The Pinnacles Greenhouse Irrigation System
December 2, 2012 § Leave a comment
By Kyle Brookens
The irrigation system in the Pinnacles Greenhouse has a relatively simple design. The permanent beds are irrigated with 1/2” drip tape, the holes in the cinder-blocks are irrigated with .5gal/hr drip emitters, the tables are irrigated with seven small adjustable sprinklers that spray 180 degrees, the hanging pots are irrigated with .5 – 1gal/hr drip emitters, and the trees are irrigated with a 1/4” drip ring. There is potential to incorporate the shelves in the left corner of the greenhouse because a plugged 1/2” black polyethylene supply tube is tied into the 1” PVC underground supply. For each zone (permanent beds = 1, table = 2, hanging pots = 3, and trees = 4) a 1/2” valve was installed on the supply line to control the flow of the incoming water. This was installed because the drip emitters do not require as much pressure as the small sprinklers.
Starting from the hose bib, we installed a 4-way split. Currently, only two of the splits seem necessary, but the other two may come in handy in the future. One occupied connection goes to the garden hose for hand watering. The other occupied connection supplies the entire irrigation system. The water must be turned on at all times for the system to work properly. A short 5/8 hose connects to the timer which has four different program times. As of right now, we are only utilizing two of those (one 2 min run-time in the morning and one 2 min run-time in the evening). In the summer it might be convenient to have the other two programs run during the day for a short time to increase humidity and lower the air temperature. From the timer, a 5/8 hose connects to the basic 155 mesh Y filter. The 125 psi pressure gauge comes next, then the 22 psi pressure reducer, and followed by the 30 psi pressure gauge. A bib and adapter connects the 5/8 potable water hose to the hose bib assembly. The hose then connects underground at a depth of 5-6 inches to the 1” PVC supply line. The supply line has 3 T’s and 8 elbows that distribute the water to the 4 working zones and 1 expandable zone in the left corner. In areas where the pipe will experience heavy foot traffic, we housed the 1” PVC in 1 1/2” steal pipe to prevent damage occurring to the underground pipes. At each zone the 1” PVC converts to the 1/2” polyethylene black pipe, usually underground. Each PVC connection was primed and glued and each 1/2” tube connection was taped and/or secured with a hose clamp.
The irrigation system is about as simple as we could possibly make it. We utilized materials that we obtained for free and made the system very easy to understand. There is a downfall to the simplicity of the system: the timer runs off of a rechargeable 9 volt battery. We purchased a back-up 9-volt battery and the appropriate charger. The best way to ensure that the timer never fails is to swap the battery with a freshly charged battery before a long holiday (such as Thanksgiving, Christmas, and spring break), and to swap the battery before it runs completely dry. Other than this small obstacle, the system is completely automated, and therefore, it allows the greenhouse operator to spend more time tending to the plants, soil, and aquaponics system. The attached jpg file is a useful diagram of the entire irrigation system as of 11/27/12.