An Automatic Drip System for my New Coldframe

Last fall I built a coldframe on the south side of the Ark, which I watered by hand all winter.  Last winter I installed an 1100-gallon rainwater catchment tank on the north side of the Ark.  This summer I connected the two.

Starting at the top of the system, this picture shows how I modified the rainwater inlet.  Originally the gutter pipe had a straight shot into the tank strainer.  I discovered that when it was raining heavily, the water coming out of the gutter had enough energy to shoot right on out of the strainer.  This is due to the drop of several feet between the gutter and the tank, which gives the water lots of energy, and the sideways angle of the pipe, which gives the water lots of lateral velocity.  I figured the answer was to install a right-angle bend at the end of the pipe, to force the water straight down into the tank.

Another improvement I plan to make this winter is to install an overflow pipe at the top of the tank, so I can pipe this excess water over to a nearby garden spot.  No sense wasting water whenever the tank is full.

I have two 3/4" pipes coming out of the tank.  The pipe on the left goes to the coldframe, and the pipe on the right can either fill a 5-gallon bucket, or be hooked to a garden hose.



The pipe to the coldframe is buried in a trench to prevent freezing, and goes under the Ark foundation.  The fence wire is temporary, to keep my firewood stash under the water tank platform from floating away in case of a flood.  (The river didn't flood this summer.)

This is the brains of the system, a low-pressure timer from Dripworks.  (Dripworks offers an informative free catalog.)  The water pipe runs along the ground inside the Ark.  In an attempt to avoid flooding the timer, I installed it 5 feet above ground level.  The valve is designed to bleed off air in case a bubble forms at the top of this awkward configuration, but it looks like I don't really need it.

A final piece of equipment -- an in-line filter which prevents clogging of the T-tape.  The pipe goes through wall into the coldframe.

  

Looking straight down onto the final control assembly.  Each outlet has its own valve, which is probably overkill, but the valves were very inexpensive.  The black T-tape is an inexpensive way to drip irrigate, and performs well with low pressure.

The T-tape runs the length of the coldframe, and will soon be covered by vegetation.  This is the high-flow T-tape, with emitters every 8".  I'm planning on using 5 gallons of water for each daily irrigation, so I'll set the timer to open its valve for about 30 minutes each day.  A tankful of water should last about 7 months.  By the time the tank runs out of water next spring, my outdoor garden should be in full production.  Then next summer's rains will (hopefully) fill the tank for the following winter's coldframe garden.