Marijuana grow lights can interfere with electronics

Marijuana thrives under artificial light, but radio enthusiasts say they are experiencing radio interference from grow light ballasts. Anza Valley Outlook/Diane Sieker photo

Amateur radio enthusiasts in the Anza Valley are reporting mysterious static on their radios, from base or home units to mobile CB radios. The intensity of the radio interference may be caused by marijuana grow lights – namely, the light’s ballasts.

Grow lamps are low-resistance units when lit, but they require a high voltage bump to get started. A ballast is a device that provides large enough voltage to get the light started, then regulates the amount of electricity going into the bulbs.

The American Radio Relay League, the national association for amateur radio, said that ballasts in many lights, such as the Lumatek LK-1000, can catastrophically interfere with amateur radio communications, notably in Colorado and California. Laws allowing the cultivation of cannabis in these states have compounded the issue, according to the league.

According to Interference Technology’s website, “Grow lights, which consume a large amount of electricity, are integral to indoor marijuana growing operations because they allow the plants to be grown in a controlled environment, leading to the production of a higher-quality product compared to outdoor operations. Since the legalization of pot in certain states, these indoor growing systems, known as grow houses, have increased in number, along with the number of grow lights.”

Local radio enthusiasts have reported loud and invasive noise emanating from certain locations in Anza and Aguanga. Driving past some residences yields incoming and outgoing interference, similar to driving past large light arrays, such as can been experienced near the Cahuilla Casino. Ballasts may be to blame.

“I had awful interference on my base station,” one CB radio operator said. “When the sheriff came and raided the neighboring greenhouses, the interference magically disappeared.”

The American Radio Relay League has received numerous complaints over the last decade of significant noise in the medium and high frequency bands between 1.8 megahertz and 30 megahertz. This interference is reportedly generated from grow light arrays housed in homes, outbuildings, greenhouses and even shipping containers.

Electromagnetic interference, also called radio-frequency interference when in the radio frequency spectrum, is a noticeable disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling or conduction.

Palomar Engineers, whose products suppress RFI/EMI interference from 100 kilohertz to 1,000 megahertz, said they offer solutions for growers to overcome this invasive noise.

Typical grow lights can be fluorescent, LED, high pressure sodium or metal halide. The HPS and MH lamps are available up to 1,000 watts each and require a ballast for proper operation.

Original ballasts were magnetic, but recent developments in switching power supplies have introduced electronic ballasts which are prone to square wave generation and can be rich in harmonics and RFI.

Unbeknownst to most marijuana cultivators, these electronic ballasts are subject to Federal Communications Commission Part 18 emission regulations, but many lights are imported from foreign countries that fail to test for these emissions per the requirements of the FCC rules.

These ballasts need to meet the consumer limits of FCC Part 18 in order to be legal for use in the United States.

Devices that do not meet these requirements can affect radio spectrum users including amateur radio operators, public safety users – fire, police, emergency vehicles and other first responders and even hospitals.

Reports of significant radio frequency interference from grow lights are becoming more and more common.

Grow lamp ballasts can make so much noise that anyone with a CB radio can drive by and guess what is going on inside a building. Growers trying to be secretive about their operations may not succeed when they are generating significant RF interference to radio communications.

Static noise from grow lights has been shown to be problematic at distances of over 1,000 feet. This amount is well over three times the distance that could be expected from a legal one that meets the applicable FCC limits. They are also commonly controlled by a timer, cycling on and off at precise times. RFI in the 40 meter ham band (7 mhz) is a good indication of a cultivation operation in the area.

There are solutions that can be incorporated into a growing program that uses lights.

Palomar Engineers offers a Grow Light RFI Kit for Digital Ballast, which suppresses interference to neighbors and nearby electronic devices.

The kit includes an RFI-Ballast kit with 1 ring filter on the AC input and another on the ballast lamp output side for each grow light ballast used.

As with any RFI problem, the solution of the “Source-Path-Victim” RFI problem is to eliminate or suppress the source, block the path or protect the victim device with various filters and chokes for the path to the victim, according to Palomar Engineers.

To lodge a complaint about grow light interference, contact the Federal Communications Commission at

Diane Sieker can be reached by email at