Compost Cake

Get your hands dirty and discover how to make compost to grow your own produce!


Find out about soil health, and make your own Compost Cake.

Healthy Soil

Healthy soil provides the means for plants to grow, which also helps to create the oxygen we breathe and clean the water we drink.  It is vital to successful farming and producing the food we need to eat.

Healthy soil is also part of the fight to protect us from the Climate emergency. It can store carbon, locking in greenhouse gases and stopping them from being released into the atmosphere, and helping to prevent flooding.

Only ‘living’ things can have health, so seeing soil as a living ecosystem reflects a fundamental shift in the way we care for our soils. Soil is teeming with billions of bacteria, fungi, and other microbes that are the foundation of an ecosystem. Adding compost to our soil can be a key part of developing this ecosystem and ensuring it is healthy and full of life.


Everything that has been alive will decompose. Decomposed matter can provide nutrients for new things to grow. This vital nutrient cycle is helped along by fungi, minibeasts and other organisms.

Let’s build a compost cake to see this in action!

A healthy compost needs a mix of  ‘browns’ (carbon-rich materials such as dead plants, leaves, or straw), ‘greens’ (nitrogen-rich materials such as grass clippings, fresh plant matter, or food scraps), soil or old compost, and moisture.

Making your compost cake

  1. Take a cardboard box, punch a few small holes in each of the sides for ventilation.
  2. Layer the bottom with stalky brown material to allow drainage,
  3. Cover with a layer of greens,
  4. Cover with a layer of soil,
  5. Add a sprinkle of water.
  6. Repeat the layers until you reach the top of the box.
  7. Store the box outside in sheltered spot, keeping it moist but not too wet.

After several weeks, check back and see what decomposition has started. What bugs or fungi can you see? If you can, record the temperature of your compost cake each week – over time it should heat up to around 70°C and then start to cool down. Heat is being produced by the activity of microorganisms breaking down the materials in the pile. You could look at samples of the compost with a lens or microscope. When you have usable compost, you could use this to grow your own food to share or use on camp.

Make a Compost Pile

If you have space for a full compost pile you can use the same method to build one.

  1. Choose where you will create your permanent compost area – Ideally this needs to be at least one meter square.
  2. Use forks to loosen the ground where the pile will be.
  3. Layer browns, greens, and soil repeatedly until the pile is at least 1m tall. Brown and green layers should be 10-15 cm thick; soil layers should be 3-5 cm thick. Remember to water each layer as it is added to the pile.
  4. As you build up the pile, make sure you keep it in shape and keep the corners as square as possible so that the pile doesn’t collapse and lose its heat.

Take it Further

This activity has been adapted from resources created by Kiss The Ground – visit their website for more information and activities about the carbon cycle and improving the soil.

If you enjoyed this then why not try making seedbombs or do a nature survey of an area near you.


Climate & Ecological Emergency

This is one of our collection of activities that will help you to better understand the climate and ecological crisis and our part in it, as well as supporting you to raise your voice in calling for action to be taken against it.

Activities & Resources

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