Rain Gardens

Rain gardens are shallow basins that collect rainwater and allow it to soak in to the ground.  They provide an attractive solution to capture stormwater and deep-rooted native plants help the rainwater better soak into the soil.  In urban and suburban settings, rooftops, roadways, and other paved surfaces prevent rainwater from soaking into the ground.  Rain gardens collect storm water, filter it as it moves through the ground, help recharge the groundwater supply, and prevents pollution carried by rainwater from entering our waterways.  Rain gardens are also inviting to butterflies and birds; they provide vital food and habitat for pollinators in urban environments.

Raingardens filter rainwater by removing sediment and absorbing nutrient pollutants from runoff.  Installation of a rain garden can reduce the flow of polluted runoff from of your property, allowing water to slowly move into the groundwater system. The more water you retain on site, the less water flows across the land surface, carrying sediment and nutrient pollution directly into the Wabash River.

There are many ways to design a rain garden and you will need to figure out your property’s needs to decide on a design.  Decide where you are collecting the rainwater from (roof, patio, driveway, parking lot, etc), how the water will enter your rain garden (buried pipe, surface drain, surface pipe, etc), how big it needs to be to accommodate the expected volume of water (use our calculator below!), and what plants can thrive in that habitat (sunny, shady, wet, dry, etc).

Rain gardens are not ponds, will not cause mosquito issues, and should not hold water for more than 2-days.  Native plants help the soil absorb water, but your site needs to have proper absorption rates so you know the water will soak into the soil.  The how-to guides and videos at the bottom of this page will get you started on your rain garden journey!

Rain Garden Maintenance

Native Plants in rain gardens and bio-swales are well suited to the Indiana climate and require no fertilizers or other chemicals.  These gardens still need to be maintained so that the native plants can flourish and absorb storm water.

Spring

• Add new plants to garden. 
• Mulch if needed. Most gardens incorporate a 3″ layer of hardwood shredded mulch during the first year, which helps keep weeds out while retaining moisture.  After your plants establish, the garden should not need annual mulching as the plants should cover the surface of the soil.
• Weeding is crucial early in the season. Gardens should be weeded about once a week to prevent the weeds from establishing. 
• Learn to recognize which plants should be in your garden and which ones should not. 
• If the project was just installed, and there is no rain, water your garden 1-2 times a week to help the plants get established. 

 Summer

• Weed garden once a week. 
• Rain gardens and bioswales do not need to be watered unless the plants are young and still getting established.  

• Leaves can be left in garden, they will break down into soil if left over winter. 
• Leave dead standing plants through the winter for habitat and as a food source for birds and pollinators.  Caterpillars over-winter in leaf debris, and solitary bees over-winter in plant stems. 

• Learn to recognize your plants. By being able to identify your native plants, you will know which plants to not pull out.
• Weed when the soil is soft to be sure all the roots of the weed are removed.
• Start early in the season to prevent weeds from taking over the garden. 
• Use smaller native plants as a “green mulch.”  They can often grow in the shade of taller plants, will protect the soil, and will suppress many (but not all!) weeds.  Some examples of natives that are good for “green mulch” include common blue violets and star sedges.

Local Resources:

• City of Lafayette
  
• Rain Garden How-to Manual
• Purdue Extension Rain Garden Videos

Resources:

• University of Wisconsin Extension Rain Garden Manual 
• Indiana Lake Michigan Coastal Program Rain Garden Manual