What’s a rain garden? It’s a lowered garden bed planted with deep-rooted plants which will enjoy being watered by the standing water that pools when it rains hard. They can be planted in areas that already form puddles, or rain that collects on a roof or a paved area can be directed toward an area where a new lowered bed will be dug. Rain gardens help with storm water runoff and erosion, while adding to the beauty of a landscape.
Plan one for your school to get a lesson that combines math, art, ecology, and general earth science to create a terrific learning experience. Take it a step further and plant the garden you plan for a fine service learning project!
Creating a rain garden isn’t much more difficult than making a traditional garden.
- Observe During the next rainstorm, have the class watch through a window or step into a sheltered area and see where rainwater pools. Use class cameras to capture the location, or use stakes to mark the locations physically. Be sure to locate your rain garden at least 10 feet away from the building so you don’t get a water-logged building.
- Have students draw maps or use Google Earth to create a map of the school. Mark the locations of potential rain gardens.
- Decide which location will make the best rain garden. If you intend to follow up by planting the garden, invite school officials to join this discussion so you can get permission.
- Is there a depression in the ground already? If not, do the math and determine how large a space to dig. As a rule, your rain garden should be at least 20% as big as the area you hope to drain. So, if rain running off the roof is to be the source of the water for the garden, you’ll need a garden 20% as big as your roof. In fact, a smaller rain garden can help and there’s no such thing as too big a garden, but this step is good real-life math practice.
- Decide which plants to use. Rain gardens usually use native plants. Our local water district provides a PDF guide to native plants appropriate for our region; your local experts can help you identify good choices. You certainly need plants that don’t mind getting their feet wet, and deep roots are best.
- Measure the space. Learn how big the plants you’ve chosen will be, and plot the place and number of plants you’ll need. Draw plants into your garden maps with circles showing the mature size of the plants. More great math opportunities here!
- Contact a local nursery to determine the price of the plants and calculate a budget for your garden.
Actually planting the garden is a wonderful way to follow up.