This is a good article about the benefits of gardening with kids..
These are fun to do with kids to, we made bug rocks with my boys and we are always looking for good shaped rocks that we can paint.
This a good way to reuse your old boots we made a pair and lasted for 2 years ,would have lasted longer if the dog didn't destroy them.. They looked great outside our front door.
You just need to put small stones at the bottom first for drainage and them some good soil
These are fun to with the kids, we did these little fellows with lentils and beans..
This is a good link with some stuff to do for the garden.
This is a good way reusing your bottles ..and easy for kids to water the plants.they can personalize there watering jugs by painting on them and sticking stuff on them.
Look at this lovely magical photo ,want lovely lay out and love the lights hanging on the tree.
This is one project that I've been meaning to do with the boys, a good way to personalize your garden with stepping stones made by you and the kids. Something that you would look at after many years and remember ..http://m.wikihow.com/Make-a-Seed-Bomb
Another good activity to do with the kids.. To save seeds for next season or to give as party favors.