I haven't grown, nor do I partake, but living where I do, about half of my coworkers have been "in the industry" as their primary profession at some point in the last ten years. They have provided me a wealth of stories and knowledge about their former careers, including some of indoor grows v. outdoor/outbuilding.
The consensus among my coworkers is that rarely do indoor grows occur in an appropriately zoned/inspected industrial setting. A home will simply not be able to safely carry the load of the best lamps and ventilation for an extended period of time without substantial upgrades. Obviously, one lamp and six plants isn't going to do damage to your rental, but that also won't be enough to sustain a grow. The general contractor/former trimmer I work with is of the opinion that he would never grow inside a house due to the modifications necessary to avoid undue risk. He's of the opinion that its much easier to run appropriate electrical to an out structure through an upgraded box than anything else, which also serves to make ventilation/filtration and moisture concerns much easier.
What would this boil down to you for your rental? Here's my list of things to check up on:
- Get an answer from your insurance on whether damages would be covered, god forbid
- Get a reference or two from a former landlord or two that let them grow. I'm always amazed that more growers don't have enough cash on hand for a cheap house. I understand that its difficult to document such income (and many are unwilling to pay appropriate taxes), but with enough cash, BP has demonstrated you can make many things happen.
- Charge the max deposit, perhaps with an extra charge for certain services to be perfomed upon move out (check the rules for your state to make sure that's legal). Obviously, some professional cleaning will likely be needed.
- Don't lose sleep over the Feds. I live in a designated "Drug trafficking corridor" and the only people that get busted are the super grows on public land, the folks with other warrants, and those doing something stupid/annoying enough to get their neighbor to blow them in, such as stealing the last drops of water from a salmon bearing stream at the height of summer. Ensure that your tenant doesn't fall into those categories and you'll be fine.
- Make sure all steps are taken to be legal. Obviously, Colorado law is in conflict with federal law, but that doesn't mean permitting and appropriate display of permits, as well as zoning and such, should fall by the wayside. No need to be the guy that stands out from the grow house crowd.
- Consider turning a blind eye. Look into laws in your state regarding such culpability in the event of a fed seizure. I know in California, usually landlords are left alone, though they can have property seized under the law.
- Inquire as to how processing will be performed. Marijuana doesn't just drop off the plant ready to be smoked. Buds must be trimmed to remove unwanted bits before sale. Unfortunately for our landlord, usually the folks that trim aren't the most savory looking, so considering not allowing any processing on site if you allow a grow.
Good luck! Let us know what you decide!