Grand kids in the garden

How do you motivate grandkids in the garden and keep them outside instead of in all the time.

 

What I did with my son's is I had them have competitions, the first year I told them we needed to see who could crow the biggest sunflower, the second, pumpkin and the third we watched to see which of the two boys could grow the best bean pole tee pee. It really got them interested in gardening