In spite of great strides in cleaning up our waters, stormwater runoff still washes chemicals, oil and litter from streets, roofs and lawns into streams, rivers, bays and oceans.  This runoff is called “nonpoint source pollution,” a technical way of saying it doesn’t come from any single source. 
Although preventing this type of pollution is difficult, there is something we all can do to help! Rain gardens are a terrific way to work with nature to slow down stormwater pollution while creating beauty. Rain gardens are specially designed to capture runoff water so it can to be filtered naturally as it slowly seeps into the ground. Homeowners and businesses can reduce runoff from their properties by building rain gardens.
Creating a rain garden is easy. First, find the area(s) of your property where water pools or flows during a rainstorm.  Make sure it’s 10 feet or more from your foundation and not right on top of your septic system or utility line.  Avoid areas that get a lot of foot traffic, and those next to large trees. To make sure the drainage is good, dig a 6- to 8-inch test hole and fill it with water; it should drain out completely in 12 hours.
Once you have found the location, plan the garden.  There’s no such thing as a rain garden that’s too big, but for sandy soils, 10-20 percent of the size of the total drainage area is best. Larger gardens are good for loamy and clay-like soils, but depth is also important.  The ideal depth of a level rain garden is 3-5 inches, but you can make it deeper and shrink the surface area a bit if needed.  The bottom line:  a rain garden needs to be slightly below grade, and any size helps!
When digging out the garden bed, make it as level as possible so it will hold water.  An irregular shape and curved edges also help.  If the garden is on a slope, dig the uphill side deeper to make the bed as level as possible.  Avoid compacting the soil in the bottom of the garden bed.  On the downhill (or “downstream”) side of the garden, use soil to build a berm a few inches high to help retain water in the garden.
Now you’re ready to plant!  Use a variety of native perennials that grow well in moist soil.  If your garden is large enough, consider water-loving shrubs and trees.  A few questions at your local nursery will yield an array of colorful choices for any size garden.  You can also reinforce the berm of your rain garden with grass or groundcover plants; this regulates the flow of water into the garden on one end, and holds it in on the other.  Finish with a 2-inch layer of mulch.  Maintenance is the same as for any other garden - water and weed when needed.
It’s great to know that you can create beauty and help protect water quality right in your own backyard! A bonus is all the birds and butterflies your new rain garden will attract.
The New Jersey Native Plant Society has step-by-step instructions and advice on which native plant species to use in various soil and light conditions. Go to to download their Rain Garden Manual.
And if you’d like more information about conserving New Jersey’s precious land and natural resources, please visit the New Jersey Conservation Foundation’s website at  or contact me at .