Rain gardens are gaining in popularity fast, especially in areas with lots of rain fall. And it’s easy to see why: Rain gardens absorb and keep the water, helping with proper drainage AND look pretty!
A rain garden is basically a basin with plants and flowers where water can collect. The deep roots of the plants make the soil work like a sponge, keeping the water in the basin and the earth below.
If you have problems with lots of water collecting somewhere in your yard, this could be the answer to your problems!
Another good reason why you should try “rainscaping”: it can not only look quite pretty and unique, but it can be done over just one weekend!
If you want to build one, you should get a professional contractor to help you. They know best which plants to use. Ideal are native plants with deep roots, to make the soil a better water storage.
Also, you will still need to build a way for excess water to flow off, in case of heavy rain. This outflow should also have some kind of natural filter. Otherwise, a lot of other material may be carried away by the water.
How to build a Rain Garden
A rain garden should consist of three rings. The innermost ring is at the lowest point, the plants should be able to handle “wet feet” and ideally native. In the second ring, the plants should still be comfortable with standing water occasionally. In the outer ring, place plants that like drier climate.
There should be a bit of a slope downwards into the middle, so the water may collect in the center of your raingarden.
Where to build a Rain Garden
The lowest point in your garden may seem like the most logial place. But no.
Pick a place somewhere close to the lowest point, but not where the water already collects. The soil there will be too soggy already.
Also, keep some distance to your house, at least 10 feet.
Then, test the soil’s “percolation rate”, how fast it can absorb water:
Dig a two-feet hole, and fill it with 8-12 inch water. Then wait until it disappears. Then, calculate the water (eg, 8 inches) by the hours (eg, 11 hours).
If the percolation rate is above 0.5, this is a great spot. Your rain garden should be about 18 inches deep.
If the ratio is lower than 0.5, your rain garden should be about 30 inches deep.
If the result is lower than 0.1, this area is unsuitable for a rain garden.
Design the Rain Garden
In short, draw a sketch of your existing garden, and draw some ideas how the raingarden could look like. Make it an irregular, round shape for a natural appearance.
For the flowers and plants, refer to the design guidelines to help you with the choice.
Rainscaping – not always DIY
Especially if you need a bigger rain garden than just a few feet wide, you will need bigger machines to build it. For that, you will need a landscaping contractor, their knowledge and experience will be invaluable for a satisfying outcome. ThisOldHouse has a great article on the details of building rain gardens if you want to see how the process works.
Also, check here if you qualify for an incentive for building a rain garden!