Building a Rain Garden

The steps below will give you a good start if you plan to build your own residential rain garden.

  1. Find a location
  2. Measure drainage area
  3. Create a design
  4. Choose the plants
  5. Layout the garden
  6. Dig the garden
  7. Prepare the soil
  8. Plant the flowers & grasses
  9. Mulch the garden
10. Water and arrange downspouts

2). Measure drainage area – If you are building the rain garden in a low spot in your yard (and not depending on your downspout to supply it with rainwater) you don’t have to do any measuring. Just ensure the area receives water regularly during a rainstorm. Some experts feel a low spot indicates compacted soil so it is important to observe the low spot during and to make sure it drains well. You should also do the simple soil and infiltration test.

If you are capturing water from a roof you will need to measure the specific drainage area of the roof that will supply the garden. Multiply the length and width on the area from the corner of the house to a line drawn from the top of the eave. This will give you the square footage of the drainage area. Then you need to multiply that number 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%.

So, as an example, if the section of roof you have chosen is 10’ x 10’ = 100sf x 30% (loam) = 30sf. So this will be a 30sf. garden dug 6” deep. The garden can be made in a dimension of 5’x 6’ or 3’x 10’.