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Irrigation Timer

How much sprinkler timer do you need? Is a smart irrigation timer worth the cost or effort?

I have my favorite sprinkler timers.  And those that make me nuts each time I try to program them.  I have sprinkler timers that are a visual blight to a garden and others that are in the crawl space under the house, neither is even remotely enjoyable.  Finding a spot to put your irrigation timer that is both convenient to electricity and to the valves is critical.  I like to have the irrigation timer in the shade.  Hot reflective sun can damage electronics and destroy plastic housings and unnecessarily stress out the gardener.  I like to have the irrigation timer high enough off the ground that I don't have to crouch down to see the readout.   Putting a sprinkler timer in a spot that is usually locked up or in an area that can't get dirty defies logic.  The worst situation that I encountered was  where the valves and timer were all packaged against the side of the house in a wooden cabinet with no door.  I had to disassemble the cabinet to work on the sprinkler timer.  And worse yet they used cheap valves that kept breaking, each time making a mess of the irrigation timer as well as getting water in the structure.    After several episodes I finally convinced the owner to improve the system.  Sprinkler repair inevitably involves mud and multiple treks to between the irrigation  timer and valves to test to see if everything is working properly.   Hard to access equipment makes everything that much more difficult.

When you consider the problem of choosing a sprinkler timer for a landscape you first look to divide the landscape into comparable zones.  Sunny lawn areas all grouped together, drought tolerant shrubs in another zone, shaded areas or pots in the next.  Each of these sections of the irrigated landscape will have different needs of irrigation frequency as well as the length of time the sprinkler timer will be set for each section or zone.   Each type of landscape will require a separate program on the timer.  Most sprinkler timers come with 2-4 programs.

The biggest limiting factor is to consider how much water can be supplied to the landscape through the meter, measured in gallons per minute.  Sprinkler heads also rated in terms of gallons per minute at a given pressure.In areas that are going to be irrigated with spray heads I mark out on a plan how many heads will fit around the perimeter of the space to be irrigated.  This can be done on the ground if the landscape is already in place.  The heads should be spaced so that one sprays onto the next and that all heads in each area are of the same type.  If heads of different types are mixed the rate of precipitation will not be consistent, leaving you with wet and dry spots.  Once the sprinkler heads have been located I mark on the plan the amount that each sprinkler head emits under ideal conditions.  I then divide the area into equal parts each requiring significantly less water than the meter can provide.

Planning a sprinkler system from scratch is often easier than fixing an existing one.

When I choose the sprinkler timer I start by calculating how many stations, or valves will be in a system.  Then I look to see who will be using the timer.  If it is the gardeners and they are comfortable with timers, using a good quality timer will save time and money in the end. If you want to consider a computer controlled timer but If some of the people likely to use the timer are computer illiterate or if the electricity is not dependable a mechanical timer becomes more appropriate.  I find these sprinkler timers frustrating to figure out but they work, and they are cheap.  Each one seems to have a different programming logic.  So I often have to read the manual repeatedly to finally figure each one out.  A battery powered sprinkler timer is a choice of last resort, they rarely work for long and are fragile if the pressure is high, but if the cost of running power out to a valve is too extreme then this may be the best answer available.  Recently it has become common for water companies to provide partial rebates for water saving smart timers.

Battery Timer:
Mechanical Timer:
Home Center Special:
A Decent Timer:
Essentials Only:
The Real Deal:
Product Review:

Typical Program: I water lawns two to three times a week, sometimes with a double cycle on the days that they run in order to get better penetration.  I run potted plants as often as once a day.  Many shrubs and fruit trees perform best on a weekly watering or even less frequently.  A new lawn will be watered three times daily.  With each of these different conditions I need another program for the sprinkler timer.

Design Criteria: I design sprinkler systems so that they do not lose pressure if someone flushes a toilet. I look at the meter size and check the pressure. I cross reference those two pieces of information. And figure out the gallons per minute that the meter can supply. I then check to see that the pipes are working reasonably by running a hose at full force to see that the pipes are not blocked by rust. An old pipe may only have a space the size of a pencil for the water to pass through. I use no more that 75% of the water that I estimate is available. Each head is rated to emit a certain amount of water. I add up the ratings for each head that I use on a system until I reach that 75% of the available water. Once I have enough heads on a valve to use up all of that water I put in a new valve. I try to keep all of the sprinklers on a valve watering similar types of plants: i.e. lawns, shrubs, groundcover, vegetable garden . . . etc. That way I won't have to keep that fuchsia happy when the rest of the more drought tolerant plants don't need it. I like using a timer because I often get distracted and forget to turn off the water in a timely manner. I also like to run the water at night when the evaporation of that water will be at the lowest rate possible.

How much Power? The more complicated problem is to decide how many features are necessary.  Sometimes the answer is none, because it is just too much of a headache.  With the Nelson Traveling Sprinkler you set the hose to the path that you want the sprinkler to follow and turn it on.  And a hose caddy that works.

