| When you
consider the problem of fitting a sprinkler timer to 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 a third. All 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.
The next limiting factor is to consider how much water
can be supplied to the landscape through the meter, measured in gallons
per minute. Sprinkler heads each are rated for the amount of water
that will be emitted at a given pressure. A typical 15 foot
radius full circle head uses 2 gallons per minute. In areas that are going
to be irrigated with spray heads I mark out on a plan how many heads will
fit around 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, the amount of water needed can be
calculated from the requirements of each head. Then the area can be
divided into zones so that each zone will have enough water supply to
support all of the heads.
Planning a sprinkler system from scratch is often easier than
fixing an existing one.
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
some of the people likely to use the timer are computer illiterate a
mechanical timer becomes more appropriate. If money is the key
aspect of planning, go for a home center special, they are often
frustrating to figure out but they work and they are cheap. A
battery timer is a choice of last resort, they rarely work for long but if
the cost of running power out to a valve is too extreme then this may be
the best answer available.
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 clock.
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.
Battery Timer:
Battery Powered single station timers can fulfill a need for awhile. I find
that they rarely last more than a single season. And sometimes not
even that. 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 them out there, none that I recommend
without some caution. Disconnecting the 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.
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 sequentially.
They must be mounted indoors. They cost in the $40 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 complete reprogramming them from scratch. They 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.
The Real Deal:
If the timer has 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, it will do what you need. I have recently
seen several models that have weather stations attached. Some are
even pretty reasonably priced. When they hit the stores, I will
update.
Product Review:
I have recently product tested a new irrigation timer that connects to my computer
via my home network. The Ware Brothers timer has worked flawlessly thus far. I use the
timer to control the X10 system of remote switches. So the same
timer runs my lighting system, my fountains, as well as my sprinkler system.
Photo cells are unnecessary as the timer calculates start or end times for
my lighting system based upon sunrise and sunset calculations or upon real
time depending upon your preference, though it does have room for multiple sensors such as wind
velocity, rain, soil humidity, pressure sensors in sprinkler lines.
This last feature will actually show if a leak in the sprinkler
system has developed due to the change in pressure and an error message
will show which valve has the problem. If the power goes off all programming
is saved in the flash memory. A watch battery maintains the clock time for as long
as 5 years. The programming is easily done on a html web page so there is
no issue with Apple or PC computers. Even more alluring to me
is that I can control timers on other projects as well from my home
computer via the web if the client has a DSL connection. The timer
has a separate IP address from the home computer so there is no invasion
of privacy. They run 16-32 valves with separate control for
each. When the irrigation system becomes complicated it is important
not to double up run times. The timer will run each valve
sequentially even if your programs overlap and a separate page shows a
chart, graphically depicting the watering schedule. Try to get your
irrigation timer to do that. The price is very attractive as well.
The home page for the Ware Brothers timer can be found
by clicking on the icon. A discount coupon can be redeemed by typing
in CALIFORNIA_GARDENS when prompted
while you are purchasing your timer. Contact
me if you would like more information.
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