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how to create a rain garden over concrete

I'm trying to reduce impervious cover by building a garden over concrete with the proper dainage ~ does anyone know if this can be done or how?

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Posted 2013-12-03T16:52:25+0000  by tiffanir tiffanir

thank you so much for the information


Best Answer

Posted 2013-12-04T16:00:25+0000  by tiffanir

Hi tiffanir,


Thank you for your question and welcome to our community.  To create your rain garden, you may want to consider making raised planter beds.  There are a variety of materials to choose from.  Rain gardens are typically humid and moist but they can also be constructed with plants that are native to your area as they will be more likely to adapt to your particular environment.   


Your first task will be to create a design.  Will your rain garden be on the ground or a roof top?   Weight may be an issue if you are planning a rooftop design.  Cinder blocks make a great raised garden bed as do the oak wine and whiskey barrels. 


Wine barrel raised planter.jpg Cinder block raised planter.jpg


As long as you have the proper drainage, creating your rain garden will just be a matter of figuring out what you want to put where as long as it will survive in your planting zone.  


Since a raised garden is essentially an enclosed planter, you will want to use a potting soil to provide better drainage.  Keep in mind that concrete that is constantly exposed to moisture can develop a black mold that is very slippery when it is wet.  This can be mitigated by regular cleaning with a pressure washer.


Once you have created your design, build your planters and place your wine and whiskey barrels in the desired positions, step back and see if you like the placement.  If not, this is the time to make changes, not after you have loaded the planters with soil. 


After you have confirmed your design, start adding your potting soil.  Once the soil has been added, place your plants in their perspective areas and step back again to get an overall view of the placement of the plants.  This is the time to make changes, before you have planted them.


Once this task has been accomplished, add your weed mat.  This step will help to reduce any weeds that will be blown in by the weather or from critters.  Secure the weed mat with the weed mat staples.  When adding your plants, do not cut a hole into the wed mat, but instead, cut an X in the fabric big enough to put your plants in. Once the plant is in the ground, simply put the fabric back over the base of the plant. 


Weed mat fabric black.jpgWeed mat staples-package.jpgWeed mat staples.jpg


Once your plants have been installed, place a layer of mulch about 2 inches deep over the whole planter bed area.  The mulch will help to keep the moisture in the soil. Your selection of mulch will vary depending on your area. 


After you have finished planting your rain garden, be sure to water about every other day, depending on the weather, for the next two weeks.  The key to a healthy rain garden will be good watering techniques.  


Another way to help you keep the weeds at bay will be to use a "pre-emergence".  The pre-emergence will prevent the germination of a weed seed for up to 3 months.  Check with your local Home Depot Garden Department for further information and product availability.

Preen Weed Preventer.jpgPre-emergence Concern.jpg




This sounds like a very exciting project!  Be sure to document your progress and share it with the rest of the community in our Project Library under "I Did This".


Please let us know if you have any further questions.


This has been another of,

Posted 2013-12-03T20:43:10+0000  by Rick_HD_OC
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