Battery Timer: Battery Powered single station sprinkler timers can fulfill a need for awhile. I find that they rarely last more than a single season. And sometimes not even that.  Every one that I have put in eventually came to a bad end.  The weather is hard on them. The minerals in the water harder. The pressure of the waterline is the final killer.  There are lots of single station sprinkler timers out there, none that I recommend without some caution.  Disconnecting these irrigation timers during the rainy season is essential.  Ensuring that the pressure is not over 60 psi is critical.  I think that the best way to use them is like a kitchen timer where you turn the water on and it turns the water off.  Then you go back out once you remember and turn the water off to the timer.  This is certainly cheaper than to risk allowing the water bill to mount unchecked when the valve finally breaks.

Mechanical Timer: The simple mechanical sprinkler timers usually run up to an hour on each station. They are set by rotating a number of geared wheels and will always do what they are told to do so long as the electricity is on. They are being replaced in the marketplace with the inexpensive electric timers and cost in the $60 to $150 range.  But their reliability if nobody is going to be around is unsurpassed.  They just start back up where they left off once the power comes back on. 

Home Center Special: The cheapest irrigation timers are about the size of a TV remote controller. They run electrically. All of the information is on a small LED screen. Each of the programming elements must be programmed in sequence. These irrigation timers must be mounted indoors. They cost in the $20 to $60 range. It is often difficult to program them or find out how they had been programmed so the program can be manipulated without completely reprogramming them from scratch. If the power ever goes off they quickly forget their programming once the battery runs out and most resort to 10 minutes per day on each station every day once the power returns to save your plants until you figure it out.  The timer below is a cut above the others.

A Decent Timer: With more money outdoor housings come on the irrigation timers, and extra buttons providing more direct access to the different parts of the programs. I like to have the timer outside. Usually when I am fixing something on a sprinkler system I am a muddy mess and I don’t want to track all of that in and out of someone's house or garage while checking my repairs. By the time you get into the $150 to $200 range most of the programming features have been provided: multiple programs, multiple start times per station, global changes to watering times and frequency but they still fall back to the default program when the battery runs out. Sometimes this is a very short time, check the spec sheet.. With some irrigation timers a power outage of as little as 45 minutes is enough to drain the 9 volt battery and to lose the program even on a new battery. The next jump in timer quality runs the cost to $350 to $700. For these timers the program memory does not get lost. The battery just retains the time. The keyboard can access all parts of the program and will list out prior programming with just a few keystrokes. Others on this price level have remote control which is great for testing valves while you are out in the landscape. The top level of timers can be manipulated from a computer through a telephone line.  Most can be operated remotely throughout a project. Great to test the valves while 100 yards or more from the timer and often at the bottom of a hill. I think this sounds pretty darn convenient, speaking as one who frequently has to drive to check, manipulate, and repair timers. This is probably not practical for the average tract house but these remote features can be a great help for larger landscapes and horse properties.  For more money there are more stations and more sensors.  Wind and rain are good.  Moisture sensors are still a little sketchy in my opinion, but getting better.

Essentials only Generally I use two of the timer's programs. The first is for the lawn areas and the second for the trees and shrubs in the  beds, the times for the different zones may vary due to amount of sunlight and types of heads but the frequency is the same. The second program covers the beds of drought tolerant plants. I use the third program for newly planted areas but almost never have a call for more than 3 programs. I often use two cycle starts for syringing beds. On newly seeded lawns I often use 3 cycle starts for the first couple of weeks.  I put that onto that third program.  Or if I have a bunch of potted plants they often get put on that 3rd or 4th program.

The Real Deal: More and more the best sprinkler timer is becoming a smart timer.  The smart timers have some way to vary the amount of irrigation time relative to the weather automatically.  Some have onsite weather sensors.  Others call the internet and check a local weather station for information.   Some smart timer manufacturers provide information for the timer as a monthly subscription.    Some smart timers even can be called through the internet from a remote location and have their program manipulated.   This can make your I-phone the best universal remote control device in the world.  If the timer has at least 3 programs, 3 cycle starts, can run as long as it takes to make water run-off on the longest cycle, and as many stations as there are sprinkler zones, in most cases it will do what you need.

Product Review: I have recently product tested a new smart  irrigation timer from Cyber-Rain that connects to my PC via a wireless connection point.  The Cyber Rain timer is easy to program.  The program is pretty flexible.  You program the smart timer for the worst that the weather can send your way and the smart timer adjusts for actual weather.  If the computer connection is down the smart timer is indexed by zip code for 100 years of historical weather data and matches the station times and the season.   The best aspect is that this smart timer connects to the internet and checks the local weather.  There is no subscription fee for this service unlike with some other arrangements.  Based on the heat index and evaporation rate the timer adjusts the amount of time for each station. After some progress this timer is still not Apple friendly.

smart sprinkler timer  

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Last modified: April 20, 2013