Rain Garden Design Series: Part Three, Installing Your Rain Garden

In our last Watershed Landscape post, Rain Garden Series Part Two, we provided simple steps to calculate the size of your rain garden, calculate how deep it should be, and provided some examples for planting design.

Today’s post will cover the last part of your rain garden- installation!


Tools/Skills Needed: Flagging stakes or ball field paint, shovels, rakes

Costs: Varies, depending on the size of your rain garden

Time: 3-6 hours

 Level of Difficulty: Easy to Medium


Ordering Materials

With your design calculations, you should have an idea of how much soil amendment, plants and mulch you will need. Additional materials might include rock, decorative rock bordering, landscape edging or gutter extensions and irrigation supplies such as drip hoses, depending on your project.

Most places will deliver materials for a fee or you can pick them up from your retailer. Many landscape nurseries carry all of the supplies you may need for your convenience. Check out this list of suppliers in our area that can help you with your rain garden order:

White River Nursery, Fayetteville, Ark.  Phone: 479-442-2061

Janie’s Greenhouse, Gentry, Ark. Phone: 479-936-1498

Westwood Gardens, Fayetteville and Springdale, Ark. 479-442-3500

Ozark Gardens and Nursery, Inc., Tontitown, Ark.   Phone: 479-306-8733

Chev’s Trucking and Topsoil, Cave Springs, Ark. Phone: 479-313-2176

Nitron Industries, Johnson, Ark. Phone: 479-587-1777

Stone Gardens LLC, Lowell, Ark. Phone: 479-659-0008


Rain Garden ExcavationExcavate your rain garden to allow for storm water to soak in!



To prepare your garden area for excavation, you will want to mark out the outline on the ground with either ball field spray paint or stakes, whichever is best for you. This will give you the boundary for digging. To excavate, there are several options. Depending on how large or small your garden may be, taking out soil can be done with a tiller and shovels, or you may want to hire a contractor to dig the area for you. There are many local contractors that can help with small jobs, expect to pay anywhere from $60 to $90 per hour for their services.

Also, be sure your site is clear of underground utilities; Arkansas One Call (dial 811) will send a representative to locate your utilities for free.

Prepare to have your rain garden materials at your site prior to excavation. If you have a large area, the contractor can place the materials for you! For smaller sites, after the area is excavated to your calculated depth, you can place soil amendments in with a wheel barrel. Also, keep in mind that although the rain garden depression depth is 6-8” deep, if you are amending the soils, that will need to be accounted for during excavation. For example, if your calculated depression came to 6” and you are wanting to add in 8” of amended soils, the total excavation depth will be 6” + 8” = 14” deep. That ensures that when you add in your 8” of soils, you will still have a 6” depression that allows for holding the stormwater in the rain garden.

If you are taking soils out, plan for where the excess material will go. Will it be hauled away? Can it be placed in low spots on your property? Planning ahead of time for these types of decisions will help the installation to run smooth!



Building a berm on the downhill slope will help keep water in the rain garden.  Shown is the Cave Springs Community Building Rain Garden.



Building the Berm

In order to keep stormwater in the rain garden for a period of 24 to 48 hours, a berm should be constructed to hold water in. The berm should be compacted soils and placed on the downhill slope side of the rain garden. The top of the berm should be level with the uphill side of the rain garden and not exceed 18″ wide. In case of a large storm event, design an overflow into the berm so that water is able to escape and continue to its original destination.


Planting the Rain Garden

Planting your new rain garden can be a fun event, invite friends and family to help! Cave Springs 4-H and volunteers from Sam’s Club help plant the Cave Springs Rain Garden.



After your rain garden is excavated and soil amendments are added (if needed), you will be ready for placing plants! It is good to place the plants while still in their pots and play around with the arrangement until it meets your desired look. This can be a really fun activity for kids, neighbors or friends to help with, make it an event!

After planting your plants, place a 3-4” layer of mulch on the entire rain garden and give the plants a good drink of water to help with the transplant. You will want to water the rain garden daily for the first two weeks, and should provide watering on a regular basis for the first growing season while the plants are establishing.


Weeding & Mulching

All rain gardens need occasional weeding and replenishing of mulch. As the garden matures, weeds will be pushed out by the growing plants. The mulch will need to be raked periodically and replenished or freshened next spring and each spring after that.


Rain Garden Academy

Come learn more about rain gardens and help plant them at our Spring Rain Garden Academy! Shown- Bentonville volunteers plant a rain garden at the Bentonville Public Library.


Spring Rain Garden Academy

We look forward to hosting another Spring Rain Garden Academy! This event will be held on Friday, April 11 at Carroll Electric in Huntsville, AR. This workshop will provide both classroom and hands-on training on how to design and install a rain garden. Participants will get to help plant one of five rain gardens during the training. Registration is required, sign up today!


Related Posts:

Watershed Landscape: Rain Garden Design — Part I

Watershed Landscape: Rain Garden Design — Part II

Watershed Landscape: Rain Garden Pre-Spring To-Dos

Watershed Landscape: Rain Gardens, A Blooming Good Idea!