Case Study – Rain Planter in a Domestic Courtyard

To demonstrate how a rain planter can transform a small space – creating an attractive feature while managing rainwater sustainably, let’s take a look at case study:

Location:
This rain planter was installed in a tiny domestic courtyard – sandwiched between two glass door/windows and 2 stone walls.
It’s to the side of a busy front entrance hall to a family home so it’s seen frequently throughout the day and is one of the areas guests first see when they enter the house so, it needed to look good!

There were 2 possible down pipes that could be used but for ease of access we used the one carrying the water from a combined roof area area of approx 15m2.
Using MET office data for the area we can calculate the average expected rainfall per month of approx 950 litres.

Due to the constrained space we chose a 50cm3 Corten steel planter as our container. If it was just filled with water, the total volume of this would be 125l. However, we assume approx 2/3 of this is taken up by the aggregate for drainage and compost for planting at any given time.
So, you can see that it’s important, especially for smaller planters, to have an effectively working through and over-flow system.

As this particular feature was intended for a shaded courtyard area, we focused on planting that would be tolerant of the shady conditions as well as periods when it would be quite dry (along with the occasional deluge!)

Construction:
The existing drainage hole in the bottom was plugged up and the planter was positioned in the courtyard. The down pipe was connected via an overhead half round guttering pipe feeding water to a rain chain to the planter in this instance.
(The intention is that the plastic guttering be replaced with some reclaimed metal guttering in due course to complete the feature).

The outlet here was a hole drilled into the bottom of the side of the planter and a smaller, overflow pipe directing the excess water back to the drain at a much reduced speed and rate, connected.

The pipe is then to be hidden under the gravel and the pipe secured into the drain grille for neatness.

Planting:
Once filled, we added a selection of plants suited to the shaded, sheltered environment of the courtyard. We chose plants known for their ability to thrive in low light while also being tolerant of occasional wet conditions.
However, whatever the conditions you are working to, pick plants that will be suited and have the best chance of thriving.
Healthy plants are much nicer to look at and much better for supporting wildlife.

Here this mix of plants creates a balanced, water-efficient planting scheme that grows well in the shady courtyard, while also helping to draw up some of the rainwater that collects in the planter.

We used:
Heuchera Palace Purple
Lizula nivalis
Carex Irish Green
Polystichum setiferum
Hedera helix (ivy) – a cutting from the surrounding walls

How it’s going:

It works!

We are seeing a good volume of water enter the planter and a reduced amount leaving it during and shortly after periods of very heavy rain and we’re happy that the overflow pipe works.

The planting has settled in well and is starting to show some signs of growth. As it was planted last Autumn, most of the establishment is going on under the surface at present but, we’re expecting it to start romping away, come, Spring!

It’s definitely lifted this small space, creates an unexpected feature that is seen as soon as you enter the house and it’s lovely to hear the sound of the rain falling during heavy downpours!

Key Takeaways:

Rain planters are a small space, big impact features and, even in a small, shady spaces, can make a huge difference in:

• Capturing and managing rainwater effectively
• Increasing biodiversity
• Offering new spaces for planting
• Creating interest and looking good
  

They are also sustainable and require little maintenance: With the right materials and plant choices, a rain planter is easy to install and maintain, offering long-term benefits with minimal effort.

You can create your own to help manage rainwater in your garden, no matter the size or shape of your outdoor space.

It’s an effective, easy-to-implement feature that’s good for you and your local environment as well as supporting local wildlife and a perfect addition for homeowners looking to make a positive impact.