Build Your Own Rain Garden
What is a Rain Garden?
A rain garden is designed to catch rainwater and slow,
decrease and improve the quality of storm water runoff.
A rain garden can take many different forms and, for the
most part, is limited only by the resources and time you
have to put into it. It can be large, complicated and
expensive – or small and relatively simple. The
rain garden design described here step-by-step, is inexpensive
and easy. This rain garden project would work just as
well at a home, school, community center, religious center
or any other private property. Waterways in Kentucky are
severely affected by nutrient and sediment pollution.
Here is something you can do about it!
Why Create a Rain Garden?
Virtually every home has a substantial amount of impervious
surface (area that rainwater cannot soak into), which
affects the quality of storm water runoff. When rain lands
on an impervious surface, it cannot soak into the ground
and eventually enters a storm drain or a nearby creek.
This excess water (called runoff) causes the soil in its
path to erode more rapidly than it would naturally. Gravity
then causes this runoff to flow downhill and into the
closest stream or other waterway, carrying with it the
sediment, pesticides, fertilizers, and other pollutants
it encounters along the way. Rain gardens contain plants
that intercept and slow down the storm water runoff and
absorb or trap much of the pollutants it may contain.
Rain gardens also restore wildlife habitat by attracting
creatures such as insects, butterflies, toads and predators
like hawks.
Choosing a Location
The most important aspect in choosing a good spot is figuring
out where the rain garden is needed most. Deciding where
to put your rain garden can be almost as fun as building
the rain garden itself. Your goal is to find places in
your yard where rainwater regularly runs off of an impervious
surface, such as a downspout from the roof, a hardened
footpath, or a basketball court. Where does that water
go? You should position your rain garden between the source
of the rainwater runoff and the nearest waterway or storm
drain. A great way to really see what happens to runoff
on your property is to walk around the yard while it is
raining.
Choosing your Plants
One factor that will determine how much money you will
need is the plants you choose to put in your rain garden.
Depending on when you build your rain garden, you may
use potted plants or seeds. For expert advice, the U.S.
Fish and Wildlife Service offers an excellent booklet
called Native Plants for Wildlife Habitat. Locally, the
Kentucky Department of Fish and Wildlife Resources will
give out free expert advice about choosing the right plants
for the rain garden. Call Mary Carol Cooper at 502/564-7863.
Whatever plants
you choose, they should be able to withstand periods of
heavy water as well as times when there isn’t much
moisture at all. Native plants are accustomed to the conditions
in your area, so using native plants will greatly increase
the chance of your garden’s survival. Native plants
are also great for attracting local wildlife.
Materials List
| • |
Three
section of 2X12 #1 treated pine (lengths depend
on the size of the rain garden you plan to build)
– about $15 for one eight foot board |
| • |
Ten two foot long
sections of steel reinforcing bar (re-bar) –
about $10 |
| • |
Two stainless steel
elbow brackets with four 1.5 inch stainless steel
wood screws – about $15 |
| • |
Screwdrivers and
hammer – about $20
|
• |
Shovels and rakes
– about $100 |
• |
Topsoil – about
$3 for a 40 lb. bag |
• |
Mulch or straw –
about $3 for a 30 lb. Bag or $5 for a bale of straw
|
• |
Sand – about
$5 for a 20 lb. bag |
• |
Plants – last
but not least, plant costs will vary greatly depending
upon the quantities and varieties you choose |
Getting Started
| 1. |
Decorate
your Boards
Before you start building, you may want to decorate
the sides of your 2X12 boards. You can paint pictures
of the plants you will grow, of the animal that
might use your rain garden for habitat, or maybe
even a picture story showing how a rain garden helps
to keep our streams and rivers clean. |
| 2. |
Dig Your
Rain Garden
To determine how large an area to dig, outline the
area that you want your rain garden to cover with
the 2X12 boards to get an idea of your garden’s
size. Use your shovels to dig up the top layer of
dirt and grass inside the outline you made with
the 2X12 boards. Turn the soil over so you can’t
see the grass – this is a very important step.
If you don’t turn the grass over it may grow
up through your rain garden and compete with your
native plants for water and nutrients. Use your
shovels to break the big clumps of dirt apart. This
will make it easier for your native plants to take
root. If runoff is heavily focused into your rain
garden, you may want to place some gravel at the
source of the runoff so young plants do not wash
away. |
| 3. |
Build
the Frame
The frame, built with the 2X12 boards, will provide
a wall to keep your soil and plants in the rain
garden. The bottoms of the boards should be buried
about one or two inches in the ground to keep the
soil inside from coming out underneath. The frame
needs to be fairly level, so you will have to adjust
how deep the boards are buried in the ground depending
on the slope of the earth where you build your rain
garden. Use the stainless steel elbow brackets and
screws to fasten the corners of the boards together.
Hammer the pieces of re-bar into the ground against
the boards of the frame. Alternate the pieces of
re-bar on the inside and then the outside of the
frame every two to three feet. Hammer them down
so they are below the top of the frame. You will
then need to fill in the frame with topsoil up to
two inches from the top of the boards. |
| 4. |
Plant
Your Rain Garden
Now you are ready to put your plants or your seed
in the rain garden. If you are using potted plants,
you will need to dig holes in the soil of the rain
garden deep and wide enough to hold the roots of
the plant. Spread your plants around so they cover
the whole rain garden. Be very careful not to compact
the soil, which may cause the plants to have trouble
rooting. If you are using seed, mix the seed with
an equal amount of sand first and then broadcast
it evenly around the whole rain garden. Whether
you use potted plants or seed in you garden, be
sure to put down a layer of mulch, like pine bark
strips or straw. The mulch will keep in moisture
and protect your plants/seeds from weeds. Finally,
water the rain garden thoroughly.
|
5. |
Maintain
and Care for Your Rain Garden
Now that you have successfully planted your rain
garden, all you have to do is take care of it so
it will do what it is supposed to do. Because the
native plants you chose can tolerate periods of
dry weather, you won’t need to water unless
it doesn’t rain for a long time (two to three
weeks). Make sure to pull out weeds periodically
so they do not compete with your plants. |
Congratulations!!
You’ve just built your very own rain garden and
you know how it will help protect our streams and rivers
from storm water runoff and restore wildlife habitat.
If you have any questions
and or comments please feel free to contact the Bluegrass
PRIDE office at 866/222-1648 or by e-mail at prideinfo@kentuckypride.com
Adapted from the
publication Build Your Own Rain Garden, produced by the
Chesapeake Bay Foundation.
