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Moisture Sensors Make Sense

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It’s making headlines every day: “Drought conditions turn green lawns brown.” “Crop failures expected.” Some 66 percent of the U.S. is experiencing extreme drought conditions. While landscape companies may not be paying the water bill, their businesses may be. For instance, it was reported earlier this summer that landscape companies in the Midwest were seeing business drop by 20 percent overall. It’s a simple equation: when there’s no grass, there’s no grass to cut.

It may be hard to remember now that we’ve been in a recessionary spiral for the last few years, but bust was preceded by boom. Think about all of the new construction and the accompanying plantings that were done over those years. The housing tracts, office parks and condo developments that were built during the boom years are now in danger of losing their investment—billions of dollars in established vegetation.

And just when money gets tight, the rain stops falling. Homeowners and corporate site owners alike have less money to spend on green infrastructure. At the same time, water costs have skyrocketed. Recession combined with drought—not a pretty picture.

So how do landscape companies cope with this new economy of scarcity? One answer is by becoming more knowledgeable about water conservation. Knowing how to help cut clients’ water bills and conserve water will give you an edge over competitors who may not be so savvy. A vital part of that is in understanding how to use the latest technology when installing or retrofitting an irrigation system.

So how do you ensure that your client’s plant material has the proper amount of water, without wasting it? This is where the technology of sensing devices comes in.

Most of the major manufacturers of irrigation components offer rain- and moisture-sensing devices. Although the technology used may be different, essentially they all do the same thing: detect how much moisture is actually in the soil, or in the event of rain, how much rain fell. It will then tell the controller to water or not to water. Instead of a traditional timer that waters whenever the clock tells it to, even during a rainstorm, moisture and rain sensors water only when needed.

Rain sensors are installed on roofs and work in a variety of ways. All of them collect rain until a certain threshold is reached, then they send an electronic signal to the controller to shut off. Some rain sensors use a hydroscopic disc that swells with rain and shrinks as it dries out, turning the controller on and off accordingly.

“There’s a perception in the industry that rain sensors don’t work,” said Jeff Kremicki, product marketing manager for Hunter Industries, San Marcos, California. “What happens is, a rain event occurs, but not long enough to hit the setting it was programmed for. The property owner looks out, sees that it’s raining, but the sprinklers are still on. He calls the contractor and says, ‘This thing isn’t working.’” To offset that problem, Hunter makes a rain sensor with a ‘quick response’ function that shuts the system off immediately, as soon as it starts raining. “Rain sensors have been around for a long time, and performance has improved considerably,” adds Kremicki.

However, what is important is that once these devices are installed, overall water savings can be substantial.

Some models of moisture sensors can also detect soil temperature, conductivity and salt content. Many of them have wireless capability and can be remotely controlled by laptop, iPad or Smartphone. Some will work with any brand of controller.

Controllers are easy to understand—moisture sensors are a bit more complicated. “Many landscape contractors are very closed minded,” says Jon Peters, executive director of sales, Baseline, Inc., Boise, Idaho. “However, we’ve found that younger contractors are generally eager to learn about new technology.” Companies that make moisture sensors find that they have to do a better job of educating contractors, especially the technophobic ones.

One of that younger generation of contractors is Matthew Johnson, owner of Energy Construction, LLC, in drought-stricken Holt, Missouri. In business since 2004, he’s had success using moisture sensors. He loves the remote access capability. “If we have a line break, I can log in and shut the zone down,” says Johnson. “This technology is a dream come true. You don’t have to monitor as much. And if I do have to monitor, I can use my laptop. I can tailor my watering to the exact threshold capacity of the soil. With the software, you can fine-tune those settings so you’re not wasting any water. “ Why is saving water important to him? Johnson said, “I take my customers’ problems very personally.

We service a lot of churches. Their revenue comes out of the collection plate. I save them money, and they send us more and more work every year.” Johnson added, “If you have a client with 30 or 40 locations and you can save them a couple of hundred dollars a year on each site, that’s a great selling point.”

What type of system you go with will depend on whether it’s a new installation or a retrofit. Sensors that are hard-wired and buried in the ground are easier to put in place in a new development. The way these devices accomplish their job of sensing may also affect your choice of system.

“There are two camps in this industry,” said Larry Sarver, president of Tucor, Inc., Wexford, Pennsylvania. “One is ET (evapotransporation) watering, and the other is soil- and moisture-based. We combine the two methods. If you’re watering 100 percent ET, you’re overwatering. Combining ET with moisture and soil-sensing capability gives a more precise picture of the condition of your soil.”

Some systems that work well with retrofitting are completely wireless. These sensors ‘talk’ to the controller via high-frequency radio from up to 500 feet away. No digging or retrenching is required.

This is what persuaded Gordon Moss, owner of Oasis Irrigation, LLC, Eugene, Oregon, to try a totally wireless system. “I’ve been in business 28 years, and it takes a lot to get me excited,” said Moss. “But I think this is the cat’s meow.”

He has put sensors in for all his residential landscape clients, two restaurant chains, and at his own residence. “Our weather here in Eugene is crazy,” said Moss. “One day it’s sunny, the next day it’s pouring. This has cut down on a lot of overwatering.”

Moss has seen a lot of moisture and rain sensors come and go, but he rejected them all because of the need to run hundreds of feet of wires back to the controller and bury them. The wireless configuration of the Toro PSS (Precision Soil Sensor) system is what persuaded him to try it.

Most companies, however, save the wireless technology for the remote controllers. Going completely wireless may be easier at first, but there is a downside. “Anytime you have radio, no matter how good it may be, it’s influenced by a lot of things,” said Tom Penning, president of Irrometer, Riverside, California.

