As I write this, we are looking forward to a weekend of lovely fall
weather in the 70s, followed by rain on the valley floor and snow in
the mountains. Last week I said it wasn't time to stop watering plants,
but it is close.
A colleague asked me today how to winterize the drip system at a school garden she has been working on, a timely fall topic.
Drip
systems usually lie above ground and freeze more readily than in-ground
systems. Although drip systems are more forgiving than in-ground
systems when it comes to freezing, it is important to protect a
system's timers, filters, fittings, backflow device and electric valves.
To
winterize a drip system, start by turning off the water supply to the
system. Uncrimp the end caps of the polytubing and completely drain all
parts of water. This will prevent lines from splitting or being
damaged. A good way to drain lines is to blow the water out with
compressed air at no more than 30 PSI. If you don't have an air
compressor, raise one end of the polytube above the other and let
gravity do the work for you. After draining is complete, cap the ends
of the tubes off to prevent critters, debris and dirt from getting into
them.
Bring the timers, backflow devices, filter regulator
assemblies and so on into the house or garage and store them in a place
they can't freeze. Remove any batteries from the timers to prevent
corrosion.
To help in the draining process throughout the
year, there are flush valves that can be installed at the end of a
polytube line or at a low point in the middle. These valves
automatically open up when the water pressure inside the tube drops
below a certain pressure. A self-draining line reduces potential freeze
damage, especially in those early and late freezes.
After
everything has been drained, it is OK to leave the tubing and the
emitters outside during the winter. With our winter sun, it doesn't
hurt to cover the lines up with mulch, but it is not necessary. If you
cover the lines, mark their location, so that when you start digging in
the spring you don't damage them with a shovel.
Check out all
the hook-up parts, timers, filters and valves and replace any O-rings
or washers in preparation for next spring. With a little maintenance, a
drip system can last for years.