What is a rain garden you may ask?
So the first thing to discuss is what is a rain garden exactly. Rain gardens aren’t anything new in the gardening world but their popularity and implementation are sky rocketing as home owners and gardeners alike become more conscious about their impact on the environment A rain garden is a garden within a depression filled with plants that can survive excessive water in their environment. The rain garden is a place to store storm water runoff on a property that may come from down spouts, driveways, or the yard. After the water is collected within the garden it infiltrates into the ground and back into the communities water supply.
Why Should I install A Rain Garden?
When rain water or snow melt moves through your property it will travel over your roof, driveway, or lawn and picks up all the pathogens, toxins, sediment, and contaminants before it enters back into back in to the community drainage system. These waffle drains that the water flows into connect directly to waterways that feed into large water management systems. After entering these systems the water drains into natural waterways like rivers, lakes and oceans. The levels of the pollution picked up from people’s yards become concentrated as they are collected and deposited and eventually become extremely harmful to aquatic life as well as humans.
With global climate change on the uptick it is believed that precipitation levels will continue to increase in the United Sates, which will increase the amount of storm water runoff we see. The challenge ahead with an increased amount of storm water runoff is the levels off pollution will follow this upward trend. With an increasing use of rain garden homeowners have the power to curb this trend and protect their communities.
Where To Build A Rain Garden
Just like any project planning is the crucial first step and should be taken lightly, take as much time as you need to plan this out and then add some more time. Unless your home is the at a low point in the neighborhood most of the water that comes across your property will come off your roof and down your drain spouts. If a side of your home that has more rain spouts then another then you may want to consider placing the rain garden on that side of your home. By simply connecting your downspout to a corrugated drainage pipe available at any home improvement store you can feed that water from the downspout directly into your rain garden. If you want to allow the runoff water from you downspout to travel over the grass and into the rain garden take a hose and let the running water flow from were your downspout meets the round, then watch the water move through the yard if it flows away from the house you can place it anywhere along the waters path. You can find a list of other factors that you should consider before placing your rain garden:
- Don’t place the rain garden in the low spot of your property, especially if it is always wet. This is rain garden and not a water garden, we want this garden to drain not stay wet all the time.
- Check they type of soil you have. If you place the garden in a heavy clay then it will take longer to dry than sandy or a loam soil would.
- A rain garden should never be located closer than ten feet to your house. The goal of these gardens is to have the runoff water leach into the ground, but we don’t want that water to move against your foundation and start to compromise the integrity.
- If you have a septic system or you are close to a water well stay away. These water systems should never co-mingle
- Try to avoid installing the rain garden on steep slopes. A moderate grade can be overcome with a retaining wall but then your project will become much more complicated. If you can stick to level areas or barely sloped you will be better off.
- Think about an overflow of water from you garden. If a tropical storm were to come through and drop ten inches of water on to your property where would the excess water flow after your rain garden was at capacity? Overflow is to be expected, it’s not a bad thing but you need to plan and make sure the overflow moves towards your house.
Rain Garden Placement Tips From University Of Connecticut Cooperative Extension
In order to decide if your soil is suitable to have a rain garden you should check the soils with the US Soil Survey Map.
If that map is to confusing or doesn’t seem to work for you there is another option. Conducting your of infiltration test. A quick infiltration test can be done in a simple three steps:
- In the area you are considering placing your rain garden dig a hole six to eight inches deep and fill the hole with water.
- Comeback to the hole six hours later and check to see if the water is gone. If the water has infiltrated the ground your soil is conducive to a rain garden. If however the water is still in the hole and takes six to twenty-four hours the site is not going to work for the garden. The site isn’t totally unusable but it would take amending the soil which can be a large project depending on the gardens size.
If your home is new construction you will want to take note of your soil. Home builder tend to remove the topsoil during construction and bring back two to three inches when the home is completed. These homeowners are now left with compacted subsoil beneath the thin layer of topsoil. Compacted subsoil will need to be broken up before a rain garden is installed because water will not drain and plant roots will not be able to penetrate.
Calculating The Size Of Your Rain Garden
In some parts of the country homeowners can build a rain garden that is needs to accommodate one inch of water as ninety percent of their storms will drop less than one inch of water. As a rule of thumb when reaching a large audience it’s suggested to use make the depth four to six inches, but you’re more than welcome to look into what your average precipitation is per storm. If you’ve placed your garden correctly then even if you do experience a storm that tops your garden the overflow should be of no worry to you. In order to measure the area of the garden you will need to follow the simple steps below:
- Take a measurement of the footprint of your home and calculate the square footage.
- Try and figure out how many of those square feet will be draining into the downspout that will feed into your rain garden.
- If you will be feeding water into this system from your driveway add the square footage of the driveway into your total so far. Take your total square feet and divide it by six. By dividing your square footage by six you’ve calculated how much garden space you will need to hole one inch of rain water into a six-inch deep rain garden. You can adjust your divider according to the depth you plan to make your garden.
- Now you can begin to design the shape of your garden, just remember to make it roughly as large as the square footage you calculated. Taking a garden hose and laying it on the ground along where you want your garden borders can help you visualize the shape. Ovals and kidneys are popular shapes for the garden but make sure to try to fit it into the theme of your landscape (if there is one).
How To Design A Rain Garden
Here are some broad ideas about how to design a rain garden. In order to get a more specific plant list for your location send your email address and we will send it right out to you.[Form id="4"]
- Pick the right plants for your area. Consulting the USDA Hardiness Zone Map on our site will help you find your climate zone. Using native species for your geographic location will help make sure of survival.
- Figure how much sun exposure your garden will receive throughout the day. Just because a plant will tolerate the heavy water conditions doesn’t mean it’s conducive to your light availability.
- Make sure the plants you install will have enough space to grow up and fill in. Rarely do garden centers sell mature plants and if you fail to plan for the growth of your plants it will really damper your garden.
- Grouping plants in odd numbers is a great way to make beautiful statements with color and form. Unless your rain garden will be very symmetrical you should avoid using straight lines with the groups of plants.
- Try and think three-dimensional and use taller plants in the center of the garden with shorter plants towards the border of your garden.
- If you are trying to save money on installing this project consider using younger plants. While the garden will still hold the same amount of water it will take several more years for the plant life to fill in.
- Enjoy getting your hands dirty! This will be a point of pride for years to come, savor the moment.