Nico’s Nuggets: Legal Outdoor Growing in Colorado

Hi Nico…. I live in Colorado. I have two plants. I have a plastic-type greenhouse where the doors and windows open with a zipper. Can I open the windows a bit to let out some of the heat during the day? I can put a lock on them so they can’t be opened any wider than I want. I’m confused about the Colorado regulations.  If I don’t open them, won’t things get too hot for the plants? Many thanks! – Linda K. – via

Greetings, Linda! And thanks for writing in!
To start, you are correct from a horticultural perspective – you need to effectively ventilate your greenhouse to prevent heat build-up. Excess heat and temperatures above 80 F will hinder plant development and begin to impede on photosynthetic processes. Air exchanges are also essential to garden health. Plants need fresh air and influxes of CO2 to stay happy and healthy.

Depending on your greenhouse structure, you may be able to modify the unit in other ways that do not lessen your security. For example, it is often recommended to exhaust your garden air near the ceiling where the temperatures are hottest. Creating small slits, flanges or circular cutouts can help in this regard. Attaching some screening to keep pests out and an inline fan to help exhaust heat could be one option. Be creative.

As for Colorado’s state regulations, I advise that you consult your attorney or give a call into the state’s Marijuana Enforcement Division (MED) for an exact interpretation of the regulations as I am not an attorney. That being said, let’s take a look at Colorado law and see if we can make sense out of it.

The regulations for legal, adult cultivation (for either medical or recreational use) stipulate the following;

  • Adult residents can grow up to six (6) marijuana plants per person, with no more than three (3) in the mature/flowering stage at any time. No more than twelve (12) total plants are allowed per residence, regardless of the number of adults living there. Marijuana plants must be kept in an enclosed, locked area.
  • Take extra precautions to ensure that only authorized adults have access to the marijuana plants. You must be 21 and older to have or use retail marijuana. Children and pets should be kept away from plants at all times.
  • Marijuana must be grown in a fully enclosed and locked space, whether indoors or outdoors.
  • Homegrown marijuana, no matter the form, may not be sold to others.

With that in mind, Linda, I would think that locked windows and doors would suffice as “an enclosed, locked area” even if the windows are open for ventilation purposes. I would further ensure the security of your garden by making sure the cannabis plants are not near the windows whereby they can be accessible from the outside (i.e., someone reaching through the window). If possible, I would suggest even keeping them out of view from the outside world (people like pot and may get ideas).

That being said, it is always a good idea to secure any outdoor garden space or greenhouse with a perimeter fence. While costly, this option would certainly satisfy most any state’s regulations for a secure outdoor cultivation site and would bring you quite a bit of peace of mind. If you deployed a printer fence with a locked gate, your options for greenhouse modification would be much more. Best of luck, don’t stress and keep on enjoying your right to grow your own at home!

Thanks for reading everyone and remember: Grow… And help the world grow, too!

Got questions? Email ‘em over to Nico at and be sure to put “Nico’s Nuggets” in the subject line!
1 comment
  1. Be mindful of street lamps as well, they can mess up flowering unless the plants are shielded. Source: next door neighbor and i discovered it with two different plant species, mine being of slight value.

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