It may be renowned worldwide as the city of romance and revered for its beautiful architecture and art but with over 20,000 inhabitants per square kilometer, Paris is also a very crowded place to live. Parisians who want a steady supply of home-grown greens may turn to window boxes, balconies and small-scale vertical farms (like Window Farms perhaps) for help, but where space is a premium such luxuries might not be possible. Local designers Barreau & Charbonnet have come up with a hanging window garden named Volet végétal in which plant containers are raised and lowered on a pulley system rigged up to the outside of an apartment window.

The current prototype consists of a wooden frame that has three pivoted container holders positioned within. Into these are placed plastic window boxes, each containing a layer of clay balls and another of loam, and then topped by mesh that the plants will grow through for harvesting. Barreau & Charbonnet told us that "gravity and the weight of containers keep the crops horizontal." Steel stays are secured in the window frame and strings and pulleys are used to raise and lower the structure like a drawbridge.

The designers say that the 110 x 150 x 120-cm (43 x 59 x 47-inch) system can also be used as a kind of shutter to limit light coming through the window, and can even be brought indoors and placed on a stand in the corner of the apartment. Top heavy crops like tomatoes would probably be unsuitable for this type of system but salads and herbs would seem to be a good fit.

The original wooden-framed prototype seen here was created for the "Jardin Jardin" design contest for Paris residents who don't have access to gardens or balconies, and is said to have been quite a talking point at the recent le Jardin des Tuileries exhibition in Paris. The designers told us that they're currently working on financing and manufacturing strategies to bring a production model to market.

They said that a commercially-available version would have a lightweight but strong aluminum frame instead of wood and a thin metal frame with some kind of mesh to help keep plants from falling out in the event of accidental tipping. Even so, strings are bound to wear down or slip from pulley wheels, brackets can crack or snap as they age, and stays temporarily secured to a window frame could slip or fall - all of which could see flower pots raining down from on high and taking out innocent passers-by.

No doubt such things as redundancy support and other safety measures aimed at ensuring that Volet végétal is capable of withstanding all that Mother Nature has to throw at it will be added during the commercialization process.

Barreau & Charbonnet say that the system could be available to buy as soon as next year through a separate company that's currently being set up to market the system. The cost is currently an unknown but is hoped to be in the €100 (US$126) range.

A short video showing the build process and demonstrating the system in operation follows:

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