"I Will Plant a Tree" T-Shirt

Your grandchildren may already have their minds set on being firefighters or astronauts, but there are, of course, smaller things they can do to improve the world around then (once they're old enough). The "I Will Plant a Tree" T-shirt, made of organic cotton and nontoxic water-based inks, announces the kids' good, green intentions for the future.

Age: 2+
Retail Price: $18
Available at: whenigrowupiwill.com

Idbids

These soft plush toys, modeled after a cloud, a drop of water, and a flower, are each packed with their own story and a "field guide" that teaches young grandchildren "iddy biddy steps" to energy conservation. With an Idbids starter kit, grandchildren check off little tasks like turning off the water when they brush their teeth and turning off the light when they leave a room, and make a new snuggle-friend in the process.

Age: 3+
Retail Price: $25
Available at: multiple sellers

PlanCity Eco Town

This utopian little play set features a model "battery-charging" station for its tiny electric cars, an eco-train station, and a small, solar-powered home. Grandchildren can play civil engineer as they arrange each part of this Eco Town, (the wooden set requires no batteries or electricity) and pretend they're responsible residents while they scoot around town.

Age: 3+
Retail Price: $150
Available at: polkadots.com

Recycle Truck

A green addition to your grandchildren's toy-truck collection, the Recycle Truck is a bit different from your average dump truck on its way to a landfill. The monster vehicle teaches grandchildren the concept of reuse and renewal, and it's made with recycled material itself. Watch a video demonstration of the truck from this year's Toy Fair here.

Age: 3+
Retail Price: $25
Available at: amazon.com