Building a green curtain in your own backyard

Suiken Create Inc.’s newly constructed green curtain at Kitakuritsunishiukima Elementary School in Tokyo.
Suiken Create Inc.’s newly constructed green curtain at Kitakuritsunishiukima Elementary School in Tokyo.

What is a green curtain?

Green curtains are plant installations on the side of buildings that have become commonplace in Japan over the last several decades. By 2012, over 80% of Japan’s prefectural and city governments were supportive of and implementing green curtains within their cities ('Green Curtains' Spread Nationwide). These plant installations serve two purposes: to add some greenery to generally urban areas, and to combat the heat island effect. In short, heat islands are “built up areas that are hotter than nearby rural areas”, and these areas generally experience higher energy demands and air conditioning costs during the summer, in addition to higher air pollution and greenhouse gas emissions year round (EPA). Plant installations such as green curtains are effective tools to mitigate this heating effect because they utilize photosynthesis, i.e. the plants take in sun rays that would otherwise be absorbed by concrete and asphalt.

Green curtains can be built in both industrial and residential areas. Industrial green curtains are most often constructed using steel frames directly attached to a building and ivy. Green curtains in industrial areas often stretch upwards of 20 feet. Residential green curtains, on the other hand, are relatively short in height, usually being constructed to be 5-10 feet tall. Vegetable plants, such as bitter melon and cucumber, are often the main growers on residential green curtains. Residential green curtains only take a few materials and are generally simple to set up, so you could make one in your own backyard!

Green curtains on the side of Tokyo Sky Tree Mall
Green curtains on the side of Tokyo Sky Tree Mall.
Green curtain in Akihabara, Tokyo areaGeen curtain in Shibuya, Tokyo area
Left: green curtain in Akihabara, Tokyo area. Right: green curtain in Shibuya, Tokyo area

 

Building your own green curtain!

 Materials needed:

  • Stretch of soil close to your building wall, OR planter pots that can be situated close to your building wall
  • Netting (trellis netting is a great option!)
    • Length of the netting should be at the height limit you want for your green curtain
    • Depending on the plant species and location, string may also work as the climbing support system (see photo under "Building Steps)
  • Vine variety seeds/young plants
    • Good options include: ivy, jasmine, cucumber, morning glory, pole beans
  • 2 or more poles/stakes that can be secured within soil
    • Length of the poles/stakes should be at the height limit you want for your green curtain
    • Even if you are thinking of attaching the top end of the netting directly to your building, these poles will serve as frame support
  • Optional: hooks that can be installed onto your building (if you want to attach the netting the the underside of your roof or side of your building, but do not have already-installed supports)

Building Steps:

Green curtain in Niigata
Green curtain in Niigata

Constructing a green curtain is relatively easy, but it is important to note that green curtains should be constructed at the beginning of your plant species of choice’s growing season because a green curtain is most effective when the plants have the most time possible for growth.

  1. Prepare the soil for planting
    1. Follow the instructions for the specific plants you are planting, such as digging a hole to a specific depth
    2. For planter pots or for low-nutrient soils, fertilized or nutrient-rich soil can be bought from almost any store with a gardening section
  2. Setting up the netting so that the bottom edge is reachable from where your plants will begin growing, and attach the netting to your preferred supports
    1. Support may come from the stakes/poles, and or from the building itself (in the form of hooks or the actual building wall)
    2. Netting setup example:
      Green garden in Shibuya, Tokyo
      Green curtain in Shibuya, Tokyo area
  3. Plant your plants of choice
    1. Depending on the plant species, it may be most effective to carefully tie the plant stem to the green curtain instead of letting it grow freely
  4. Continue care to help them grow
    1. Water them regularly (unless you live in a rainy area), and add fertilizer as needed
  5. Enjoy your green curtain!
    1. Here are more examples of what a residential-style green curtain may look like:
      Green curtain in Asakusa, Tokyo areaGreen curtain in Niigata

      Left: green curtain in Asakusa, Tokyo area. Right: green curtain in Niigata

Ways to learn more

This article’s focus was to show how one could build a green curtain in their backyard, and could not cover the full history or cultural context of green curtains in Japan. if you are interested in learning more about the history and context behind green curtains’ widespread use within Japan, the following articles are a great start! (articles organized by date published)

Acknowledgements

Thank you to the Carson Undergraduate Research Grant for making Claire Verstrate’s research project, “The Feasibility of a Green Curtain on the Willamette University Campus” possible.


Thank you to Suiken Create Inc. and the Kawagoe Municipal Government for meeting with Claire Verstrate and giving their experiential knowledge about green curtains.


Thank you to Dr. Joe Bowersox from the Willamette University Environmental Science Department and Dr. Miho Fujiwara from the Willamette University Japanese Studies Department for supporting this research.


Photo Credit: Claire Verstrate, Anna Landgren