There are plenty of smart gardening kits available on the market. The Grüt happens to be one for kids. It has sensors and an app to show your kids how to take care of their plants. It can detect temperature, light, and soil moisture. The companion app shows a virtual avatar of the plant and provides feedback to show your kids how to take care of their plant.
Grüt is easy to use and provides your child with an engaging experience. You can find out more about it on Kickstarter.