the best time I had planting with kids was when my neice and nephew were small. they wanted to plant
. so they planted the radishes, green onions, leaf lettuce, they wanted corn, knowing they didn't like it, I got some popcorn and they thought that was great.
I also constructed a tee-pee out of really long dowel rods, thick ones, then we planted pole beans on them, the kids would get in the middle of it and pick the beans. Worked out great, they had a little hiding place and they had a great time picking the beans. It is easy, just get the dowel rods, form them like a tee-pee tie off the top really well and don't forget to leave an opening so they can get in and out.
I still giggle when I think of that one,lol.