How to make a rain garden

“1. Dig a coffee can-size hole where the deepest part of the rain garden will be. Fill the hole with water. Mark the water level with a Popsicle stick.

After four hours, measure between the stick and the new water line. If the water fell one inch, the soil will percolate 6 inches in 24 hours. Your rain garden should be a maximum of 6 inches deep.

“2. Use stakes and string, or a hose to outline the shape of the bed. Think about where rain goes in and overflows out.

If possible, direct your downspout into the rain garden. Use “splash rocks” to disperse rain and keep soil from washing away near the downspout. Plan where rain will overflow during storms with very heavy rainfall.

“3. Dig a flat depression 4 to 8 inches deep, at least 10 feet from buildings with foundations and away from septic systems and utility lines. Fill the bed with water to double-check drainage before planting.

If the bed does not drain, remove 3 to 4 inches of soil. Add peat moss or compost. Till deeply, about a foot, to loosen compacted soil. In the first year, you also can cut a notch at the top garden to let rain flow out; the bed will not fill to the top, allowing plants to establish root systems for infiltration.

“4. Place plants in pots on the bed, according to your design. Gently remove them, break up the roots, and plant.

Use shredded hardwood mulch to prevent weeds and to add nutrients.

Irrigate the bed once a week with one inch of water, until plants are established. Pull weeds as needed. Each spring, prune dead vegetation, prune plants that are too big, and add more mulch.

Before you dig: If you suspect that utility lines might be buried in the area where you will dig, or if you are putting the rain garden in a utility right-of-way, call your local utility-finder.

Source: 10,000 Rain Gardens.