Wednesday, June 1, 2016

Rooftop Gardening Without Irrigation Using New Technology

Rooftop gardening is receiving more and more attention as a potential solution to the serious problems caused by importing food into large cities.  As cities have expanded both horizontally and vertically, they have gotten ever farther from the farms that once surrounded them.  This has meant ever longer transport distances and costs (both monetary and environmental) to get fresh fruits and vegetables to city dwellers.  As more and more people live in cities it becomes ever more important to solve this problem.

Two problems have prevented rooftop gardening from becoming more common.  First, many roofs need structural reinforcement before soil and many people can regularly grace their surface.

However, even when this is completed, the challenge of watering rooftop gardens still exists.  This challenge is especially acute if the rooftop is composed of many small plots rather than a single large field.  While single large fields on a rooftop make constant drip irrigation (sometimes) worthwhile, this is not the case with a 4x4 or 4x8 foot plot.  If you have to take an elevator or stairs up to the roof - you are unlikely to go up daily to water a garden.

That is why the Groasis Waterboxx is such an fortunate invention. The Waterboxx works by collecting and storing rain and dew, and slowly releasing it to the roots of a growing plant.  The roots are planted directly in normal soil - the Waterboxx just sits on the soil.  In many cases,  the Waterboxx either doesn't need to be filled after set up at all, in areas with moderate rainfall. In areas with little to no rainfall, the Waterboxx only needs refilling with water every few weeks.

A schematic cutaway view of the Groasis Waterboxx:  Water is stored collected by the tan lid, funneled by the siphons shown in red into a 15 liter reservoir, and then slowly released via a woven wick.  Soil evaporation is also blocked by the Waterboxx - image from

How can you adapt a square foot garden or raised bed garden already on a roof to growing with the Waterboxx?  First, remove the lattice structure that separates the square foot garden into square feet.  Next, place an assembled but empty Waterboxx onto your unplanted soil and press down - this will leave an indentation with the central soil elevated above the rest in a figure "8" configuration.  This raised soil - in the figure 8 or barbell raised portion - is where you plant your garden plants.

Plant in the two ends of the figure 8 left after pressing the Waterboxx into the soil - this will be the area in the center of the Waterboxx.  

You want to plant once garden plants are about 8 to 10 inches in height.  One Waterboxx can accommodate two of many plants (peppers, tomatoes, eggplants, zucchini) but one of many larger plants like squash or watermelon is recommended.

Two eggplants - which will now have a Waterboxx placed around them to water and protect them
Carefully place the assembled Waterboxx around your plants and fill the Waterboxx with about 4 gallons of pure water - don't add liquid fertilizer as this can clog the Waterboxx wick.  The Waterboxx collects condensation every morning it is present and will completely refill with four inches of rain.  If you don't get much rain, check the water level in the Waterboxx once weekly - add water if needed.

At the end of the growing season, you remove the Waterboxx, remove the wick and store the Waterboxxes (they stack for convenient storage). In the spring add another wick and start again - the Waterboxx is designed to last for 10 years.

The Waterboxx can allow veggies to be grown on rooftops even in areas where there are few fruits and vegetables currently - so called healthy "food deserts".

You can buy the Waterboxx here.

If you would like to learn how to grow plants without watering with the Waterboxx, the best resource is the book The Waterboxx Gardener: How to Mimic Nature, Stop Watering, and Start Enjoying Your Garden available here on 

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