Determining the size of your Rain Garden is easy, as long as you know what to look for. To determine where you should place your garden, ask the following questions:
Where should I place my rain garden?
Look at your property during and after a good rain to see which way water runs and where it accumulates. Rain gardens should be established in areas where water collects in a depressed area of your yard. It does not benefit you to place your rain garden on one side of your yard if all your stormwater runoff is located on the other end of your yard.
How big should my rain garden be?
Determining the size of your rain garden starts with determining the size of the area from which water is flowing. For example, if you are planning to build a rain garden in order to deal with runoff from your roof, you must first know the size of that portion of your roof. Your rain garden should be about 20-30% of the area from which the water is flowing.
How do I know my soil will work for a rain garden?
To determine if your soil is the correct mixture, conduct a perk test. Dig a hole the size of a coffee can in the area where you want to place your rain garden. Fill the hole with water, and check to see if it drops 1 to 6 inches in an hour. If it does, your soil is good for a rain garden. If not, contact your local nursery or a Clemson Extension office to find out how to amend your soil so you can use it for your rain garden.
Clemson Extension Phone: 1-888-656-9988
Clemson Home & Garden Information Center Guide
Choosing Your Plants:
Native vegetation is perfect for rain gardens as it is accustomed to the local climate! This means it is better equipped to deal with natural rain fall, droughts, and temperature changes.
Arranging Your Garden:
It is important to remember that the water spreads as it moves through your garden. Thus, it is necessary to place plants which can handle more water closer to the source, and plants which can handle less near the edges. Check with your local nursery to determine how much water a plant can handle, and then determine whether it should be placed near the edge of your garden, or close to your source.
Add a Rain Barrel to Your Project:
To further reduce runoff form your roof, you can connect a rain barrel to your downspout and direct the collected water through a hose to a desired area. This lowers the percentage of roof runoff needed to be managed while providing a naturally softened, chlorine-free source of water for houseplants, shrubbery beds and window washing.