As opposed to regular irrigation systems, the HDPE or PVC lines of which should be blown empty of water before the frost comes, The Plant Booster system does not need the same treatment.  Other than disconnecting the Faucet connector cap from the garden faucet, there is no need to winterize the system.  The 1/16th" ID polyurethane tubing simply expands with any frozen water in it, and that does not cause damage to the tubing.  You might like to spray some WD40 lubricant on it to protect the galvanized bolt and wingnut from rust.  The springs and hinge pin are stainless steel and will not weather.