You can make a terrarium from a plastic pretzel jar. This is a fun and interesting way to watch plants grow your house. It is also a great vocabulary builder, as kids learn the names of plants, scientific terms (condensation, humidity, tropical, etc.) and planting ingredients. Invite your school-age kids to help with the process. Younger kids can help with some of the preliminary activities getting the jar ready.
Safe Plants at: momtomadre.org/2013/03/03/safe-flowers-flores-inocuas/
Toxic Plants at: momtomadre.org/2013/03/03/toxic-flowers-flores-venenosas/