Monitor Moisture Wirelessly

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Growing up, you learn that relationships are built on trust. Growing in a greenhouse, you learn the relationship you have with your plants is also built on trust – mostly trusting yourself when it comes to knowing what your crops like and don’t like, need and don’t need. 

Hoogendoorn Growth Management developed a wireless monitoring system called Sensiplant that determines the soil humidity of your container crops, so you can trust your watering regime a little more. 

Humidity Matters

Sensiplant measures moisture in pots as a percentage, says Pete Hendriksen, North American sales manager at Hoogendoorn. “It determines what the moisture percentage is in a pot with various media, pot sizes and growing conditions. It’s wholly and specifically designed for the greenhouse industry.”
 
Sensiplant is made up of sensors, wireless routers, an access point (your greenhouse computer) and a software program that analyzes measurements. Simply explained, Sensiplant sensors/transmitters are placed inside the pot of a plant you choose to represent a section of your greenhouse. This sensor sends information regarding soil humidity to a centrally located wireless router in your greenhouse, which then transmits this collection of information to your site’s personal computer. There, you can see measurements of soil humidity in every irrigation zone you have applied sensors to.
 
“The wireless system works on low power consumption, a ZigBee wireless network,” says Hendriksen. Distance (approximately 20 feet) from the access point to the first sensor was an initial shortcoming for the system. “With the current hardware upgrade taking place, this distance will increase to upwards of 750 feet or more, depending on line of sight.”

Communicating Value

“I know a lot of growers who do a manual start with automatic sequencing, because they might not trust their ability to interface with the climate control computer they use,” says Hendriksen. “Sensiplant can help growers learn what their crop needs in terms of light sum, light intensity and time with this physical moisture test. Sensiplant also allows for if-and-or scenarios.” 
 
Rodney Bierhuizen, general manager of Ontario’s Sunrise Greenhouses, agrees. “Like on my staff, some people are wet growers and some people are dry growers,” he says. “If you come to the weekend and must rotate your growers, you can run into trouble if they have different growing styles.” Along with the system’s wireless mobility, Bierhuizen uses Sensiplant to keep his growers on the same page. “It quantifies watering,” he says. “Generally, when you ask a grower to tell you when he waters he says, ‘When the pot’s light.’ Now we have values on a computer screen.”
 

Put To Use

Olga Piedrahita has put the Sensiplant system to use in some “pretty rugged environments,” one of which involves vermicomposting (composting with worms). Piedrahita is an instructor for the greenhouse technician program at Niagara College.
 
Piedrahita’s students have used Sensiplant as a tool in a variety of small greenhouse projects. “We have used this wireless device with our wireless tensiometers, trying to find issues with wireless interference,” she says. “For our vermicomposting project, the Sensiplant receiver (access point) was 50 yards from the site and the signal was very good with no interference.”
 
Generally speaking, Piedrahita believes growers with multicrops set to different watering regimes can benefit the most from Sensiplant. “Watering is the most difficult job in the greenhouse, so if you have more knowledge about what you’re doing and when you’re doing it, I think that will benefit growers in quality and improve shrinkage,” she says.
 
When Bruce Jacobson, technical sales representative for Berger Peat Moss, first got his hands on the Sensiplant technology, he tried it at home on his houseplants. “It took me about 30 to 40 minutes to set up and install everything,” he says. Jacboson then began to use it in garden center trials to measure the moisture holding rate in Berger Peat Moss versus its competitors.
 
“The system will also help cut your fertilizer costs,” he says. “Growers will fertilize and then fertilize two days later when the plant might not even be dry. If you water unnecessarily, you just flush all the fertilizer out.”
 
One of his favorite features of the system is its ability to interface with multiple systems and not just those provided by Hoogendoorn. “It’s designed to be used with preexisiting systems, so you don’t have to throw everything away and start over with everything Hoogendoorn.”

Mihalek is a former Meister Media Worldwide editor.

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