How to Construct a Green Curtain

The weather in Tokyo seems to be getter hotter by the minute. Tsuyu (the rainy season) is set to finish shortly, and we're preparing for the hot sunny days ahead. Unlike the energizing bright cool winter months, the summer sun paired with high humidity is wilting. Hoping to reduce our desire to run the air conditioner and inspired by a multitude of neighbors with lovely vines full of cool green leaves, we thought we'd grow a green curtain of our own!

Here is how we did it - from thought-process to equipment to construction - and, as usual, a few caveats. This "recipe" can easily be tweaked to suit any situation, but will hopefully be a good starting point for cooling summer days.

The Logic

Nets, vines, and pots abound at the moment in the city, and little tendrils of goya (Okinawan bitter melon), fusen (a flowering vine), morning glories, and even cucumbers wend their way upward. These often fruitful screens do double duty. Their shade prevents sunlight from heating up the space behind - whether for outdoor seating or a room in an apartment or a whole building - and sometimes provide something tasty for the dinner table, too. It seemed like a fun choice to help us keep our cool!

Equipment

• Pots - One big one, a couple medium-sized ones, or medium-small pots for each individual plant. We used one big one set in brackets that hangs off our balcony. This allowed us to position the pot, plants, and netting where it would offer the most shade, and still left room behind for access.
• Netting or a bamboo shade - The plants need something to climb on that can be attached to or strung in front of a window, wall, or whatever area it is to be covered. We choose netting, but many of our neighbors use a combination of the two.
• Dirt - A combination of bagged compost and composted cow or chicken manure should do the trick. I used leftover dirt from other projects, mixed in some bagged compost, and some composted cow manure. If I had to do it over again, I'd add some calcium (ground up seashells, etc.) to give the vines added strength.
• Plants - Just about any vine or tall plant should work. I'd been given some seeds for goya and fusen, and I am also trying out Jerusalem artichoke. The latter should grow quite tall to make a leafy screen that doesn't require netting, etc., and I can still eat it at the end of the season.

The Thought Process

1. Where did we most want shade?

Our apartment gets heaps of sunshine, which we love. However, this also means it gets mighty hot in the summer months. Blocking some of the intense afternoon sunshine coming in one set of sliding glass doors seemed like a good choice for cooling the apartment.

2. How much shade did we want and how much was feasible?

Certainly, we'd like to cover the whole building in a green curtain, but that's not very practical. Based on where we decided shade is most desirable and where the afternoon sun is, we figured out roughly how large of an area we needed to cover. Green curtains can cover just a window, a wall, or the entire side of a building. It doesn't really matter. It simply depends on what you think you can reasonably create. Certainly, the more shade you make the cooler your summer months will be, but your neighbors may not appreciate your vines climbing over their balcony. (Then again, they might!)

3. Edible or ornamental? Vines or taller plants?

Green curtains can be made of anything, really. I'm a big fan of mixing edibles with ornamentals, because both are beautiful and extraordinarily complimentary. Goya (Okinawan bitter melon) is quite popular, but if that doesn't suit your taste buds consider morning glories, fusen, or cardinal climber. (I started mine from seeds I received as a gift, but these are all available at local nurseries, too.) Other edible vines to consider are cucumber, squash, or watermelon. Keep in mind though, that the heft fruits of the latter two will require some support. A simple system of rigging could help hold the fruit in place and keep the vine and netting up, too. My guess is that it would be well worth the effort, though!

Other plants worth considering are tall ones like sunflowers, Jerusalem Artichokes, or yakon. Each of these grows quite tall and would probably provide enough of a screen to make lovely shade. Plus, with the Jerusalem Artichokes and yakon you could enjoy a tasty little harvest at the end, too!

Construction

• Measure the space to be covered. This will help determine the number of plants and pots required to cover the space. Our doors are roughly 170cm wide and 180cm tall. The netting is also about 170cm at its widest point, and 180cm high from its base at the railing to the top.
• Plant the vines. We planted about six fusen and goya vines total (about six plus a cucumber I threw in because I couldn't bear to pitch it) in the pot, and positioned it in the brackets. (See Caveats for a little more detail.)
• Hang the climbing apparatus. We ran twine between a pole just off our balcony and a bracket for the air conditioning unit. We then tied the netting to the same pole and bracket and clipped it to the cross twine. We also ran twine vertically from the balcony railing to a metal loop on the roof. (No, we don't know why there's a metal loop on the roof.) This will offer additional support as the vines get bigger and heavier with leaves and fruit. I should also mention that we cut our net in half so it would cover from the topmost point to below the railing.
• Gently train the vines to start clambering up. The vines won't need much training, but they do surprisingly have their own ideas at times about where to go. Check on them daily for awhile to make sure they're heading up and not venturing onto other plants or just winging wildly in the air.
• Water. Container plants tend to dry out rather quickly. Drooping leaves mean thirsty plants. If the container (like ours) is suspended out a bit, make sure extra water will not drip on a downstairs neighbor, their laundry, or airing bedding. If the container(s) simply sit on the ground, position saucers underneath that will hold excess water. The plant will just absorb it later.

Caveats and Ideas

I've also seen green curtains used to create an arbor of sorts for outdoor areas, or to keep a wall from getting too much direct sunlight. Based on this year's experiment, we'll refine things for next year and put one up on our front balcony to help block light from our front door and a bank of wall that soaks up the intense morning light.

We planted the vines well before we put up the net. While I don't necessarily recommend doing that, there are some benefits. While the top of the pot looks like a tangled mass of vines (Ok, it is.) it's created a sort of self-mulching effect that keeps the pot from drying out too quickly. The real test, of course, will be in the upcoming months as temperatures increase and rainfall drastically decreases, but I have high hopes.