Planting bean seeds is a simple first gardening project. Soak lima beans or green bean seeds in water overnight and put them on wet paper towels. Put the paper towels and beans into clear sandwich bags, and hang them in a window until the seeds begin to sprout. This way the students can see what happens when seeds sprout. Once the seeds have sprouted, you can plant them in paper cups or small pots.
If you have a sunny window, plant flowers or herbs. If you don't have space for each student to have his own pot, you can use a larger rectangular planter and let each student put her own plant in the planter. The students can make plant markers by writing their names on craft sticks and decorating them. Try planting basil, mint, parsley and oregano for easy-to-grow herbs. Flowers that will sprout easily from seed are periwinkles, sunflowers and zinnias.
Cut the top third off of a sweet potato and place it in water to watch it sprout. In about a week roots will begin to grow from the bottom of the potato, and then leaves and a vine will sprout from the top. Cut the tops off of carrots or pineapples, place them in a pie pan filled with pebbles and water. Soon they will begin to sprout, too.
As part of your indoor gardening unit, you can also introduce your students to different types of soil.
Bring in samples of soil, sand and clay for your preschool students to observe. Let them use hand lenses to look at it closely. Encourage them to feel it and smell. Provide small cups and shovels so that they can pour it and move it from place to place. When everyone has had a chance to explore, let them share their observations.
Once your students have had the opportunity to work with the different soils, ask them which one they think will be best for growing plants. After discussing their predictions and why they chose them, you can plant the same type of seed in soil, clay and sand. Observe them over the next few weeks and talk about what happened in each soil type.