Curriculum / For Teachers / Grow

Compost Pile Food Chain

Students learn about decomposition by making a compost pile.

Compost Pile Food Chain

· It is dark brown and looks and smells like soil

· Is composed of nonrecognizable ingredients

· Has an earthy humus-like odor


· To fully encompass the concept of a food chain, students can sketch a diagram that shows the full cycle of a banana that they ate for lunch that day. Have them identify the producers, consumers, and decomposers in this sketch.

· Turning your pile with a fork or tumbler aerates the pile to help bacteria work faster. Turn the pile inside out every few days and have ready compost in as little as 1-2 months. Leave it alone for ready compost in 6-12 months.

· In this lesson, teach kids the concept of dividing what they eat. Have them separate out what is recycled, compostable, and trash after lunch. Maintain a small classroom compost bucket that is brought out to the compost pile at the end of the day.

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A compost pile is an ideal environment to observe the process of decomposition. Organisms in the food chain include microscopic fungi, protozoa, bacteria and more.

Larger organisms include mites, earthworms, spiders, and snails. All of these organisms can be classified as decomposers who are responsible for breaking down dead organic material and cycling it back into nutrients such as nitrogen and phosphorous for living things.

The type of decomposition that occurs in a healthy compost pile is aerobic (as opposed to anaerobic), meaning the bacteria use oxygen to feed on the organic matter. That is why it is important to aerate your compost pile with a pitchfork or shovel to keep it active.

Plants grown in good soil grow faster, produce more fruits and vegetables, and resist pests and diseases. Good soil is at the heart of all gardening.



· Students build a compost pile

· Students learn the concept of decomposition in the way it relates to the food chain



LS1.C: Organization for matter and energy flow in organisms.

Food provides animals with the materials and energy they need for body repair, growth, warmth and motion; Plants acquire material for growth chiefly from air, water, and matter and obtain energy from sunlight, which is used to maintain conditions necessary for survival.

4.MD.A.1: Measurement & Data

Solve problems involving measurement and conversion of measurements. Know relative sizes of measurement units within one system of units including km, m, cm; kg, g; lb, oz.; l, ml; hr, min, sec.

Within a single system of measurement, express measurements in a larger unit in terms of a smaller unit.



· Green materials/brown materials

· Water

· Several handfuls of cured compost

· Pitchfork

· A constructed bin



Build a simple compost bin, which can be made out of four recycled pallets.



1. Create a base for your pile made of woody browns- like larger sticks and branches- to allow air flow and drainage under the pile.

2. Apply alternate layers of browns and greens about 4-6 inches thick.

3. Between each layer, sprinkle a few handfuls of compost to inoculate the pile with healthy bacteria and moisten with water to the dampness of a wrung-out sponge.

4. Repeat until pile is 3-5 feet high.

5. Keep a layer of browns, such as straw, on top so that the nitrogen doesn’t evaporate.

6. After building your pile, take the stick end of a shovel or a large stick and poke holes through the pile from top to bottom to create airflow.

7. The outside of the pile will not fully decompose. Once the pile has decomposed, sift through it with a heavy-gauge wire screen.



1. What are some foods to feed/avoid feeding the compost pile?

2. Why do we need to aerate the compost pile?

3. What two elements are needed for a perfect compost pile?