Kitchen scraps make fantastic compost… which makes fantastic veggies. We started with a big compost pile… just walk out and throw the kitchen scraps on, mix it up once in a while, throw in some grass clippings, sticks, twigs, hay if you have it. A good mix of green and brown stuff… and then eventually you get black gold… the stuff gorgeous vegetables are made of. 
Putting kitchen scraps in a bucket and taking them out to the compost pile, or compost tumbler is something even the smallest children can wrap their minds around and enjoy. We got Hanna involved in composting really early on. She loved the idea that our “wasted food” was going to help the veggies grow.
We aren’t the most organized around our composting… we have a big bowl on the counter. I’d love to have a real composting type bucket… and maybe I’ll get one this year. We also have a little fruit fly trap… or my husband probably would refuse to let me compost lol.
Hanna has always looked forward to taking the bucket outside, and throwing it on the pile, or dumping it in the tumbler. She also really enjoys spinning the tumbler.
What I’ve found is at a very basic level, if we can manage to make it fun and easy for kids to learn… they will. They will not only learn, but they will love it, and they will share what they’ve learned with just about anyone who will listen.
I’m thinking about doing some vermiculture this year as well… I think Hanna would LOVE watching the worms do the composting for us! Here’s more information if you’re interested in composting with worms.
