To ensure your cut is straight, you can put a piece of masking tape around the bottle and then cut along the edge of the tape. Ask an adult to help you cut the bottle. Use a pair of scissors or a utility knife to cut all the way around the top of the bottle. Set aside the neck of the bottle with the cap for later use.
If desired, you can add ½ an inch of pebbles to the bottom of the bottle for drainage. This should be done before adding the soil, but is optional.
If you are planting beans, the holes should be 1 inch (2. 5 cm) deep. Make the holes near the edge of the bottle. This way you will be able to easily see the roots growing.
Aside from beans, you could also try planting a variety of herbs, such as mint, basil, and oregano. [3] X Research source You could even grow root vegetables, such as carrots or potatoes. Just make sure you provide enough soil for these plants to take root.
If you tilt the bottle and water runs up the side, you have too much water.
You will no longer need to add water to your bottle ecosystem.
You can also add a label to the base of the ecosystem with the date and identifying number. This way you can record notes and compare it with other bottle ecosystems that you make.
You can discard the small base of the bottle because it will not be needed. Place the top of the bottle with the cap to the side, for later use.
Keep both pieces from this bottle. The base of this bottle will form the base of your ecosystem and the top will be used to as a cap to seal the ecosystem shut.
You should ask an adult to help with drilling the hole into the cap. Make sure to wear safety glasses when using the drill.
Screw the lid back onto the bottle. Set this piece aside for later use.
If you have to use tap water, make sure that you let it sit in an open container for at least 24 hours before using in your ecosystem. The chlorine present in tap water may kill any animal or plant species that you add to your ecosystem. Letting the water sit for 24 hours gives the chlorine time to dissipate from the water.
At this stage you could also add one dead leaf. This will provide a food source for any microorganisms in the water.
Alternatively, you could pick water plants from a local pond.
