You can use rain water in your gardens thanks to this DIY rain barrel. Learn how to build a rain barrel to save water and to save money. Your plants will get the hydration they need, and your budget will be happy too.
Here is an idea for a vertical garden in a classroom (plus a fish tank). This could also work in other places -- homes, places of worship, community centres, etc. Maybe even outdoors? With a mesh covering over the fish tank, the cats couldn't get in.