DURABILITY?
Rainbeds are mostly cedar, which is a highly durable wood for exterior use. The exterior surfaces are treated with a water-based wood stain to protect the wood from rain and sun. The original standard Rainbed is now three years old and looks like the day it was installed.
SUSTAINABILITY - MATERIALS?
The cedar used in Rainbeds is certified by the Forest Stewardship Council to be sustainably grown, harvested and processed.
SUSTAINABILITY – OPERATIONS?
Rainbeds do not require an external source of water. 14” of annual rainfall provides enough water to fill the tank for the growing season and grow vegetables from start to finish. Seattle and Portland get 37” annually, Austin Texas gets 34”, San Francisco get 22” and Los Angeles gets 15” of annual rainfall. The rain can come as sudden downpours or frequent showers. It all gets harvested.
THE MATH
1” of rainfall on 1 square foot of surface area equals 0.63 gallons of water. The area of the collectors on a standard Rainbed is 34.67 square feet. Each inch of rainfall harvests 21.8 gallons of water.
The surface area of the garden is 29.4 square feet. The rule of thumb for irrigating a garden is one inch of water per week per square foot of garden area. June 1st through September 30th is 17 weeks.
The garden needs 17 inches of water per square foot. That’s 315 gallons of water. The volume of water in the tank is 41.75 cubic feet. Each cubic foot contains 7.48 gallons. The capacity of the storage tank is 312 gallons of water.
It takes about 50 pounds of water to produce 1 pound of food. Water weighs 8.35 pounds per gallon. The 312 gallons weighs over 2,600 pounds, enough water to grow over 50 pounds of fresh produce.
WATER QUALITY
Rainwater is better for growing gardens than tap water because the pH of rainwater is between 5.5 and 6.5, which is idea for most vegetables. The pH of tap water is raised to 7.5 or higher to limit corrosion of water system pipes. That’s why gardens perk up noticeably when it rains. There are also other additives in tap water, including chlorine.
The tank liner is fabricated from a vinyl polyester fabric, which is both safe and durable.
The water tank is fully enclosed and no sunlight gets in. Copper in the plumbing system acts as a natural algaecide to further insure water quality. When we moved my three year old Rainbed to a new location, both the water and the liner were like new.
ACCESSIBILITY
The surface height of the garden bed is 32” above the ground. There are 8 standard Rainbeds in a parking lot at a senior living facility. The Rainbeds are five feet apart to provide wheelchair accessibility to residents. There is no bending over to tend a Rainbed garden.
USABILITY
With your fertile soil and your gardening skills, the Rainbed can provide about 50 pounds of fresh food every year for many years to come. The Rainbed does not require an external source of water to grow vegetables.
COST / VALUE
The oldest Rainbed on the planet is only 3 years old, and it is like new. The only moving part is the hand pump. I expect at least ten years of successful operation. The water harvested and used is free and the garden will be ready to provide fresh food for many years.
CLIMATE CHANGE
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