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What can an automatic controller do for your irrigation system?

It can save water or waste it. You need to choose the right unit and program it correctly

By turning your irrigation system on and off automatically, a controller can be the simplest and most efficient way to water your garden. However, it can also waste water. To work optimally, a unit has to be the right one for your garden, it must be properly installed, and you must program it carefully.

More models than ever are now on the market, offering greater flexibility in scheduling, more precise watering, and options that let you tailor the system to your plants' exact requirements. But no matter what type you buy or already have in place -it needs periodic reprogramming and maintenance.

Getting control

Hardware and discount stores sell a limited range of controllers. But, if you have more than just basic needs, your best bet is an irrigation supply store; its staff can help you choose a unit-- and show you how to run it.

Key considerations are the size of your garden, the design of your irrigation system, the kinds of plants you grow, and how many valves you'll be running (your controller generally needs one "station" for each valve).

Bear in mind the different water requirements of your plants-from multiple daily sprinklings for a newly seeded lawn to monthly deep-watering of certain trees or shrubs. Programmability should be sophisticated enough to suit your specific needs. A controller with a limited calendar (one whose maximum gap between waterings is four days, for example) can force you to water so frequently that many kinds of plants would suffer.

Simple solutions for small gardens

There's no point in spending a lot on a fancy controller if you'll use it for just a vegetable bed and lawn, if you have a small garden with only a few shrubs and trees, if occasional hand-watering can take care of most plants, or if you live in a mild climate and grow plants that need little supplemental water.

But even if the smallest unit suits your needs, one with at least two programs will prove handier. Such units are also quite affordable: ones with two programs, seven-day calendars, and four to six stations generally cost $55 to $150.

For a small area not handy to electricity, you can use a battery-operated unit. At $50 to $100, these cost as much as or more than some dual-program controllers; they are more fragile and should be stored indoors in winter if temperatures drop below freezing.

If feasible, a 110-volt electrical type is the best choice.

Sophisticated options for a range of watering needs

To water plants with more divergent needs, you'll need a multiple-program clock. Costs range from $200 for models with 4 programs and 6 stations to $400 for 12 programs and 12 stations. (Beyond 12 stations, controllers get prohibitively expensive for most home gardeners.)

Multiple programs are useful only if plants are grouped according to water needs, with a separate valve for each grouping. Ideally, for instance, you would use eight valves for a yard with separate zones including large containers, lawn, moisture-loving shrubs in shade, ornamental trees, flower beds in sun, small containers, sun-loving drought-tolerant shrubs, and a vegetable garden.

If your landscape isn't zoned, your current irrigation system could be hard to retrofit. This may be a good opportunity to redesign your landscape and install a new system-using drip for most of the garden and sprinklers on the lawn-that lets you automatically give plants just the amount of water they need.

Other features for flexibility

Buying a controller with at least one or two additional stations will let you add to the system later. Other useful features are 10-hour run times (good for drip irrigation), extended calendar periods (14 or 31 days), rechargeable battery backup to retain both the program and the time in a power failure"select-a-day" scheduling, and weatherproof casing for outdoor installation.

The basics of installation

Instruction manuals will lead you step by step through installation. But it helps to have an overall picture of what's involved. Controllers fall into two categories-indoor and outdoor. Indoor-mounted controllers are usually less sophisticated and have to be protected from the elements. The unit comes with a transformer that plugs into an existing three-prong outlet. The only wiring you have to do is lowvoltage, from the valves to the stations on the controller. (If you have manual valves, you'll need to either replace them with electric ones or install converters-"electric actuators"-if available for your models.)

Each valve has two short wires. One is live, the other is a ground wire. To each of these you connect a length of cable (available at hardware stores and from irrigation specialists). If it's going underground, it should be labeled as being approved for direct burial.

For most residential gardens, use 18-gauge jacket cable with multiple strands of wire (commonly available types have 6 or 10 strands)-one for each valve and one for a common ground wire (usually white). If your system has more stations than there are strands of wire, you'll need more than one cable.

In some cases, your irrigation supplier may suggest using single-strand cable. Since it has only one strand of wire, purchase an extra cable (usually white) for the ground wire.

