Click here for a PDF of Rain Garden Basics.

• Before you dig the garden call the power company! In Wisconsin, call Digger’s Hotline: 800-242-8511. They’ll come to your house for free and locate your underground utilities.

• Put the garden at least 10’ from the house to keep your foundation dry.
- A low area can work. Native plants will break up the soil and allow infiltration.
- Border gardens are usually more attractive than circular gardens in the middle of the yard.

• Make the garden 150-300 sq ft.
- Aesthetics and maintenance should determine the size of a home garden. Even an undersized garden will do a lot of work to infiltrate water.
- If the soil is clay, the garden should be large and shallow; If the soil is sandy, any size or depth is okay.
- Rule of thumb for sizing a rain garden: Make the garden 30% of the roof area if the soil is clay, 20% if sand.

• Make the bottom of the garden flat.
- It should look like a saucer, not like a bowl. This allows infiltration everywhere and reduces the likelihood of standing water.
- If you know someone with a surveyor’s level, that’ll make the job much easier.

• Make a low berm around the garden to hold water.
- The garden only needs to be about 3” deep.
- Think about where the garden will overflow during the heaviest rainfall. It should empty away from the house, not toward it.

• On slopes you may need a small terrace wall.
- The downslope wall shouldd be half as high as the rise to the top of the slope.
- On steep slopes, plant natives directly on the hill without digging a depression. The plants will infiltrate runoff. A tall retaining wall can fail catastrophically if it gets too wet.

• Water transport.
- If your garden is in a natural low area, just direct your downspouts toward the garden.
- You can dig small swales that lead from the downspout to the garden. Plant the swales with grass or line with rocks.
- Buried pipe from the downspout to the garden is another option.

• Digging the garden.
- It’s usually not too expensive to hire someone to prepare the site.
- If you dig by hand, take your time and enjoy the work.
- Mix in compost if you feel like it. Compost absorbs water, but it can encourage too-tall plants. Get free compost from Dane County. www.co.dane.wi.us/pubworks/recyc/compost.htm

• Use native plants. The long roots infiltrate water.
- 1 plant per square foot.
- 15 different species, or more. Avoid cultivars (i.e., named varieties).
- 30-50% sedge (some grasses work, too). They help the plants stand up.
- Choose plants mostly based on their height and on their light requirements.
- Here is a list of recommended plants.

• Maintenance.
- Cover with wood chip mulch the first year. In Madison, WI, get free wood chips at Warner, Sycamore, Elver, and Garner Parks.
- Water the first year.
- Weed the first 2-3 years. Minor weeding thereafter.
- In winter, leave the dry stems for habitat and seeds. Cut them down in April and compost them.

• Enjoy!
- Your garden will not only infiltrate and clean stormwater, but provide wildlife habitat, too.

Sources of plants:
www.prairienursery.com
www.agrecol.com
www.appliedeco.com/tcrn
www.prairiemoon.com
www.prairieridgenursery.com