By: Kelsie Fronheiser, Gene Edwards, Jenny Kraus, Justin Lange
These instructions will help you create your very own eco-column in your home or classroom. An eco-column is a self-sustaining ecosystem on a small scale, made of plastic soda bottles.
This eco-column has 3 chambers: the terrestrial chamber, the decomposition chamber, and the aquatic chamber. The terrestrial layer represents the land habitat including plants and insects (if desired). The decomposition chamber represents a leaf litter habitat, much like a compost pile. The aquatic chamber is a mini freshwater habitat for aquatic plants and even small fish.
All three of these chambers make a “mini-ecosystem” that you can observe at home or in a classroom setting. You can see the interactions between the chambers as you water the plants that grow in the terrestrial chamber and watch the water travel through the decomposition layer all the way to the aquatic habitat below. This project is perfect for those who want to learn about the environment and how it works, which is why it is a great project for students of all ages.
About 60 minutes
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Step 1: Materials & Tools
Required: Where to Obtain
- Exacto knife
- One medium-sized nail: Hardware stores such as Home Depot or Lowes
- Rubber band
- Black Sharpie
- Measuring tape
- 3 clear 2 liter soda bottles and caps (avoid Canada Dry- labels are very hard to get off)
- ~3 cups of aquarium gravel or small rocks: Pet store, creek beds
- 5-6 cups of soil, organic or untreated: Garden stores or garden sections of popular superstores
- Dead organic matter such as leaves, small sticks, dead bark
- Small aquatic plant (hornwort, ludwigia, moneywort, cabomba, myrio, etc.): Pet stores
- Seeds of small plants such as grass, radish, arugula, basil, etc. (these examples are fast-growing): Garden stores, supermarkets
- Untreated tap water or distilled water: Leave tap water sitting out for one night before use.
- Aquatic fauna: Betta fish (recommended, click here for more information), freshwater snails, crayfish, etc.: Pet stores, creeks, ponds
- Terrestrial fauna: snails, worms, pill bugs, small insects (fruit flies, earwigs, beetles), millipedes, etc.: The woods
The Exacto knife contains a sharp blade. Always remember to cut away from yourself. It may be easier to cut the bottles while holding them horizontally. To avoid injury use caution while using the Exacto knife. Keep Exacto knife away from small children.
Children should be supervised if using the hammer and nail in order to avoid injury. Be sure to work on a hard, flat surface when using these items to avoid injury and damage to work surface.
Step 2: Cutting the Bottles
Tip: Label the bottles: Bottle 1, Bottle 2, Bottle 3
1. Use the measuring tape to measure 1 inch higher than the label on Bottle 1
Tip: Use the rubber band and the Sharpie to draw lines where you want to cut (see above images)
2. Use the Exacto knife to cut Bottle 1 where you just measured
3. Use the Exacto knife to cut Bottle 2 at the bottom of the label
Tip: Keep the bottle cap for Bottle 2
4. Use the Exacto Knife to cut Bottle 3 at the bottom of the label
Tip: Keep the bottle cap and the cut off bottom of Bottle 3
5. Peel labels off of all bottles
Step 3: Cutting the Bottles- Part 2
6. Use the hammer and nail to poke 5-6 holes in the bottom piece of Bottle 3 (see above image)
7. Use the hammer and nail to poke 5-6 holes in the cap of Bottle 2
8. Use the hammer and nail to poke 5-6 holes in the cap of Bottle 3
9. Use the Exacto knife to cut a 1/2 inch by 1/2 inch flap 1 inch from the top of Bottle 1 (see above images). This flap is what will allow you to feed your aquatic organisms.
Step 4: Bottle 3- Terrestrial Layer
1. With the cap on, add about 1 cup of small rocks
2. Fill the bottle approximately halfway with moist soil. If the soil is very dry, mix with a little water before putting it in the bottle.
3. Distribute seeds atop soil
4. Cover the seeds with a thin layer of soil, about 1/4"
Step 5: Bottle 2- Decomposition Layer
1. With the cap on, add about 1 cup of small rocks
2. Place 2 handfuls of moist soil in bottle
3. Fill bottle halfway with organic matter
Optional: place pill bugs, worms, or other small arthropods in this layer.
Step 6: Test
1. Put Bottle 3 on top of Bottle 2
2. Pour water into Bottle 3
- If water comes out of Bottle cap 2 continue to next step
- If no water comes out of Bottle cap 2 refer back to steps 7-8 of Cutting the Bottles- Part 2
Step 7: Bottle 1- Aqua Layer
1. Add about 1 cup of small rocks
2. Place the aquatic plant into the aquatic chamber so that the roots are covered with rocks
3. Add water into the aquatic chamber (Be sure not to fill the chamber above the feeding hole made in Step 9 of Cutting the Bottles- Part 2)
Optional: Add the Beta fish and/or other aquatic fauna
Step 8: Finishing Up
1. Stack the bottles as follows:
- Bottle 1 on bottom, Bottle 2 on top on Bottle 1, Bottle 3 on top of Bottle 2, bottom piece of Bottle 3 on top of Bottle 3
Note: Don't be worried if your terrestrial chamber bottle sinks down into your decomposition chamber, this is normal and will not pose an issue.
2. Add water to the bottom piece of Bottle 3.
Note: If the cap of bottle 2 dips into the water in your aquatic chamber (like in the pictures above), remove water until there is about 1/2 inch or so between the cap and the water's surface. Failing to do say may prevent proper drainage.
For Classroom Instruction: You may want to complete “Cutting the Bottles” (steps 1-8) before class.
Caring for your Eco-coulmn: Add 1 cup of water to Eco-Column every 4 days.
Thanks so much for reading! We hope you enjoy your homemade eco-column! If you have any questions or suggestions feel free to leave us a comment!
Third Prize in the
Indoor Gardening Contest