Rain gardens
Rain gardens are garden beds that are designed to absorb and filter stormwater. There are rain gardens in public parks and home gardens. Together, these rain gardens slow the flow of rainwater and clean it before it goes into the stormwater drains and our lakes. You can create a rain garden with a few materials and careful choice of plants that can handle getting wet. Once established, rain gardens are attractive garden features that are self-watering and easy to take care of.
How rain gardens work
When rainwater run-off is directed into a rain garden, it sinks into free-draining soil to feed the plants. The garden filters out dirt and pollution before the rainwater flows into buried drains. Leaf litter and sediment (and the nutrients they contain) stay at the top, and the plants use many of the nutrients dissolved in the rainwater.
Build a rain garden
Your rain garden can be positioned to harvest water from the roof or from a rainwater tank overflow, simply by extending a downpipe. They can also work where rainwater flows off paved areas. The rain garden can be a planter box (under a downpipe), a trench in your yard or even just a small depression. You might need a liner around the edges to keep things dry if it is near a building or if the ground is too wet.
If you're building an in-ground style of rain garden:
- slope the area away from your house
- make sure the soil is free draining to prevent permanent waterlogging
- place some rocks in the lower sides to prevent soil from washing away during heavy rain.
Keep your rain garden healthy
A healthy rain garden will need:
- free-draining soil that can soak up water but also lets it pass through
- plants that can handle lots of water sometimes, and not much water at other times. Native plants are best because they're used to the local weather and are easy to take care of
- several different types of plants to out-compete any weeds, and regular weeding until the plants have grown and expanded across the garden
- gravel as mulch on top to lock in the water and stop it from washing away the soil
- a wide outflow area, so heavy rain doesn't wash everything away
- hand watering until your plants have established
- protection from foot or vehicle traffic, to prevent soil compaction.