To sign ground, take both hands and form modified letter O signs with all fingertips facing up. Rub all fingers on each separate 'O' hand together, as if you are feeling some dirt between your fingertips. Then simultaneously turn your modified 'O' hands into flat, open number 5 hands, with your palms facing down. Both flat hands will then create circular motions mirroring each other in front of your body, as if to signify the ground area where the 'dirt' is found.
Teach your toddler the ground sign when you are looking at some ground, like a plot of earth in your yard or garden that you are about to set some grass to, or when you are looking at land from a little higher vantage point or an aerial perspective, like from the window seat of a car, train, bus, or an airplane.
Teach your toddler this sign in conjunction with other Earth- or nature-related flash cards.