Monday, December 21, 2009

Getting Your Rain Garden Started

The information below was compiled by the Clemson University Extension Service to help you plan your own rain garden.

So, what’s a rain garden?

• Appealing landscape ideas for homeowners and Property Owners Associations.
• Allows collection of stormwater and infiltration.
• Plants and microbes do the work of pollutant removal.
• Can be attractor for wildlife such as birds and butterflies.
• A natural way to irrigate.

Where do we put the rain garden?

• Between rainfall runoff “source” and “destination”.
• We want to intercept the water before it reaches surface waters or low spots!
• Gutters and downspouts help direct rooftop runoff flow.
• Driveway and sidewalk edges can also make good locations.
• It’s important to watch how water flows during a storm event!!!
• Install your rain garden more than 10 ft. from building foundation, and more than 25 ft. from a septic system drainfield.
• Avoid shallow water tables (less than 18 in. deep).
• Away from utility lines.
• Ensure no buried cables or pipes in the excavation area.
• In full to partial sun, if possible.

What size should the rain garden be?

• Determine the area of impervious runoff source (rooftops + sidewalks + driveway areas).
• Rule of thumb: estimate the size of your rain garden based on soil types:
Sandy soil (well-drained) = 20% of impervious area.
Loamy soil (poorly-drained) = 20-60% of impervious area.
• May be limited by the space you have, but smaller is easier!!
• The excavated area should be 6-8” deep.
• The area should be typically 8-10 ft. wide in the direction of runoff flow.
• Try using a kidney bean or half moon-shaped layout with the inner curve of the area facing the runoff source!!

How do I know if it’s in a good spot?

The ability of rain water to drain is important for your rain garden location:
• A simple “perk” (percolation) test can help you to decide:
1. Dig a hole about 6 inches deep and wide
2. Fill the hole to the top with water
3. Check the hole 24 hours later – if the water is gone, you have an ideal rain garden location, otherwise, consider a backyard wetland!!

What kinds of plants should I use?

• Hearty species with a range of drought and wet condition tolerance.
• Options include small trees, shrubs, perennials, and grasses.
• Please use native species!!
• Plants that attract butterflies and hummingbirds.
• A plant list is available – contact the Beaufort County Clemson Extension office.

How much will my rain garden cost?

• For an 8 x 20 ft. garden:
• Plants = $200 (retail; cheaper if you use wholesale or transplanted).
• Soil mix and mulch = $200 (retail; cheaper if you use bulk or fill).
• Labor = free (don’t forget to use your friends).
• Total = $400 (~ $2.50 per sq. ft.)
• Protecting water quality = PRICELESS!!

Please visit the websites below for a wealth of information on smart Lowcountry landscaping and to learn the things all property owners can do to protect water quality and our delicate Lowcountry environment: Clemson’s Carolina Yards and Neighborhoods program has practical and comprehensive information on how to irrigate and landscape responsibly. Clemson’s Home and Garden Information Center is the resource for all of your horticulture and landscaping questions. This website is the home base for Clemson’s statewide Extension Service system. Beaufort County’s Clemson Extension Service office can be found at this website. Or contact their office at (843) 470-3655.

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