greenhouse sanitation

Clean And Green: A Cannabis Grower’s Guide To Grow-Room Sanitation

Cleanliness is next to godliness, as they say. And in a cannabis grow room, sanitation is critical to the overall success of your grow program. Yet, it often appears overlooked by many a grower, particularly the small-scale cultivators or those just starting out.

“Personally, I think it is horrifically overlooked,” says Christopher Sloper, consultant to the cannabis industry and author of The LED Grow Book: Second Edition. “I think what a lot of people look at is light and nutrients — ‘If I find the perfect light and nutrients…’ — and then people argue about pH because that is something easy, and then it kind of fades away and the environment isn’t thought of as it should be — and part of the environment is sanitation.”

Greenhouse and grow-room sanitation is a multifaceted endeavor that can reap big rewards — including fewer problems with aphids, mites and powdery mildew — or ultimately see the loss of your cash crop on the day you should be harvesting the bud bounty (and profits!) of your grow.

“Anything can break out with poor sanitation,” cautions Sloper. “I get a lot of calls [from growers] about inconsistent results; they’re on this roller-coaster ride and can’t figure it out. Part of that actually does start with contamination.”

OK, so enough doom and gloom. Let’s look at the bright side of sanitation. Sloper and his pal Jake Skokan, operations and product development manager at wholesale distributor of greenhouse structures and equipments ACW Supply, have provided a greenhouse-full of information that can have you on your way to a cleaner grow, better compliance, and ultimately higher profits.

greenhouse sanitation

Cannabis sanitation is a multifaceted endeavor that can reap big rewards, including fewer problems with spider mites.

Bust Out That Pressure Washer

Many growers are turning to abandoned warehouses, using LED lighting, and selective environmental controls in an attempt to grow those coveted big buds for their customers and patients. That’s all well and good, but it is critically important to clean these facilities thoroughly prior to planting the first seed or sticking the first clone. It’s also important to find out what the facility was used for prior to purchasing and starting a grow operation there. Sloper says one grow room he visited had been a diesel repair facility, with who knows what built up on the floors and lurking in the corners.

“Use aggressive chemicals to clean when opening up a new operation in a former warehouse,” advises Sloper, who also suggests bleach for this task. However, when it comes to day-to-day grow-room sanitation, he recommends using other cleaning products.

The same goes for cleaning up a greenhouse or warehouse after harvest, which unfortunately not all growers do. While pushing for profits, they simply get another crop going rather than turning the place upside down and cleaning every nook and cranny.

“One of the other mistakes I see is growers have multiple crops out in the same room. They’re taking this table down this week and that table down next week and there is no opportunity to sanitize it,” says Sloper. “So, they run these operations for years without taking the rooms offline to clean them and I think that is one of the most critical things in sanitation — you have to plan for some downtime.”

Products To Sanitize Your Grow Room Or Greenhouse

Keeping a grow room or greenhouse clean is even more of a challenge with cannabis than in an ornamental crop production situation. Most bedding plants, like petunias and marigolds, can be finished in about eight weeks, compared to 3–5 months for cannabis. The latter growing situation gives insects and pathogens a large window to attack your plants and cut into your time and profits. Therefore, keeping a grow room clean during this period is critical.

Fortunately, there are some excellent, albeit limited, products on the market to help you maintain a somewhat sanitary grow. Become familiar with the products that are allowed in your state and specific location. For instance, hydrogen peroxide-based products containing peracetic acid can be used during a grow cycle to clean up spills, and is safe for use right up until the flowering stage.

“Really, if you have a problem, you don’t have a lot of products to choose from,” admits Skokan, who adds that some of these products are OK for plants and surfaces, while some are not. If you do use cleaning products not approved for your grow, you do so at your own risk. “If they test chemicals in the plant because of drift, you’ll probably have to get rid of those plants.”

