Rain gardens help you and the environment

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By Susan Brown, County Extension

Plant selection and bed preparation enables rain gardens to tolerate periods when the soil is saturated as well as periods of dryness. A rain garden differs from other gardens in the amount of time it can remain flooded and still thrive. 

As gardeners in the South well know, when it comes to rainfall, its feast or famine. These extremes can make gardens a constant challenge, but also makes our region a perfect environment for rain gardens.

A rain garden is designed to capture rainfall flowing through your yard, store that water to nurture its plants, and cleanse runoff, removing pollutants that it carries from various sources. 

Pet waste, fertilizers, insecticides, herbicides from lawns, gasoline and oil from vehicles and heavy metals are all found in stormwater runoff. In a rain garden, pollutants can be absorbed by plant roots and either held in the plant or used by the plant for growth. 

Rain gardens are fairly easy and inexpensive to create. They have a defined structure made up of five basic components. First, observe your yard during a rainfall event. Determine where water begins flowing and where it is going.

Rain gardens should ideally be placed between the source of runoff (roofs, driveways) and the runoff destination (drains, streams, low spots). A natural depression in the landscape works well. The garden should be at least 10 feet away from the foundation of your home. It should be 25 feet away from a septic drain field. The best location for the garden will be in partial to full-sun.

Rain gardens work best in well-drained soils, but they can also be installed on sites with components of clay. 

Pick a few places and dig a 2-foot deep hole, fill the hole with water a few times. Time how long it takes for the test pit to drain. A quick draining garden will drain in 12 hours; a standard rain garden will drain in 12-72 hours; a wetland garden will drain in three days. 

The next step is to determine the size of the rain garden. A depression is created, either by berming a sloped area or by digging down 3 to 6 inches and piling soil around the edges of the garden. The garden does not need to be excessively deep, only deep enough to capture a significant amount of water.

The fourth step is to rototill the bottom of the basin, working in an inch or two of compost. 

Organic matter increases the soil’s ability to absorb and drain water and is vital to soil health and its ability to support plant growth.

Lastly, select drought tolerant or wet-tolerant plants based on how your soil drains so you are working with nature instead of against it. 

Tuck the plants in three inches of hardwood mulch and irrigate during long prolonged dry weather through the first growing season.

 All the water our planet will ever have is already here in some form. It is a finite resource, and gardeners everywhere can play an important role in protecting it.