Gardeners, we know how exciting the spring season is. It’s a time to be outdoors, perfecting your yards with lush, colourful flowers and greenery. But those ugly, boring rainy days put a damper on your plans. Not anymore! Transform your garden into one that needs those otherwise ugly rainfalls. Contact one of our landscaping and design contractors to help make it happen!
Spring is a good time to plan a garden. But here’s another type of garden to consider – a rain garden. This planted or stone-covered bed is a shallow depression in your yard that catches stormwater and allows it to be slowly absorbed into the soil.
Here’s how it works
- In the natural hydrologic cycle, stormwater – and this includes snow and ice as well as rain – slowly infiltrates into the soil.
- There, it is naturally filtered and cleansed of some pollutants, is used by plants, and replenishes the water table.
But stormwater often pours off roofs, driveways and other hard surfaces and travels unfiltered into the municipal storm sewer system as well as streams and lakes. Municipalities are increasingly designing their stormwater systems to mimic nature, using wetlands and other methods to protect water bodies. You can do the same on a smaller scale with a rain garden.
This neat infographic tells you exactly how it works:
Why your yard needs one
Relatively easy and inexpensive to design and build, rain gardens can be naturalistic or more manicured, can include a variety of plants, and can be in various shapes. When planted, they can also provide habitat for birds, butterflies and other fauna. Building your rain garden in full sun or partial shade will let you choose the widest selection of plants, but rain gardens can be built in full shade or even among the trees. In other words, they’re pretty versatile!
Finding that perfect location
To find a suitable location for your rain garden, observe how stormwater runs in your yard. Here are the requirements for one:
- An existing depression in your yard could function as a natural rain garden or you can dig out a depression if your yard is relatively flat and evenly drained.
- The depression will need to be shallow enough to ensure that water will not stand for more than two days, but deep enough to hold the anticipated amount of water. A general guideline for depth is 7.5 cm (3 in.) in soils with relatively low infiltration rates and up to 15 cm (6 in.) in soils with high infiltration rates.
- It is important that the rain garden does not create drainage problems on your property or neighbouring ones.
Ready to get digging? Take a few minutes to watch this video. It’ll tell you what to look out for when digging up that depression:
Not a visual person? The CMHC offers an in-depth guide on determining the depth and size of your rain garden.
If the thought of digging up your own garden frightens you, not to worry. We can put you in touch with landscaping and design contractors who can help transform your backyard to make it suitable for a rain garden.
If you have a few extra minutes, consider watching this video. It features other helpful tips that will guide you in finding a suitable location for your future rain garden:
The science behind building one
Determining the ideal depth and size for a rain garden is not an exact science, and various authors suggest different methods. Your rain garden will likely function well if you make a reasonably accurate estimate of the two most critical factors: how much stormwater will be captured, and the soil’s ability to absorb. To see how well your soil works, you can dig a small test pit, fill it with a known quantity of water and observe the time it takes for the water to be absorbed. For precipitation data, contact your municipality or Environment Canada.
The best time to build a rain garden depends on whether you are using plants or seed. Mid-spring after the thaw is the ideal time to put in plugs or potted plants, when the soil is most likely to be moist and fairly easy to dig – and the plants will benefit from spring rains. You can build a rain garden in summer, but you may need to water the plants until they are established. Seeding the bed can be done in mid-spring or late fall. A landscaping and design contractor can provide a helpful guide during a consultation.
Ready to get building? This neat video shows you exactly how to do it:
The right plants for your rain garden
The key to a great rain garden is, of course, the right plants. Below is a list of suggested plants you should be using for your rain garden and how much they cost. Note: this is simply an estimate! Visit your local nursery for price points and materials!
Maintaining a rain garden involves keeping the soil moist during the first growing season, regular weeding for the first two or three years, and the occasional aeration. If there is a heavy rainfall, there may be the occasional overflow of your rain garden, which is designed for average annual precipitation levels. If the overflow does need to be corrected, simple solutions include installing an in-ground perforated pipe or shallow swale that is directed towards a less vulnerable area, or widening or deepening the rain garden.
Once established, your rain garden should provide many years of enjoyment with little maintenance. You can derive added satisfaction from knowing you are contributing to a healthier natural environment. To find out more, CMHC has an About Your House fact sheet, called Rain Gardens: Improve Stormwater Management in Your Yard.
Ready to get gardening? Take a trip to your local nursery and speak to the experts about what you need to get started. Our landscaping and design contractors directory features both professional landscapers and nurseries. Use these tools and you’ll have a beautiful rain garden in your backyard in no time!
About the Author: Christina Haddad is the vice president of Ontario’s Canada Mortgage and Housing Corporation division.