Zach (my almost-four-year-old) knows what compost is, and he knows what goes in it and what doesn't. Nothing is cuter than him finishing his banana and asking "Mommy, can you put this in the com-post for me?". Makes me so proud he knows what that is, I had no clue until I was like 25.
He also knows about recycling and what goes in the bin and what doesn't. It's one of his little chores to gather recycling stuff and take it to our inside bin for me. He has chastised ME on more than one occasion "that goes in da cycling MOMMY!". And I thank him for it. He's my little reminder that everything I do matters.
He also is a fantastic eater, he knows that some foods "taste good, but aren't good for you" so you eat those only sometimes. And that "fruits and veggies make you big and STRONG!". He LOVES going to the "market", aka the farmer's market and helping pick out produce. He knows that his food comes from farms and grows in the ground, it doesn't magically appear in the store. He'll try anything to see if he likes it. He usually does it himself, but if not, we do insist "you have to try it to see if you like it and if you don't like it, you don't have to eat it".
I'm not saying all this to brag, although I AM so very proud of him for knowing all this. I'm just saying, teach your kids and start young. Include them in what you're doing, let them see it as normal behavior and they will grow up knowing no different and carrying on with the healthy green lifestyle.
What are some things that you do with your kids to help them learn about living green?