Outdoor controllers are weatherprooc with the transformer contained in the unit. When used indoors, the unit can be simply wired to a plug; most irrigation supply stores can show you how. Outdoors, they must be 110-volt conduitwired; it's best to hire an electrician for the job.

Don't forget to waterproof the connections on outdoor valves (wherever you buy other irrigation supplies, ask for a product that will do this).

To program a controller, learn the lingo

Since every brand works differently, the first step to programming your controller is to learn its features and vocabulary (see glossary above). With a little initial coaching from the salesman and with a manual in hand, it should be fairly simple. Plug-in types can be set up indoors temporarily so you can experiment with them in a comfortable setting. Remember that a controller will be useful only if you tell it exactly what you want it to do.

Programming a controller involves making four primary settings: the time of day on the controller, which days you want to water (calendar), the time you want the watering cycle or repeat cycles to begin (start time), and how long you want to water plants on each valve or station (run time or station watering time).

When setting the start time, remember that valves on the same program will automatically turn on and off in sequence. You don't set a start time for each valve, just for each program or repeat cycle.

Not all controllers allow repeat cycles, but if yours does, you can set one program to turn on twice a day or more-in the afternoon, for instance, to help moss baskets that may need a second watering in hot weather.

One of the most common mistakes when scheduling the watering time is to run the system too frequently and for too short a time. Most established plants need infrequent, deep soakings. For instance, many established shrubs can get by on one deep watering every couple of weeks.

You may want to write down your completed program-a handy reference if all power is lost and you have to reprogram the controller.

If someone other than an irrigation specialist installs a controller for you, don't assume that he or she knows how to program it also. Don't assume that your gardener knows, either, without training that's specific to your brand.

If you have trouble operating the controller, call the store that sold it to you. In the instruction booklets, most manufacturers also list a telephone number you can call for help.

Don't ignore it once it's operating

It may be easy to assume that, once the controller is programmed, you never have to think about it again. But all it can do without effort on your part is turn your system on and off. To avoid wasting water, it must be adjusted to compensate for several factors, including plant growth and change of season.

Check soil moisture around roots periodically to make sure plants are getting enough water. They may need additional irrigation in bot, windy weather. A manual override feature allows you to start watering cycles manually without throwing the controller off schedule. Some clocks have a feature called water budgeting which allows you to make adjustments to run times. Use this feature to make seasonal changes in lawn watering. However, don't use it for trees and shrubs; for them, adjust the frequency, not the duration, of watering.

To make your irrigation system as responsive as possible to actual water needs, use an automatic rain shutoff or soil-moisture sensing devices to regulate the controller. (For more information about such devices, see page 270 of the May 1988 issue of Sunset.)

Don't forget to check periodically to make sure your controller hasn't lost its settings or malfunctioned in some way. With most controllers, whenever there is a power outage the clock will stop (most battery backups save schedules, but not the time of day on the controller). Replace nonrechargeable backup batteries regularly.

Making sense of controller jargon

When you set out to program your controller, you'll encounter some jargon that can seem forbidding. Here we define a few of the most common terms and phrases.

Station: the controller's electrical hookup that operates a valve (the device that opens and shuts to control the flow of water to each irrigation line). Wiring connects each station to a separate valve. Program: a schedule on which a station or group of stations operates.

Dual- or multiple-program: a controller's capability to run two or more different schedules.

Start time (cycle start, program watering time): the preset time at which a program activates the first station, beginning the watering cycle.

Calendar: day schedule on which the time is set to water (could be days of week or days between watering),

"Select-a-day": a special feature allowing schedules to be set at intervals of several days (every third day, for instance) instead of at specific days of the week (such as Tuesday and Friday).

Run time (duration, station watering time): minutes or hours each station is set towater.

Repeat cycle start (multiple cycles): a feature letting you set stations to come on more than once in a day.

Rain shutoff (rain override): turns off the controller without losing the program.
COPYRIGHT 1989 Sunset Publishing Corp.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Title Annotation:includes related article on controller jargon
Date:Jun 1, 1989
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