RFID Has Potential to Increase Production, Shipping Efficiencies By David Kuack

Imagine planting a crop, moving it into the greenhouse and knowing exactly where every plant is located right down to where it is on the bench. Even if the plants have to be moved to another bench or another greenhouse, you know exactly where they're located. In the greenhouse, you can control the irrigation, fertilization and any chemical applications specifically to each pot. Once the finished crop is ready to sell, you know where the plants are and can track them from your greenhouse to the delivery truck to the customer's door. Sound complicated? Sound expensive? Want to know more?

The potential of RFID

Radio frequency identification (RFID) is being used by many industries including manufacturing, shipping and transportation (i.e. E-ZPass tags and passports), medical and healthcare and animal identification. This technology has had limited applications in the horticulture industry, including being used for the identification and tracking of shipping carts.

RFID has been around since the 1970s and is similar to UPC barcodes. The biggest difference between these two technologies is that bar codes have to be able to be seen in order to be scanned. Since RFID uses electromagnetic waves, an RFID tag only has to be within range of an RFID reader. The RFID tag consists of a microchip and antenna.

Another issue with bar codes is they can't be scanned if they're torn, smudged or fall off. RFID tags are more rugged. They can be disabled if the label is torn or if the microchip is damaged. The RFID tags can also fall off.

Water is the biggest inhibitor of reading RFID tags. The reading range of RFID tags can be affected by higher humidity levels, water on the tags or materials, like growing media, with a high water content between the tag and reader.

Tom Fernandez, associate horticulture professor at Michigan State University, said RFID technology has the potential to be able to provide growers with support for a wide range of production and management issues. Based on the outcome of current and future research, RFID could do much more than maintain a more precise inventory of product. Fernandez said RFID has the potential to be used to manage chemical and irrigation applications and ensure more accurate product flow in the greenhouse, shipping area and customer delivery.

"The simplest application of using RFID is to track inventory," Fernandez said. "That can be done in production or throughout the whole value stream. The reason that we want to do this is because greenhouse plants are mobile unlike a lot of nursery field production. It's important for greenhouse growers to know where their plants are so that they can manage them appropriately and accurately. Growers will know what they have and where it is. The longer term goal is to look at RFID more as a decision support system than just a tracking system."

Production improvements

Fernandez said RFID tags could be used to identify the plants that need to receive specific production treatments, including irrigation, fertilization and applications of plant growth regulators, insecticides and fungicides.

"RFID can identify the plants in a data base to make sure that a treatment or whatever is being done is appropriate," he said. "For example, one of the things we hope to be able to do is incorporate RFID onto irrigation/ spray booms. As a boom moves across a bench it will identify the plants on the bench so that it adjusts irrigation and fertilization. As the boom, with a RFID reader attached, moves across a bench or the floor, the reader would read the RFID tags allowing a grower to change irrigation, fertilization and chemical application rates for the plants.

"The long term goal is to be able to do selective applications in a greenhouse or in a nursery. That is not something that can be done right now. We will be working with other universities, including some engineers and robotics people, so that we can integrate those types of efficiencies."

Fernandez said another benefit of RFID is that it provides traceability.

"As soon as a plant is tagged, a grower knows where it started and the location it is in. Once an integrated system is developed, a grower will also know what was applied to the plants during the production cycle. This can help internally with troubleshooting. If a client has a problem with the plants, a grower can check plants in the same batch that were shipped to other clients and whether or not they had problems. A grower can go back through a crop's production stages to determine if something was not done properly."

Fernandez said the same traceability provided by RFID could be used with the plant material coming into a grower's operation.

"A grower can trace the plants back to a supplier that may have been having a problem," he said. "This is going to save a lot of labor and the cost of data input and data transfer throughout the whole production scheme. RFID adds a greater level of accountability."

Inventory management

Just like with UPC bar codes, Fernandez expects the big box stores to eventually push the RFID technology be used by their suppliers.

"There probably is not going to be much choice just as these retailers demanded the use of bar codes be incorporated," he said. "Walmart tried to do RFID a few years ago on its inventory, but got push back from consumers who were concerned the retailer was trying to track them. The same thing occurred with UPC bar codes. People don't understand RFID technology and its limitations."

Fernandez said some retailers, like Bloomingdales, have promoted the benefits of RFID to its customers.

