Tag, You’re It: Best Practices for Metrc RFID Tagging

Wondering about the details of how Metrc compliance RFID tags work, or best practices for using it in your cannabis cultivation facility, outlined below are common RFID tag susceptibilities and overall best practices for cannabis plant and package tagging.

 

Once you’re comfortable with RFID best practices you will want to consider compliance tools like Scout™ a Metrc RFID mobile reader and software. Growers are looking for ways to close the compliance loop and have real-time information about plants and inventory. Scout is proving itself invaluable as an RFID compliance tool in today’s increasingly competitive cannabis industry.

What is RFID?

To start at the beginning, “RFID” stands for “Radio Frequency Identification.” RFID tags emit a low-power radio signal with a unique identifier. Where you might scan bar codes at the supermarket to differentiate, say, deodorant from bananas, RFID goes a couple of steps further: each individual plant or inventory item has its own unique code, whereas each banana at the store does not. Unlike bar codes, no line of sight is required to scan RFID tags. You simply need to be in proximity to the item. Although RFID provides many advantages over bar-code, it does have limitations that need to be considered.

RFID Tags Primary Susceptibilities:

1

Optimal Performance

Keeping these considerations in mind will help Metrc RFID technology users achieve optimal performance of RFID plant and package tags.
2

Distance

A passive RFID tag’s read distance is limited by the size of the tag’s antenna. The tag used measure 1” X 4”. This tag will have a nominal read distance of 10 to 14 feet as measured in free space with no obstructions and with the best tag orientation.
3

Directionality

The way a tag is facing may change the read distance of a tag. Each tag has a front, side and top down view. The view in which a user sees the tag may change the distance of which the device will read the tag. Optimal read distance are achieved when a tag is facing the reader where the user can see the writing on the tag.
4

Metals

RF energy is emitted by the reader and harvested by the passive RFID tags which in turn is used to power and send the RFID tags signal back to the reader. When a passive RFID tag is used in proximity to metal the tag’s signal may be reflected by metal and may disturb or reflect the limited energy used by the tag. If a tag is placed on or is surrounded by metal the tag may not work. Performance issues due to metal is not a permanent state and only happens while the tags are in proximity or touching metal.
5

Liquids

Liquids can absorb RF energy. If an RFID tag is attached to materials composed of or filled with liquids, the liquid may absorb the RF energy being received by or transmitted from the RFID tags.
6

Tag Placement

As mentioned above RFID tags have a tuned antenna designed for a specific frequency (902-905 spread spectrum). If a user places two or more tags directly on top of one another the tags antenna may be “detuned” causing the tags to be unreadable. A minimal separation such as 1 to 2 centimeters is sufficient in preventing the detuning of the tags. The detuning of a tag is not a permanent state and only happens while the tags are touching.

Cannabis Packages

As directed by Metrc Inc, “the package should have the RFID tags attached in a visible location where the tag can be easily seen and scanned”. Metrc RFID Tags should not be placed on top of one another in a way that would have the tags detune each other. Simple placement so the tags to have minimal spacing will keep the tags readable. Please note, detuning is not a permanent issue and only happens while the tags are touching.
Avoid use of metal containers or enclosure or bags with a foil lining. This may not allow the tag to read. Clear plastic bags or plastic or containers with the tag securely attached to the outside in plain view is optimal. A bag with a foil back with a clear front will work a long as the tag is place on the clear front when the package is full.

Cannabis Plants

Metrc Inc. directs “that smaller plants such as a clone(s) or immature plant(s) utilize the attachment strap to hold the tag upright in the growth medium”. This will keep the Metrc RFID tag out of the growth medium that may be wet causing performance issues for the RFID tags. Please note that a wet tag may experience performance issues while wet but will achieve nominal performance again when dry.
Metrc Inc. directs “that when plants reach a viable point to support the weight of the tag and attachment strap, the tag should be securely fastened to a lower supporting branch”. This step is a very important step. A tag placed on the plant where the tag is attached to the stalk or laying on or covered by the growth medium may not read. If the medium is wet or the material is covering may cause the tags unreadable. This also puts the tags in a poor orientation for reading by the device.

Cannabis Compliance Metrc Tagging Overview

  • Always refer to your operating State’s Rules and Regulation

  • Keep tags exposed and clearly visible.

  • Keep tags away from metal.

  • Keep tags out of the growth medium.

  • Read tags when they are dry and not directly after plants have been watered.

  • Invest in an automated compliance tool like Scout

  • For more information about RFID, you can refer to the Metrc Inc. website (www.metrc.com) and download the whitepaper on how RFID works.

If you would like to learn more about Metrc, tagging & Scout our Metrc cultivation compliance tool. Schedule a demo today.