Whereas the majority of vertical farming concepts and projects featured in Gizmag over the years have either been huge dedicated structures or add-ons to existing buildings, the Windowfarms system downsizes and personalizes veggie growing by placing an indoor farm in the window. The original plastic-bottle-based, do-it-yourself hydroponics system design has been available for a while now but the developers are getting ready to make a new, improved kit version available.

The Windowfarms system was first developed by Britta Riley after reading an article in the New York Times about growing your own food. Living in a Brooklyn apartment building somewhat limited the amount of space on offer to the urban farmer so Riley began working with Rebecca Bray on a vertical hydroponics home farm system capable of year-round growing in almost any window. The first system was made using recycled plastic water bottles, had an upper and lower reservoir that funneled nutrient-enriched liquid down through martini cups to the plants below, and produced 25 plants. An early version of the now fully developed system was set up as an art installation at the Eyebeam Center for Art and Technology in early 2009.

The Windowfarms indoor farm allows the crops to take full advantage of the light available at the window, assisted by personal living space climate control, and regularly feeds the roots with organic liquid soil. After home build plans were shared online, a community of window farmers soon began to share tips and tricks, offer advice to new farmers and develop new ideas. Two or four column systems were subsequently made available to buy as kits. The basic Windowfarms kits contained almost everything needed to start an urban farm in which almost any small food crop could be grown - including kale, lettuce, strawberries, herbs like basil and stevia, peas, swiss chard, cress and even squash.

Buyers would need only supply their own recycled plastic bottles to serve as planters (although bottles could be supplied at no extra cost if required). To meet the growing demand for the kits, Riley employed the skills of New York City trash hunters to get hold of the bottles, offering a higher fee for their finds than the local recycling facilities. The project also worked with the Mid-Hudson Workshop for the Disabled in reshaping the bottles for use as plant containers.

The Windowfarms system design has gone through many modifications since the first prototype made from a few leaky buckets and towers of bottle planters. Each design has been getting easier to set up, has increased production capacity and become more energy efficient. Now the project is getting ready to enter the next phase in its development.

The new Windowfarms kits will be made from BPA-free, food-safe, recycled plastic and wire and instead of taking up to a full day to build and install, the new kits can be up and ready for action in as little as ten minutes. Gone are the recycled bottle planters, having been replaced with environmentally-friendly molded plastic holders, and the various components now just snap together - no more zip ties, sewer pipes or dowel support spines. An air pump still sends up a burst of nutrient-rich liquid to the top of the tower at regular intervals - controlled by a timer - and the liquid trickles down the column, feeding each pot on its way down, with the surplus returning to the reservoir to be re-used.

An active online Windowfarms community of over 22,000 global members is available to help new window farmers get the best from the system, although users won't be able to survive solely on the crops produced by their vertical food gardens.

"Windowfarms let us do a lot with the little amount of space we have," says Riley. "You can grow up to eight plants of whatever variety you choose in a one column Classic system."

The Windowfarms system is modular in nature and can be adapted to fit most windows. It is also said to require minimal maintenance - with urban farmers only required to change the water once a week, give the system a monthly clean and keep an eye on the crop. As the pump is activated only a few times per day, the system doesn't need much power to operate - the developers say that a Windowfarms system in New York, for instance, has been found to cost about US$8 per year to run. For locations not blessed with ample natural light, LED lighting solutions are to be added to the Windowfarms website in the near future.

The new Windowfarms system is currently awaiting funds from the Kickstarter crowd-sourcing portal - at the time of writing, the project has already reached its funding target with ten days remaining.

A one column Classic Windowfarms kit would normally be priced at US$119.95, but the project has reduced this to US$99 for Kickstarter backers. The Classic kit includes four plant containers, four net cups, a metal frame, an air pump, plumbing tubes, a hanger and a stand (for the option of window placement or free standing systems), a timer, a reservoir and cover, and some clay pellets. Pledgers can also get a four column kit for US$269. Bottles of the organic, sea-derived nutrient solution and 3-4 inch (7.6 -10 cm) tall baby plants (seedlings) are also available.

A special Classic kit is available to international backers for US$169, which includes shipping costs, but doesn't include a pump or timer - buyers will instead need to source such things locally.

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