Last year, when DD was 2, we put 2 parsley caterpillars in a container (I used the plastic containers which held 4 lbs of cherries from Costco) with parsley. I read about their habits, and figured out when the crysalis was coming and put them in another simlar container with sticks. We watched them the whole time and then when they became butterflies, we set them free.

I also soak seeds (for small fingers, sunflowers are best) and then we can plant after they root. Also, they see the sprout before planting.

I also got a tomato plant and we took care of it and she picked the tomatoes. And herbs and we named them, smelled them. She wouldn't taste.

Have fun.

Ren