Irrigating the garden while away

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Irrigating the Garden While Away

I’m a national trucker. I am gone from home between 2 and 3 weeks most of the time and a maximum of 5 weeks sometimes. I talked a friend of mine that has a small garden spot into watering the garden this last summer by pumping water from the pond with a gasoline powered water pump. This was a 1.5 horse pump that pumped 1,800 gph(gallons per hour) through a 1″ line. This wasn’t a bad way to go and didn’t use much gas. I bet we didn’t use 2 gallons of gas all summer. We were only running it for 30 minutes every 2 days or so and there were several wet weeks when we didn’t water at all. However I am burdening my friend with this chore. I had been looking for a more automated system and I still am. So in this article I will explain what I’ve come up with so far.
This pump with pipe and fittings solution has cost me $300 so far. I priced a solar pumping system at between $600 and $1,000 and that doesn’t count pressure tanks, irrigation lines and drip emitters. I’ll list some websites of interest below.
Irrigating the Garden 2013
Grow Your Grub Podcast
Dripworks
Cycle Stop
Irrigation Direct
I got the third link Dripworks from the Grow Your Grub Podcast. Dripworks has some nice looking drip emitters that work from 10 psi up to 50 psi. Some of them are also are self flushing and easy to take apart and clean. Cycle Stop has a valve that keeps the line pressure more constant. I’m not sure that will be important but I thought I’d mention it. Irrigation Direct has pressure regulators, as well as Dripworks. One I was looking at keeps a line at 20 psi, screws onto a hose and didn’t cost much.

$25 pressure switch, $150 to $600 for pressure tank, $100 to $200 for a decent pump. We could pump directly from the pond into the pressure tank or we could pump from the pond into some settling tanks ($45 each) and from settling tanks into the pressure tank. We have pumped pond water into 50 gallon drums and stock tank and it clears up as clear as spring water with a small amount of time settling. We could run power to the garden to a pump house or we could put the pump house near the house and pond dam and run pipe to the garden. To run outdoor underground wiring 300 feet $700. To run 1″ black pipe 300′, $60 to $90. I think I’d rather run the pipe, even though it would be nice to have power at the garden spot.
We need some way to shut off the watering during rainy periods. I have found a few options. One is called “Smart Irrigation Controllers”. These use soil humidity probes. The probe use electrical conductivity of the soil to determine moisture content. They need to be buried in the root zone or about 6″ deep for garden veggies. They have to be calibrated to your soil. On a couple of dry days you would water over the probe and soak the ground. Then wait 24 hour without any rain or watering and set the calibration. There are also guidelines as to where to place the probes in relation to plants.

They make basically two types. One type shuts your sprinkler timer system off based on high moisture. The other starts and stops the sprinkler system based on moisture. I have yet to find one in a price range that I can afford, meaning much less than $1,000. And some I find want to give you a quote which is always a bad sign. I can’t believe this technology costs so much. The probes are cheap, so it’s the controller that is expensive and I see no reason it should be.

Another option for us is to use a sprinkler timer with a remote control so that my friend can simply watch the weather and turn it off in rainy periods from his house 300 feet from the garden. These are not expensive and it’s a simple solution, so it is probably the one we will go with. Finally there are rain sensors which can be plugged into the sprinkler system. But I fear they may be prone to failure and would have to be monitored to make sure they are functioning properly.
For drip irrigation we have this 1/4″ (100′ $6) black tubing. Some emitters can be used with 1/8″ (100′ $4.50) tubing as well. We also have what is called drip emitters and what seems to be quite a few different types. There is also drip line and drip tape. I’m not sure we will need it. I might get some and try it out. Some emitters are called non pressure compensating and around near 20 cents each. This means they do not alter the pressure and work between 15 and 20 psi. This gives different GPH rate based on the pressure. However if your pressure is lower they will still work only at slower GPH rates. So if you want to try gravity flow from a tank near ground level, you must use these non pressure compensating drip emitters.
That brings up a point. Another alternative to the pressure tank setup would be to elevate the tank 21′ vertically above the garden. We get .433 psi for every foot of elevation. This would give 10 to 15 psi required by the pressure compensating drip emitters. The only way we could do this is to put the tank on a hill, as it would cost too much to build a water tower. In our case, the hill is 300 or 400 feet away from the garden. This is not altogether out of the question since black pipe is so cheap. And I think our gasoline powered pump would pump water up to the tanks just fine. I’m just not sure that I want to go to that trouble. I think using a pressure tank, pump and switch will be our best option.
The other type of emitter is the pressure compensating drip emitters at just under 40 cents each. These have some diaphragm in them maybe similar to micro pressure tank. They kind of look like a micro tank. These work in the 10 to 50 psi range. A water pressure regulator may still be a good idea as most household pressures can be 60 to 80 or so. What I assume this type does is to keep the pressure constant to say 10 psi so that a constant flow rate is achieved. These can be 1/4, 1/2, 1 and 1.5 GPH.
So far this last summer we prepared about 50 square feet of garden space. If I want to place a drip emitter in each square foot I will need hose and 50 emitters. I will also possibly need some couplers and T’s etc. 100 ft of 1/4″ line might do it for us. I intend this winter to expand the garden to 100 square feet SFG space and develop the sunny pond side with some 20′ rows. The row area will be approx. 20′x16′ and might be a good place to try out drip line or drip tape ($12 for 100′ or $100 for 1,000′) We would need to spend about $25 for drip tape as a minimum.
There was one interesting looking controller that comes with a phone app. And there was another that let you control your watering via a website. So the technology is coming along well, it just needs more development and more production and sales to bring the cost down. So in conclusion it looks like it may cost us something around $1,100 to implement this plan for next year’s gardening. And one alternate method I didn’t mention was to use some kind of filter and pump water directly from the pond into the pressure tank.