Christina Caldwell does an excellent job showing multiple ways to upcycle plastic bottles for your garden.
Here are my favorites:
This bird feeder is easy to make and being made from a plastic liter bottle, it will hold lots of feed to last a while! Holes are cut near the bottom to place wooden spoons through so birds have a nice place to perch and eat the seeds. Once your done with that, place a rounded screw in the top of the lid so you can hang your bird feeder and you’ll soon see some very happy birds.
Cutting the bottom off a plastic lid and making a personalized green house for your seedlings is a great way to start them off. Plants such as bell peppers or tomatoes will thrive with this ‘greenhouse’ top while they’re young due to their love for heat. The lid will act as a sweater, keeping them warmer and more hydrated = happy plants. Just be sure to keep the lid off. Once your plants grow too large for the cover, simply remove the lid and save for later use.
Use as a Planter:
Don’t want to spend the money on planters? Use a plastic bottle to grow herbs or plants like carrots. Simply cut the top off, place soil and plant. Don’t forget to cut small holes in the bottom of the bottle as well so your plant can drain water if need be!
To see other DIY ways to upcycle plastic bottles, go to http://www.faithtap.com/6315/how-to-upcycle-2-liter-bottles-in-the-garden/.