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Here’s how to build a rain garden and how it will help you. A rain garden is desirable for many reasons.
It helps to filter water runoff from roofs, driveways, and other areas.
Planting a rain garden offers an eco-friendly water solution.
In most suburban neighborhoods in developed countries, a common water pollution problem persists.
The fresh rainwater from each storm runs from rain gutters, across lawns treated with pesticides, into dirty gutters, and finally down storm drains into rivers and lakes.
In drought-prone areas — such as in the southwest United States — rain gardens are beneficial to capture the water to help support the water table.
No matter where you live, you will benefit from rerouting rainwater away from your home toward a rain garden with native plants.
Here’s everything you need to know about starting a rain garden.
What is a rain garden?
A rain garden is a sunken garden located along rainwater’s inevitable path.
Rain gardens collect runoff water from different sources, including the driveway, gutters, roof, or patio.
The idea is to reroute this water into an area and fill it with vegetation to establish a rain garden.
If your property slopes, has areas in which rain gathers, or has areas in which gutter and/or roof water flows, choosing this area for a rain garden will be beneficial.
If your home is at the bottom of a hill, rerouting rainwater will be critical.
By diverting gutter water and other areas where water travels, gardeners can help filter water into the surrounding soil in a natural and clean way.
To the casual observer, a garden looks like any other attractive flower bed or garden, when in fact it’s an ecological aide.
There are many rain garden benefits as well.
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Rain garden benefits
There are many benefits to having a rain garden.
You will direct rainwater away from your home, garage, shed, etc.
In the process, you will foster a habitat that will attract butterflies, bees, birds and other wildlife.
Rain water gardens are beneficial as they provide flood control and improve the water quality by filtering the runoff.
How to build a rain garden
Before digging in (pun intended), follow these five steps for rain garden success.
1. Consider your climate
Whether you live in a rainy climate, a dry climate, or a climate with the traditional four seasons, the good news is rain gardens will grow and be helpful anywhere.
The key is in planting your garden with native plants.
Rain garden designs can be successful from Phoenix to Albany and in every climate in-between.
While rain gardens have become extremely popular in rainy areas such as Washington and Oregon, the rest of North America is not far behind.
In fact, several cities, including many in the Midwestern US, now charge a storm drain water fee to suburban residents.
If you’re a homeowner, you can avoid this by diverting your storm drain water.
2. Choose your rain garden’s location
Where to put your rain garden is essential.
After a hard rain, note the direction the rainwater runoff flows and where it pools.
When you come up with your rain garden designs, be sure to note utilities. You won’t want to dig up an area with underground utilities, etc.
Divert water runoff away from your home
You will want to be sure to divert water runoff away from your home and garage. This is important whether or not you plan for a rain garden.
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If you have a yard, also note areas that collect water.
A natural depression in your lawn is an ideal spot for a successful rain garden.
There are trees that soak up water and water-loving shrubs you can include in your rainwater garden plan.
Choosing location for rain garden
You’ll want to place your garden within the path of water run-off or create such a path.
If you don’t have a natural area that collects water, you can make one.
For instance, you can plant a rain garden as a border along your storm drain spouts (at least 10 feet from the house).
Another place that can be successful is adjacent to a garden shed.
If you want to place your garden outside the natural path of rainwater, be prepared to dig a trench.
You may need to lay down a drainpipe to direct your rainwater.
Your rain garden location also needs to absorb water at an ideal rate.
Test potential sites by digging a hole two feet deep, filling it with water, and seeing how long it takes to drain.
The ideal rate is above .5 inches per hour.
Find this rate by dividing the number of inches by the number of hours it takes to drain.
3. Decide how big your rain garden will be
The size of your rain garden will depend on the type of soil you’re working with in your region.
Does it absorb moisture easily, like in the Cascades, or slowly, like in the high desert?
Generally speaking, a rain garden 1/10th the size of your house roof should be able to handle 90% of your runoff.
4. Divide your garden into ringed zones
Your garden will include areas of high water content and areas that remain drier.
This will depend on the direction the water enters your rain garden and how level overall it is.
Going to your local nursery or garden center will put you in touch with experts for plants in your area.
It’s important to consider the rainwater planting zones, putting the lowest water needs/tolerance at the top of the rain garden zone.
Bottom rain garden zone
The inner zone at the center of your garden should be the plants that do best with the most water.
This is the area that even with a small amount of rainwater, the area will fill with water.
These are the higher water needs/tolerance.
This is considered the bottom rain garden zone.
Terrace rain garden zone
Midway on the slope, this is the middle zone.
In this section, you should have plants with lower water needs/tolerance.
This area is called the terrace rain garden zone.
Top rain garden zone
The top of your rain garden is the outermost ring.
This zone is the highest level.
In this section, you should have plants that will thrive with less water than the other sections.
This is for plants with the lowest water needs/tolerance.
This is the largest ring. It’s called the top rain garden zone.
5. Choose rain garden plants
You will want to choose native plants for your rain garden.
Which native plants you choose will depend on your area. Just because a plant is native doesn’t mean it’s the ideal choice for your rain garden.
Plants with deep roots do best but don’t be afraid to add a variety of native plants to your garden.
Many gardeners choose a mix of native seeds which will combine many varieties of grasses and plants. Others may want the vegetation to be more planned out and orderly. Either will work.
Many libraries have seeds that will be native to your region.
There are guides to what native plants will be best for your rain garden. These will take into account the topography, climate, and other considerations.
You should stop in your local garden store; they will know which plants are best for your rain garden.
In addition, you can contact the agriculture division of your local university or community college.
Best plants for water runoff
There are other considerations as well. Are you interested in rainwater plants for shade?
If so, there are a variety of shade rain water plants you can find that will do well in your area.
Perhaps you want to add shrubs for wet areas around your property outside of the rain garden.
It will be important to learn the USDA plant hardiness zone for your area.
It will help you determine which plants can tolerate the maximum and minimum temperatures in your area.
Which native plants will do best
In addition to choosing native plants, you will want to learn what types of plants work best to absorb the most water.
Determine whether you need a drainage system below your garden
This last rain gardening tip may not apply in your situation.
If your budget allows for it, you may want to install an under drain below your garden to carry cleaned water away.
This is important if the soil around your garden is unclean, thereby contaminating your clean water should it drain into it.
If you opt not to add this feature, your garden will be self-contained; make sure the plants you select can withstand excess water.
We saw an excellent display about how to make a rain garden and about rain harvesting at the Discovery Center in Milwaukee if you are ever in the area.
How to build a rain garden
Before you start buying plants, it’s essential to learn how to build a rain garden so you can get the maximum benefit from it.
There are many rainscaping ideas you can choose from.
Selecting the right location on your property and knowing which plants will thrive in your area will be essential.
Even if you are already harvesting rainwater, you can benefit from a rain garden.
How to build a rain garden in your yard
Use these easy steps to make a rain garden.
If you plan for and build your rain garden properly, there won’t be any downsides.
The main concern is how long does it take for the water to infiltrate into the soil.
When you plant a rain garden, the water shouldn’t stand longer than 48 hours so it does not attract mosquitos.
Building a rain garden tips
After following the steps above, you’re ready to get started with your rain garden.
There are many benefits to having a rain garden.
You will redirect water from your house and maximize the standing water in yard after rain.
You will choose plants for wet areas to fix a yard that holds water.
In this way, you will capture surface runoff and create a rain garden habitat for butterflies, bees, birds, and other wildlife.