"Bloomingdales' flagship store in New York is using RFID for inventory management," he said. "The employees know what is in the stock room, what's on the sales floor and what just got sold. This enables the store to restock much more quickly. This also makes it much smoother to reorder from the company's warehouse."

Fernandez said there are multiple ways that growers can use RFID depending on what they want to track.

"A crop may get moved three to four times during a production cycle," he said. "The easiest way for a grower to identify where the plants are located is to track their movement through doorways. The RFID reader antennas can be set around doors that the crops have to move through. A grower will know whether the plants moved into or out of an area and where they were moved to. A time stamp is provided every time a RFID tag is read. Placing the antennas around greenhouse and shipping doors, a grower would specifically know what time the plants left the greenhouse and the time they were placed onto a delivery truck. The movement of the plants would be very easy to track by putting the antenna systems around doorways."

Tag printing, placement, price

Fernandez said RFID tags can be printed on just like any other label a grower might use.

"I have a TEC thermal printer and a Zebra encoder/ printer that I can use to print on RFID tags," he said. "Both printers can print identical visual labels on the same range of media. The Zebra machine can also encode the RFID chip of a RFID label. As the technology catches on, I expect the label companies will print RFID labels rather than most growers doing it in-house. These will be consumer-ready labels.

"RFID labels can also be printed with UPC bar codes so that they have both. This would allow growers and retailers to use both technologies. Dual purpose RFID readers are available that can read both RFID and bar codes."

Fernandez is conducting several studies with both greenhouse and nursery growers to determine the accuracy of the RFID readers under production conditions including the best location for the tags.

One of the studies was done with J. Frank Schmidt & Son Co., a wholesale grower of shade, flowering and specialty ornamental trees in Oregon.

"We looked at using RFID tags in postharvest when trees are bundled and put into storage," Fernandez said. "These are large trees, anywhere from a _-inch whip up to a 2_-inch tree. We used a key-hole tag that is slipped around a tree branch. The RFID chip is attached to the tag.

"We were able to get a 98 percent read in the postharvest study using the RFID tags. Then the nursery crew counted the trees. We compared the RFID tag counts with the nursery crew counts and there was basically no difference, both were 98 percent accurate. The advantage with RFID comes when employees don't have to start entering data into a computer. With the RFID tags all of the data is collected electronically."

Fernandez also did a project with Henry Mast Greenhouse in Michigan to study different locations for placing the RFID tags on containers.

"We have looked at labeling pots in various ways and reading the tags," he said. "We've had the best luck reading the tags when they are on the plants and not on the pot. Water can inhibit signal transmission. If a potting mix has 40-50 percent water-holding capacity. That's a lot of water that the signal has to go through. If the antennas are not placed properly, the tags are not going to be read very well.

"Putting a label on pots is currently not very effective. We want to work with a pot manufacturer interested in incorporating RFID tags into the containers. The advantage to that is the antenna could be throughout the entire pot. It wouldn't matter which way the pot is oriented because it could be hit with the RFID reader signal. The biggest problem is moving the signal through the potting mix. At Henry Mast Greenhouse we studied using adhesive RFID labels that could be attached to the inside side wall of the containers instead of the outside. We found this wasn't an effective way to use the labels because the potting mix inhibited the RFID signal."

Fernandez said controlling the tags is important to prevent stray tags from giving any false readings.

"One of the challenges with using RFID tags is keeping track of where they are," he said. "If a tag falls off, it will continue to be read until it is removed from that area. If a RFID stake is used and it falls out of the pot under the bench, the reader will continue to read that label in the greenhouse as long as the reader sees that tag."

Fernandez said an obstacle to incorporating RFID technology in most grower operations is the cost of RFID tags, which is too prohibitive for most growers.

"The polyethylene slip-on tags that we trialed cost about 20 cents each," he said. "Some of the large wholesale nurseries that we worked with that use this type of tag, said their price target is about 15-17 cents each. I expect that once the tag companies start manufacturing millions of tags, the price will come down substantially. Same thing with the latex tags which we have used with containers. These cost about 25 cents apiece. That's just not economical for most growers. Once the volume of RFID tags produced goes up, their price is going to come down."

For more: Tom Fernandez, Michigan State University, Department of Horticulture; (517) 353-0336; fernan15@msu.edu; www.hrt.msu.edu/ tom-fernandez.

RFID Has Potential to Increase Production, Shipping Efficiencies

David Kuack

David Kuack is a freelance technical writer in Fort Worth, Texas; He can be reached at dkuack@gmail.com.