How to Design a Rain Garden

This week at my practicum, located at the Last Resort Farm, we constructed a new rain garden. My mentor always has a project for us to accomplish each week and this was the most physically intensive one yet. Before arriving at the farm for our normal duties, we were asked to draw up plans for the garden. I found a nifty website dedicated to gardening where I was able to put together my ideas. If you take a look at the picture attached to this blog, you can see how detailed the garden program was.

The main purpose of this rain garden was to help stop runoff water coming from his house and washing away a terraced garden box at the bottom of a hill. Initially, I flagged the ground using an 'A'-Frame to see how the contours fell. Then I marked which way the water flowed down the hill, took some measurements of the area, and started to sketch out my ideas. With water in mind, I made sure that I incorporated plants that require a lot of water into my initial plans, such as blueberry bushes and ferns.

My mentor decided to use one of my rain garden outlines which had three snake-like berms running down the contour of the hill. When the water hits the rocks outlining the berms, the snake-like shape should help slow it down as it goes downhill. We also decided that it would be best if we made the berms into hugelkultur beds. This meant that we scraped the grass off of the ground, made indents in the soil, and laid down blocks of wood before covering it with grass and brushy-like material. The last steps included placing layers of horse manure and cow manure on top of the mounds. The purpose of this last step is that the wood will help sequester moisture and release nutrients into the ground in such a form that the plants above it can thrive.

The rain garden will be an ongoing project and my mentor probably won’t begin to plant anything into it for at least a year so the wood will have some time to decompose. So much work has already been accomplished and I can’t wait to see how the garden turns out. It’s always fun watching your own plans come to life!