Garden Designs

It's easy to add a rain garden to your landscape! Just decide where it will work best to collect and process rainwater.

To establish the size of your rain garden, calculate the square footage of the area where rain will runoff and divide by three. This will give you a rain garden that captures roughly 30% of the stormwater it receives.

For rain gardens attached to downspouts, there are two additional steps.

For example, take a 1,000 square-foot roof panel with two downspouts, one of which is connected to your rain garden. Divide 1,000 square feet (the square footage) by two (the number of downspouts). Multiply by one (the number of downspouts connected to your rain garden) and then divide by three to discover you should have a 167 square foot rain garden to treat the stormwater from one of the two downspouts channeled to your rain garden.

To calculate the number of plants planted on 18" centers, divide 167 (the square footage of this area) by 2.25 to find 74 plants. If your soil is extremely compacted or clayey, double your square footage figure and increase the size of your rain garden, OR amend your rain garden's soil (50-60% sand, 20-30% topsoil, 20-30% compost). If your area is very large, or you are revising an existing swale to make a bioswale, replace some or all plants with shrubs and trees that tolerate occasionally wet soil.

Most important, disconnect your downspouts from our sewer system and channel stormwater to rain gardens and rain barrels. Even if your space is limited, you can benefit from a rain garden and help improve our area's management of stormwater. The smallest measures add up and help improve our area's management of stormwater. Remember, every drop matters, every drop counts!

Once the size is determined, site your garden at least 10 feet away from its foundation. Use a rope or garden hose to test different shapes for your garden's footprint. Within the footprint of the rain garden, create a slight depression by excavating six to 12 inches of soil. This also helps by removing existing vegetation. Mound this soil in a shallow berm on the down side of the garden.

To give you some inspiration, check out our garden designs.