Nice idea of putting up a garden for your kids! I believe you're planning to put up a soil based garden for them and that's quite good, but have you also considered going hydroponic? Just a thought :) Good luck on your endeavor ;)

My 6 yr old is growing sunflowers and tomatoes....my 10 year old is growing tomatoes and onions.

They help me water..and I'm teaching them how to identify weeds to pull out..and just generally about bees and butterflies..even the bad bugs.
They have learned how carpenter bees live....what carpenter ant do, and why we want to try and keep them safe so the fireants won't take over.

They love to harvest the peas..and have learned that it's kinda cool to eat right there in our garden.

The more the season goes along..the more questions they ask..and the more research I have to do....but, hopefully they are learning that being as self sufficient as possible is the way to go..and that wildlife is something to appreciate..not kill.

My 6 year old helped me plan a good deal of my flower bed this year too......now she actually takes care of things rather than not caring about them at all.

I'd say start with something really cool like carrots and greenbeans or tomatoes....things they can pick and eat( if you are not using chemicals) my daughter gets a kick out of carrots. my son thought beets were cool til he tasted one...now, not so much. lol
He's growing corn now.

You might want to add some flowers in your son's garden. My nephew loves melons, so I told him that radishes around the melons (and pumpkins) will help keep bugs away and nasturtiums are good, too. Catmint is also a good companion plant. My nephew takes his watermelon, radish and nasturtium seeds with him everywhere when he "helps" in the garden, as it's too cold to plant here for another week or two :)

I was also going to suggest radishes. They demonstrate in a very obvious way the importance of thinning seedlings. Plus the quick maturity rate lets the kids get some "instant" gratification to tide them over. And of course the other points about how they distract bugs away from preferred plants, etc.

I like the nasturtium idea as well. I was teaching inner city kids how to start seeds in plastic containers. I had a big selection of seeds to choose from but they all gravitated to the nasturtiums. Probably because of the edible flowers.

Thanks for all the great ideas. Right now, I'm debated doing one big garden for the both of them or doing two small ones. I have already started a bunch of seeds in the garage with both of them and we'll be transplanting outside soon. Right now, looking at green beans, sugar snap peas, carrots, tomatoes, sunflowers, marigolds, zinnias, and prob some pumpkins if I can fit them in somewhere. I'm glad I started all the seeds indoors and can now move to moving them outside, I just hope it's not too late for some of them. If it is, we'll just have a late crop of veggies. Thanks all for your input. I have written all these great ideas down and will implement some if not all as we go along. Thanks so much again.

I am also planning for the same but my baby is of only 1 yr.I will implement it in next year.