Soak five dry Lima beans beans in a cup of water for several days or at least overnight. Remove the beans from the water and place on a paper towel. Fill five clear plastic cups with potting soil. Place one bean in each cup, two inches deep into the soil and near the side of the cup, not the center, so you can see it through the cup. Place planted beans on a window sill. Since watering is an activity that preschoolers can complete themselves with an easy-to-handle watering can or plastic cup, allow the children to take turns watering the plants daily.
Have students keep a growth journal. Picture journals are ideal for preschoolers who cannot write words. Have the children draw pictures of the bean plants at key steps, including the bean alone in the cup, the roots growing, the sprout growing, the sprout breaking through the soil, and the first leaf appearing. Keep the sprouted plants on the window sill and continue observing healthy growth as a class. Discuss what plants need to live: water, sunlight, and soil.
Take one sprouted plant and place a box over it to block sunlight; continue to water the plant daily. Lift the box in three days so the students can see and draw what happens when a plant doesn't have access to sunlight.
Take one sprouted plant and label it "No Water" or a picture of a drop of water in a circle with a line through it - the universal symbol for "no." Keep the plant on the window sill and stop watering that plant. Have students observe and draw what happens when a plant doesn't have water.
Take one sprouted plant out of the soil and place it on a paper towel. Continue watering the plant and keep it on the window sill. Have the students notice and draw what happens when a plant doesn't have soil.