

Compost Thermometer

Shovel or Pitchfork

compost temp

Our investigation into a sustainable organic gardening process will require the generation of compost. Thermal composting will produce more compost in less time.

Badge Completion Requirements

Thermal Composting

More compost in less time, thermal composting is the answer.

Composting is a topic of growing interest throughout the country. Why composting? There are a number of reasons.

Composting provides a way not only of reducing the amount of waste that needs to be disposed of, but also of converting it into a product that is useful for gardening, landscaping, or house plants.

Composting provides a partial solution to an issue of great concern in many communities. All around the country, landfills are filling up, garbage incineration is becoming increasingly unpopular, and other waste disposal options are becoming ever harder to find.

Composting provides an incredible resource for educational observations and ends with a usable product that helps rebuild depleted soil

The vast bulk of the decomposition work in compost is carried out by microorganisms including fungi, bacteria, and actinomycetes (organisms that resemble fungi but actually are filamentous bacteria). Microbes can be plated for the study of individual species, or their populations can be charted through something as simple as daily temperature measurements.

Under optimal conditions, a compost pile will heat up to temperatures in the range of 50-65°C (120-150°F), caused by the metabolic heat of the microbes. You can see evidence of this when a steamy mist rises from your compost pile as you turn it or dig into it.

At 145 degrees we recommend turning the compost pile in order to prevent the compost pile from becoming anaerobic. When the compost pile becomes anaerobic a new unwanted group of bacteria will dominate the compost leaving it with an ammonia smell. The ammonia smell is the nitrogen that we want to keep being released as a gas into the air.

Good thermally generated compost can be completed in about 30 days.


Discuss what is meant by "greens" and "browns"

Explain the ratio of greens to browns needed for a successful composting pile

Discuss the size requirements for an active thermal compost pile

Explain how temperature is generated and why it's important to track the pile's temperature

Explain the terms; anaerobic and aerobic 




Building and tracking a thermal compost pile


Normal laboratory safety


Four wooden pallets or woven wire fencing

Greens (lawn mower clippings, cafeteria waste, garden wastes)

Browns (straw, leaves, wood chips)

Compost Thermometer

Shovel or Pitchfork



Place a layer of green material about 6 inches thick

Then cover the green material with about 12 inches of brown material

Continue the process until the bin is full

Add water until the entire pile is saturated 

In three days begin checking the temperature of the pile 

Once the temperature raised above 135 degrees Fahrenheit 

Turn the pile over 

Continue this process until the compost pile fails to heat


Please develop and submit a presentation demonstrating your understanding and construction of a thermal composting pile. Continue to evaluate the pile's temperature and condition for 30 days. Please include the above prompts in your presentation.