How to Create Your Own Rain Garden

Building a Residential Rain Garden 🍃

So, you want to build your own rain garden. Lucky for you, it isn't a painstaking process and once you've finished it, you'll find your yard to be prettier and more efficient than it was before!

Why Should I Build a Residential Rain Garden?

Well, not only is a rain garden a way to beautify your yard, but also a way to employ the use of natural processes by...

• Temporarily holding and soaking in rain water runoff that flows 
• Removing 90% of Nutrients and Chemicals
• Removing 80% of Sediments 
• Draining 12-48 hours to prevent the breeding of mosquitoes 
• Preserving native vegetation
• Providing wildlife habitats for birds, butterflies, and insects

Okay, I want to Build a Rain Garden. Where Should I put it? Where Should I Not put it?

 When you are building a rain garden it is important to keep these points in mind about where and where not to build :

• They should be located in low lying sloped areas so water can pool up in there
• Should be 10 feet from a house or building
• Should be near impervious surfaces like driveways, roads, and sidewalks
• Do not build one over a septic system
• Do not build it if you live in an area where the seasonal high of a water table is within 24 inches of the soil surface
• Do not build next to building foundations

Now That I Know Where and Where not to Put It, How do I build it?

Building a Rain Garden is not as complicated as you may think. You can elect to build it yourself or hire landscapers to build it for you. Listed below is a simplified list on how you should go about building a rain garden:

1. Locate a site that is a natural slope in the landscape
2. Determine the size of the rain garden based on the location
1. For Clay soils the garden should be 60% of the drainage area
2. For Sandy soils the garden should be 20% of the drainage area
3. For Loamy soils it can be sized between 20% and 60%
• It is important to know your soil type by testing the infiltration rate 
• The lower the infiltration rate the larger the garden need to be 
• You can test your infiltration by digging a hole that is 6-8 inches deep and filling it with water and observing how long it takes for the water to drain
• If it takes 12 hours or longer, it isn't suitable for a rain garden
3. Once the garden has been planned it, you can start digging
• Start by removing soil so that the deepest part is about 8-10 inches deep
• bottom should be as level as possible
• extra soil removed should be used on the downhill side of the garden to create a berm
4. Mix organic matter into the soil within the rain garden by spreading 2 - 4 inches of compost over the area and mixing it with the existing soil
• If soil is acidic add lime to neutralize the sample
• For soils with high clay content, remove 1- 2 inches of the soil and put porous rain garden soil
5. A shallow swale or corrugated drain pipe should be set up to carry the water from the roof downspout to the rain garden
• Make sure the ground slopes away from the foundation, so water doesn't pool around it
6. Establish a grass or groundwater border along the rain garden to slow the flow of water into the garden and do the same for the berm to stabilize it
7. Select and plant drought tolerant, wet tolerant, and hearty plants.
• A mix of ornamental grasses, shrubs, and self seeding perennials is a good choice
8. Once the plants are planted cover the garden with a 3 inch layer of mulch 
• Best mulch choices are ones that are pine straws, wood chips, or shredded wood
9. To maintain the garden remove,weeds regularly and replenish mulch as needed.
10. Plan on providing an overflow path in case the rain garden overflows with water.

As you can see building a rain garden, while it looks like a daunting task, can be one that is worthwhile and beneficial to the environment. If you would like to see a real life example of a rain garden and see how it works, you can always drop by the Cobb County Water System's rain garden that is right next to the water quality lab.