In the Netherlands they start busting because of that. Too much smartmeter installed nowadays. It really depends on the size of the grow. I wish to find knowledge about significant numbers.
You'll want to insulate them. Maybe somebody else here could tell you if copper tape will work for your application, I've used them to insulate guitar cavities from EM.
Are you seeing this off the grid or is it when you have dimmers going.
Triac dimmers and controllers without enough snubbing will ring like that but a simple magnetic ballast should not be an issue. How many lights are you running.
This is the BEST info I have found on creating your own A/C and Lamp side filters. Super informative. Anything else you find on the web will be a watered down version of this.