Here's an easy terrarium idea that doesn't require dirt (therefore it's a little less messy that planting a garden!) It's a fun way for young children to be able to observe how plants grow.
Here's what you'll need:
-a few dried beans (or other seeds if you'd like)
1. First fold the paper towel so it will fit into the Ziploc bag:
2. Get the folded paper towel damp. You can do this with a spray bottle, or in the sink. I got my hands wet and patted them onto the towel until there were no dry spots left. Put the wet paper towel into the Ziploc bag.
3. Skater a few dried beans (or other seeds) on the paper towel. The moisture will somewhat hold them in place. Seal the Ziploc bag.
4. Tape your bag planter/terrarium to the window. The warmth from the sun will case the water to condense on the inside of the bag and will create a cozy environment for your seed to sprout. Check back regularly to see how the seeds are doing. Within a week you're seeds will begin to sprout!