Rain gardens do not cultivate rain. They are not ponds or wetlands. Most of the time, a rain garden isn’t wet at all. So…
What is a rain garden?
A rain garden is a sunken area designed to redirect rain water away from buildings, driveways, lawns, and other landscape features that may have drainage problems, and to hold onto that water long enough to filter sediment and pollutants. Rain gardens typically use native plants that do not require additional irrigation. These plants help hold, filter, and slow the release of rainwater, reducing runoff and pollution, while allowing more water to be absorbed. This usually occurs within 48 hours, preventing mosquito breeding. According to The Groundwater Foundation, “Rain gardens are effective in removing up to 90% of nutrients and chemicals and up to 80% of sediments from the rainwater runoff. Compared to a conventional lawn, rain gardens allow for 30% more water to soak into the ground.” Now, industrial and commercial properties have high tech rain gardens that incorporate sand and filtering systems and all that, but we, as homeowners, don’t need to go quite that far to get similar benefits.
Why have a rain garden?
If you live in California, you know that our occasional rains can be disruptive. The ground can be dry to the point of becoming hydrophobic, repelling water and causing flash floods. You may not have a flash flood in your yard, but the principles behind rain gardens can still help prevent the loss of topsoil and other problems associated with urban drool. Also, the majority of the water that comes off your roof and driveway contains a lot of pollutants that you probably don’t want in your edibles. Installing a rain garden also helps attract beneficial insects and other pollinators, increasing biodiversity. Rain gardens are very low maintenance once installed and they look nice!
How and where are rain gardens installed?
Since most of the water for your rain garden will probably come from rain gutter downspouts, you will need to select a location that allows for a path (read decorative trench) from those downspouts to a low area in your yard. Areas with full sun are preferred over shady areas. You will want to make sure that your rain garden site is at least 10 feet away from your home or other buildings and not over a septic field. Once you have a location, use these steps to create your rain garden:
This is a big project, but it is one that will improve soil and water quality in your area for a very long time. If you have the space, consider adding a rain garden to your landscape. (And be sure to share photos!)
You can grow a surprising amount of food in your own yard. Ask me how!