Rain garden – eco friendly way to save water
With the steady rainfall the city received in the last few weeks, Review spoke to an avid gardener to find out how best to utilise excess water in their gardens.
POLOKWANE – Rain gardens are a great idea for water scarce countries such as South Africa and in places such as Polokwane, gardening centers advise people to create water wise gardens, these include dry gardens and rain gardens.
“Rainwater tanks can have their overflow pipes directed to a rain gardens, making maximum use of any available rainfall will help save water in times of water restriction,” Gladys Gaffane, a qualified horticulturist at Greener Tidings tells Review.
She says rainwater harvesting has environmental benefits, adding that each year liters and liters of storm water is washed off our roofs, driveways and roads when it rains. This storm water contains many harmful pollutants such as oil, litter, animal droppings, organic matter, nitrogen and phosphorus, and it enters our rivers, creeks and bays untreated via storm water drains. Nitrogen can cause excessive growth of algae, which leads to reduced oxygen levels in the water. Algal blooms threaten animals, plants and fish living in our rivers.
“Roof water, particularly in the city, is known to contain a range of pollutants. Some of these include heavy metals (such as zinc, lead, copper and cadmium). Other pollutants include phosphorus and sediments such as dust, dirt and animal droppings. Many of these pollutants are harmful to human health and to our rivers,” she said.
There are many benefits to building a rain garden bed in your own backyard.
Rain gardens are easy to maintain and conserve water, especially if planted with native, drought tolerant plants. They help to filter storm water before it enters our rivers and creeks and help reduce the amount of storm water that enters rivers and creeks after heavy rain and can make a real difference to the environment and contribute to healthy waterways.
How to build a rain garden bed
First, you need to purchase a Rain Garden Installation Packet available at any nursery in the city. Then do the following:
1. Find a location
Place the garden bed at least 10 feet away from your home to prevent flooding in your house. You should try to choose a naturally occurring low spot in your yard or position the garden where your downspouts or sump pump outlet can be used to direct rainwater into your garden.
2. Ensure the drainage area receives water regularly during a rainstorm.
If you are capturing water from a roof or other hard surface you will need to measure the specific drainage area of that surface and multiply it by the number associated with the type of soil you have. For sandy soil multiply by 20%, for loam, use 30-35% and for clay use 45-60%.
3. Create a design
Whether your garden is large or small the same basic principles apply. By planning your garden bed on paper first, you will be able to create the best appearance possible for your rain garden bed. Create a rain garden plan and group plants in odd numbers.
4. Choose your plants
Native plants are suggested for rain garden bed installations because they are best adapted for our climate.
5. Lay out the garden
Lay out the shape and boundary of the garden bed based on your design.
Before you start digging, contact your local (usually non-profit) organisation that locates underground utilities.
6. Dig
Remove the turf grass and dig your garden bed approximately 4-8 inches deep. Use the soil to build a berm around the edges if necessary.
7. Prepare the soil
Amend the soil with 2-3 inches of compost. Mix well.
8. Plant the flowers and grasses
Follow the design you created and place your plants in the approximate positions. Step back and look at the garden and the design. Plants should be placed about 30 cm apart. Once you are satisfied you can start planting the flowers and grasses using a hand trowel.
9. Mulch the garden
Use coarse, fibrous, shredded wood chips that won’t float or blow away. Apply the mulch about 4-6 cm deep. This will help to keep the moisture in and the weeds out. Avoid cypress mulch because it is made by chopping down rare, old-growth cypress in wetlands.
“After you have planted the garden, water it every other day for 2 weeks if it doesn’t rain until your garden looks to be growing on its own. Good water techniques and maintenance is the key to a quality rain garden,” Gaffane says.
