How To Build A Soilarium
What if we could break down composting for kids so they could see it happening with their own little eyes on a kid-sized scale? Wouldn’t that be fun?
We’ve created a simple sustainability science experiment for kids to learn how to build a soilarium. A soilarium is a clear container packed with composting ingredients to make a loamy soil amendment that kids can use as their own little science laboratory. Read on for instructions and a downloadable workbook to teach kids how to conduct their own composting experiment by building a soilarium.

Gather up some garbage. It’s time to turn that trash into garden gold.
Composting, or nature’s recycling system, is a pretty amazing and effective way that nature uses to continue the cycle of life. Instead of tossing our trash into a landfill to languish for centuries, organic waste recycling turns food waste, yard waste, and just about any organic matter into a nutrient-rich amendment for soil to grow new plants and feed existing organisms that reside in the ground.
The precise science of composting can feel complex and overwhelming if we really dig into the nitty-gritty. Ignore all that for now. We don’t have to understand all the complicated chemistry of decomposition to appreciate the importance of composting and do it ourselves.




We’ve created the following soilarium science experiment for kids to teach them how to build a soilarium and use their scientist skills to observe the process of composting at home without getting tangled in all the complex science.
You can try this experiment at home or share it with a group. Jess, co-founder of RGK, and I hosted a class at the local library to share this experiment with kids in the community. This can be a great lesson for teachers to incorporate into science class at school too.
Ready to Download The Soilarium Activity Workbook?
If you’re interested in more educational kids’ composting material, we’ve also shared a simple activity that covers the basics of composting for kids. That activity shows young learners how to sort items for compost, recycling, and trash They practice classifying items as greens, browns, recyclable materials, or trash. It’s a great introduction to understanding the materials they need to make the soilarium.


How To Build A Soilarium For Kids
To start building a soilarium, gather up the following materials.
Materials To Build A Soilarium (per person)
- clear, plastic 2L bottle or glass jar w/lid
- vegetable and fruit scraps, cut into small pieces (about 2 cups)
- shredded newspaper or brown paper (about 2 cups)
- soil (can use combination of dirt, soil, and compost) – about 4 cups
- leaves or grass clippings
Tools To Build A Soilarium (shared)
- kitchen scissors or small knife
- permanent marker
- if using a plastic bottle, you’ll need a razor knife, a small piece of aluminum foil per bottle and a pencil
- if using a glass bottle, you’ll need a hammer and a nail
- spray bottle of water

We’ve included the full instructions below for you to follow. We’ve also prepared a downloadable activity packet to help young learners get the most out of this composting experiment. We include printable instructions and a material list as well as discussion questions about the sustainability science experiment.
The workbook includes opportunities for kids to observe and reflect on the changes in the soilarium over time. Your young learners can practice their scientific observation and critical thinking skills to make the most of this experiment as a STEM activity for youngsters.
Science Video Tutorial of How to Build a Soilarium
Here is a short science video tutorial to walk you through the simple steps of how to build a soilarium. While you’re watching, be sure to like and subscribe to our co-founder’s YouTube channel, Thoughtfully Sustainable, to receive updates on our latest tutorials to assist you in raising responsible global citizens.


If you try this out, we’d love to hear how it goes. Tag us @RaisingGlobalKidizens on Instagram or Pinterest to show us how it went. Also, be sure to follow us on Pinterest for more activities like this! We’re creating new sustainability activities for kids regularly, and we share them all on Pinterest!



How To Build A Soilarium
Make a simple soilarium with repurposed materials to learn more about and observe the process of composting as a fun and educational sustainability science experiment for kids. Be sure to download the free corresponding printable to learn even more from the activity.
Materials
- clear, plastic 2L bottle or glass jar w/lid
- vegetable and fruit scraps, cut into small pieces (about 2 cups)
- shredded newspaper or brown paper (about 2 cups)
- soil (can use combination of dirt, soil, and compost) - about 4 cups
- leaves or grass clippings
Tools
- kitchen scissors or small knife
- permanent marker
- if using a plastic bottle, you'll need a razor knife, a small piece of aluminum foil per bottle and a pencil
- if using a glass bottle, you'll need a hammer and a nail
- spray bottle of water
Instructions
- If using a plastic bottle, have an adult cut off the neck of the bottle with a razor knife.
- Create layers in your bottle or jar in the following order: soil, food scraps, shredded paper, leaves/grass.
- Spray each layer with water as you go, repeat the layers until the container is full.
- Mark the top of the layers by drawing a line with a permanent marker on your container. Write the date next to the line.
- If using a plastic bottle, use a pencil to poke holes in a piece of aluminum foil and use it as a lid to cover the top of the bottle.
- If using a glass jar, poke holes in the lid with a hammer and nail.
- Place your soilarium in a sunny, warm spot inside or outside.
- Each week for ~8-10 weeks, draw a line to mark the new height of the container's contents.
- Keep damp by spraying with water. To increase air circulation in the container, you may want to stir the contents 1-2 times per week.
If You Like This Post About How To Build A Soilarium, You Might Also Like
8 Ways To Get Kids Excited About Composting