“You put a transmitter in a new development, the trees have ten feet of space between them, and you’ve got perfect line-of-sight. No problem. Come back ten years later, the trees have gotten bigger, and the branches are hanging over that transmitter. Someone’s built a playground. Now you’ve got a ton of interference in the way,” said Penning.

Aaron Monji, design consultant for Monji Landscape Companies, Bakersfield, California, uses moisture sensors for their “living wall” installations. “We were looking for something that would dramatically reduce the amount of water we have to use. We thought we could do that with an effective moisture sensor.”

And the results? “We have a 1,500square-foot intensely planted test wall at our studio that we were dramatically overwatering. The company rep told us to turn the water off completely until the sensors’ readings told us it needed it. This wall had no water for two weeks in the intense heat of Bakersfield (where temperatures regularly are in the 100s), and we didn’t lose a single plant. As soon as we cut the water back, we saw the blooms flush and the growth we had been looking for.”

Monji Landscapes’ success with moisture sensors has helped them with sales. “Clients are always hesitant about doing living walls because of the need for so much on-site maintenance,” said Monji. “The moisture sensors help us take boots off the ground and still guarantee against plant failure. We’ve found we can cut our active lines in half.”

Past bad experiences

But are these moisture-sensing devices really worth the trouble? Many contractors have negative memories about the earlier generation of moisture sensing equipment that didn’t work so well. The materials, made from what was available at the time, corroded quickly in the ground.

“Some of the old sensor companies that have come and gone have given the technology a black eye,” said Penning. “Somebody had a bad experience with a certain brand of moisture sensor and decided that all of them are no good. We have to fight against the stereotypes of all the companies that failed,” he said.

But current models are made of tougher stuff—newer materials designed to stand up to the elements, whether it’s soil acidity, tractor vibration or lightning strikes. Corrosion-resistant stainless steel, ABS plastic, resin, fiberglass, electronic components encased in epoxy— these new materials and combinations of materials are designed to address the shortcomings of the old models.

How they work

All the companies that make rain and moisture sensors claim to save time by requiring less time on the actual site. Wireless remote capability allows a groundskeeper to take readings or change settings using a laptop, iPad or Smartphone from wherever he is. Broken sprinkler? Simply log in and shut down the zone, then come back and fix it later.

Irrometer’s sensors are tensionometers, water-filled instruments that exchange water with the soil. They detect how tightly the soil is hanging on to the water by measuring its electrical resistance; the drier the soil, the higher the resistance. These units require a bit more maintenance, as they must be freeze-protected.

Some sensors use stainless steel rods that form an electromagnetic waveguide. How long it takes the wave signal to get from one side of the probe to the other tells the central controller how much water is in the soil, as well as its temperature, salt content and conductivity.

You could even ignore the calendar to a degree. “You don’t have to go back and reset your controller seasonally,” said Sarver. “You could keep it on the summer schedule and the sensor will keep overriding. Just pick the moisture level you want for each zone, and adjust accordingly.”

The process isn’t completely automatic, however. Most units will need some calibration following installation to set the sensitivity thresholds.

“If someone doesn’t do the calibration right, the sensor learns the wrong thing and doesn’t know what it’s doing,” said Penning. And there are some problems that mere technology can’t fix. “We don’t actually recommend that you control your irrigation entirely with moisture sensors,” said Sarver.

Virtually all of the new generation of moisture sensors can be remote-controlled. This means that a landscaper can be at one job and be able to read what’s going on at a different location miles away—and react to it.

Tucor’s units send data to a webpage. If the webpage is green, that means things are just right. If it’s yellow, it’s getting dry; green or blue, too wet. Condition red results in an email to the contractor that the plants are reaching a stress point—or worse, a permanent wilt condition. All of these settings are user-definable. You can then turn on the sprinklers or turn them off—all from your iPhone.

Even if business has dried up somewhat with regard to new installations, there’s still a lot of potential revenue out there just waiting for the smart contractor to scoop up. Remember that the owner of a site where you previously did a new installation now has an acute need to save water. “The first year of construction, the landscape company is more worried about the plants surviving,” said Sarver. “After the contractor is gone, the owner—who pays the water bill—will want to scale it back.” His need to save water gives you the opportunity to go back to that site and sell him a moisture-sensing system that works with the existing controllers.

Jeff Miller agrees. “Our industry is perceived as one of the biggest users—and wasters—of water out there,” said Miller. Turning that image around could be a selling tool. “Contractors should position themselves as water conservation specialists, promising their clients a return on investment in the form of lowered water costs.”

Companies that make moisture and rain-sensing equipment are finding that lack of rain has been making profits for contractors who have installed these devices. “In this current market space, retrofitting is the most important revenue driver,” said Sarver. “It’s big business right now.”

Jeff Miller, marketing manager for the U.S. and Canada at Toro Irrigation Business, Riverside, California, agrees. “Since new construction has slowed, we’ve targeted the retrofit market.” With retrofitting in mind, most companies make rain and moisture-sensing equipment that will work with any controller.

Just how long these units will last out in the field is not really known yet. The newer technology and materials have only been around for the last five or six years. Whether they remain functional over the next twenty years or so is something that only time will tell. It does seem, however, that manufacturers have incorporated lessons learned from the past. Their need to overcome resistance by the landscape business community, gun-shy because of past experience, continues to drive innovation.

Consider the benefit to your bottom line should these new devices actually save you time and money. Less time spent maintaining a site means more time spent growing your business. Put a toe in the water—install a few units on a trial basis. Some sensors are quite inexpensive, costing just $30 per unit.

The risk is small, but the payoff could be great for you, your business, and your clients’ water bills.

 
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