Background
Rain gardens are planned gardens that capture, and filter, rain water that would otherwise run off, or through, your property.
Runoff is a serious problem where increased development has replaced land with impervious surfaces roads, roofs, patios, etc. that preclude rainwater from soaking into the ground.
Problems Associated with Rainwater Runoff
- Pollution of streams and water supplies as rainwater picks up chemicals from roads, lawns, farms, and parking lots
- Erosion of surface soil and subsoil, sometimes resulting in sinkholes and structural damage
- Reduction of replenishment of groundwater supplies
Benefits of Rain Gardens
- Youll help the local environment and improve the beauty of your immediate surroundings. Once established, rain gardens are nearly maintenance-free and very attractive.
The Basics
1. Locate your rain gardens at least 10 feet from your house to prevent water accumulation around your foundation.
2. Dont put it immediately over a septic system.
3. Your rain garden should be 4 to 8 inches lower than the surrounding surface of the lawn, to trap rainwater for a short period of time, allowing it to seep into the soil
Plan Your Rain Garden
Select a location where water runs off or through your property.
Then, decide how big your rain garden should be.
For very sandy soil, plan on 20% of the total area of impervious surface.
For loamy soil, the area should be about 35%.
For heavy clay soil, your garden may need to be 50% of the impenetrable area.
Second, decide the shape. Shapes similar to squares and ovals work better; long, skinny gardens wont capture much runoff.
Third, decide what to plant. Experts recommend native plants, because they will thrive in your climate. For specific recommendations, you can Google Rain Garden Plants for [your state].
How to Build Your Rain Garden
First, remove the sod from the area, roots and all.
Second, add compost, which will significantly improve both the fertility and tilth of the soil. The Mantis tiller is especially good at mixing compost into the soil. For more on compost.
Third, plant native plants. You can include trees and shrubs, which will develop large root systems and absorb a lot of water.
Fourth, mulch the garden to help prevent weed growth. My first choice would be a thick layer of well pulverized brown leaves (not walnut leaves oak or maple are ideal).
Fifth, water the garden until it is well established. Youre your newly transplanted trees, shrubs, and flowers for a little while. Once established, the rain garden should be almost maintenance free.
Get Started!
Start with a plan, but get started. You might find that you want to change your plan later. If youve picked the right spot, that will be easy. Remember, any rain garden is better than no rain garden.
