In most suburban neighborhoods in developed countries, a common water pollution problem persists. The fresh rainwater from each storm runs from rain gutters, across lawns treated with pesticides, into dirty gutters, and finally down storm drains into rivers and lakes. Planting a rain garden offers an eco-friendly water solution and is a great compliment to beginner compost. Here’s everything you need to know about how to make a rain garden.
What is a rain garden?
A rain garden is a small, sunken garden located along rainwater’s inevitable path. By diverting gutter water into it, gardeners can help filter water into the surrounding soil in a natural and clean way. The water is redistributed evenly and naturally while the garden thrives. To the casual observer, a rain garden looks like any other attractive flower bed or border, when in fact it’s an ecological aide. There are so many benefits to having a rain garden too.
How to Make a Rain Garden
Before digging in (pun intended), follow these five steps for rain garden success.
1. Consider your climate.
Good news! Rain gardens will grow anywhere. The key is in planting your garden with native plants. A quick Google search will show beautiful images of rain gardens from Tucson to Albany, and in every climate in-between.
While rain gardens have become extremely popular in rainy climates such as Washington and Oregon, the rest of North America is not far behind. In fact, several cities, including many in the Midwestern US, now charge a storm drain water fee to suburban residents. If you’re a homeowner, you can avoid this by diverting your storm drain water.
2. Choose your rain garden’s location.
You’ll want to place your rain garden within the path of water run-off, or create such a path. For instance, plant a rain garden as a border along your storm drain spouts (at least 10 feet from the house). Another place that can be successful is adjacent to your garden shed. A garden shed can be a wonderful resource to store garden and other tools, a place for hobbies or even for a workshop. Another possible location is that it can be a central attraction of your yard in a natural depression in your lawn. If you want to place your garden outside the natural path of rain water, be prepared to dig a trench and lay down a drain pipe to direct your rainwater.
Your rain garden location also needs to absorb water at an ideal rate. Test potential sites by digging a hole two feet deep, filling it with water, and seeing how long it takes to drain. The ideal rate is above .5 inches per hour. Find this rate by dividing the number of inches by the number of hours it takes to drain.
3. Decide how big your rain garden will be.
The size of your rain garden will depend on the type of soil you’re working with in your region. Does it absorb moisture easily, like in the Cascades, or slowly, like in the high desert? Generally speaking, a rain garden 1/10th the size of your house roof should be able to handle 90 percent of your run off.
4. Learn which native plants will do best.
Of course, this depends on your area. Start by contacting your local garden store or the agriculture division of your local university or community college. Plants with deep roots do best, but don’t be afraid to add a variety of native plants to your rain garden.
Divide your garden into ringed zones: the inner zone at the center of your rain garden will be the plants that do best with the most water. Remember, your rain garden will include areas of high water content and areas that remain drier.
5. Determine whether you need a drainage system below your garden.
If your budget allows for it, you may want to instill an ‘under drain’ below your rain garden to carry cleaned water away. (This is important if the soil around your garden is unclean, thereby contaminating your clean water should it drain into it.) If you opt not to add this feature, your garden will be self-contained; make sure the plants selected can withstand excess water.
We saw an excellent display about how to make a rain garden and about rain harvesting at the Discovery Center in Milwaukee if you are ever in the area. We also took our kids to Hastings Museum in Nebraska which had a great nature area.
After following the steps above, you’re ready to get started with your rain garden. This step-by-step rain garden tutorial is a great place to start! Plan for a full weekend of work ahead of you, with rewards that will last the whole year!