I have big plans for my garden this year. Big plans that involve ruby red tomatoes, fragrant basil, sweet peas and, I might add, a very cool irrigation system. I realized (with the gentle suggestion of my husband) that I may have overextended myself this summer. A new large garden, a berry box across town, a full-time job, a cottage food business and a crazy volunteer schedule has left me with very little time to run about tending to all of these interests. Unfortunately, plants don’t care. They want their water and will punish you by curling into sad ghosts of their former selves if left unattended. I knew I couldn’t make it to both gardens every day, so we needed a new idea. Our first idea was to install water barrels and use gravity to get the work done but at our new community garden, we have a few unique design requirements that required us to get more creative.
Our new garden is part of a school. Since there are little kids running around, it means no tall structures that they can hide behind or that could fall on them if pushed, so all the additions to our garden need to be knee-height or less. This poses some challenges when trying to use the traditional gravity-fed water barrel system so we worked some engineering magic on the irrigation issue.
What we came up with is a solar-powered water displacement system. We have a 35 gallon water barrel that we will fill most of the way and sink below the ground surface in the center of the garden. We have a solar-powered air pump that we use to pump air into the sealed water barrel to pressurize the atmosphere within the barrel. As the air pressure increases within the barrel it pushes down on the water within and water is forced to leave through an irrigation tube that runs out of the barrel. Water pushed out of the barrel is distributed via a drip irrigation system across the garden like octopus arms.
We calculated the flow rate out of the barrel to be 1.9 gallons an hour while the pump was functioning in full sun.
Supposing that the pump only functions at half that capacity during a given 12 hour period, that means our pump system will pump out 11.4 gallons per twelve hours, or for our purposes, per day. This is great news! With this system that means I can go about three days without stopping by the garden to water. We will be having our next garden work day this Saturday, and hopefully after that day we can set up the system and get to irrigating!
P.S. Our pump system received extreme supervision by Mooshu (the Science Cat) during its test in our bathtub…