At Home for Earth Day: Plastic Bottle Terrarium
A terrarium is an enclosed environment created for plants, which needs very little outside intervention once it is set up. In celebration of Earth Day, let’s create a basic terrarium from an upcycled 2-liter plastic bottle. When it is complete, our plant will receive sunlight through the transparent walls of the bottle, and it will obtain water from its own water cycle!
Materials
Empty 2-liter plastic bottle (with cap)
Potting soil
Pebbles
Small plant(s) (choose species that like high moisture levels)
Spade (optional)
Coffee filter (optional)
Scissors
Procedure
Have an adult carefully cut off the bottom 6 inches of the bottle
Place a layer of pebbles in the bottom of the bottle
Optional: cut out a circle of coffee filter and place it on top of the pebbles to prevent soil from mixing in with drainage pebbles
Put about 4 inches of soil into the bottle, on top of the pebbles
Use your finger to make a small hole in the center of the soil
Nestle the roots of your plant into the hole, and pack additional potting soil around the roots and stem until your plant is firm
Add just enough water to moisten the soil, but not soak it
Put the top of the bottle (with cap on) back onto the bottom portion, and your terrarium is complete!
Place in a location where it can receive indirect sunlight. In direct sunlight, the inside of the terrarium will become too warm, and the sides will fog up.
In a few days, you may add a bit more water if needed, or leave the lid off to allow some excess water to evaporate. Once your terrarium achieves the appropriate moisture level, it should be self-sustaining.
How Does It Work?
Your terrarium basically acts like a greenhouse, with everything your plant needs right there in its environment.
Sunlight enters through the walls of the bottle and warms the air, soil, and plant the same way that sunlight coming through the atmosphere warms Earth’s surface. The bottle holds in some of the warmth, just as Earth’s atmosphere does.
Sunlight enters through the transparent walls reaches the plant’s leaves, allowing the plant to produce its own food through the process of photosynthesis.
The sealed container combined with the heat entering the terrarium allows for the creation of a small scale water cycle: moisture from both the soil and plant evaporates in the elevated temperatures inside the terrarium. The water vapor then condenses on the walls of the container, and eventually falls back to the plants and soil below.