Prevention is key and Skogan says simple things, such as footbaths, making sure everyone enters the same door, plus requiring that visitors change into sanitary coveralls or aprons can go a long way in the management of biosecurity threats in a grow room.

There are three different categories of cleaning agents that are approved in Colorado and most likely in other cannabis-savvy states:

  • Peroxide-based products for day to day sanitation.
  • Quaternary ammonias as a hard surface disinfectant.
  • Acids and bases to remove mineral buildup.

Skokan says it is important growers study the labels on these products and use them accordingly.

Air Contamination In Closed-Up Grow Rooms

Stale, foul air could be classified as poor air sanitation. Clean, fresh air isn’t allowed to replace the stale air. In commercial greenhouses, air is often vented through the sides and top of the greenhouse. Not so in many cannabis operations, especially in converted warehouses. Pot growers often want to conceal the product they’re producing, or at least respect their neighbors, by using carbon filters, which can limit proper ventilation.

“That is something that some people might not be considering, the quality of the air,” says Sloper. “A lot of people keep facilities airtight, [so] a lot of toxic air can build up. An air exchange is needed for at least a little each day.”

He says this is particularly evident in warehouse grow operations.

“You see these grows,” Sloper continues, “everything is perfect: temperature, humidity, CO2, your nutrients are good, but your plants are just, like, bored.”

He recalls that in one grow where the cultivation team started to better vent the space, crop health improved dramatically. In fact, air quality can be improved and disease pathogens, such as those that spread powdery mildew, can be removed with the aid of an air scrubber, like this air sanitation system from AiroClean420.

greenhouse sanitation

(Image courtesy of @airoclean420)

Get Your Grow-Op Employees On Board

Having the best sanitation tools won’t do you any good if you don’t have employees committed to the cause. Commercial cannabis growers and licensed producers who are new to growing on a large scale may want to take some tips from fourth- and fifth-generation growers. Greenhouse sanitation has become second nature for these cultivators.

The growers in some of these larger operations set up protocols for sanitation, whereby each department has a checklist that includes:

  • Sanitizing pruners and cleaning their area every day.
  • Wearing lab coats and gloves when handling cuttings and other material in the greenhouse.
  • Frequent handwashing.
  • Using footbaths.

Perhaps the biggest challenge to this relatively new field of commercial growing is getting employees on board, so that sanitation eventually becomes second nature in the cannabis industry.

“You need to find good employees,” insists Sloper. “I tried to decentralize and it doesn’t work. You still need to check up on them, because sanitation is something people will skip out on. Yes, employees should be assigned to tasks, but management needs to follow up hard to make sure they are doing it, because employees will overlook a lot of that stuff — even simple things like water on the floor, or the accumulation of leaves, could be a breeding spot for something to go land in and lay eggs.”

Sloper admits sanitation is something that needs to be drilled into some employees, even those who have 30 years of experience. And he says some folks think that since they’re growing weed, they can come to work stoned, which he says isn’t how it works.

“It’s like, ‘No, if you want to do that, go home and do it at night. I don’t need you here.’ It’s a professional organization, it’s like, ‘Let’s go drink some beers and smoke and come back.’ I’ve dealt with that quite a bit.”

Ultimately, it comes down to communication. Conduct frequent scheduled meetings, even if for just a few minutes, to communicate what is expected from each employee and then follow up to see that things are getting done properly and in accordance with clear company policy.

Higher Standards Are Coming To The Cannabis Industry

Unfortunately, horror stories abound regarding grow rooms so dirty, you could write your name in the buildup on the sides of the greenhouse, Skokan reports. And in one grow room that he visited, Skokan encountered grease from a hamburger stand above the grow room that was dripping down on plants below.

To that end, Skokan recommends that players within the cannabis industry become more in tune with the safety standards present in the food industry.

“There was an incident where melons killed people and if we ever had such an incident in cannabis, that would change things,” he says. “The industry is somewhat in its infancy. More and more sanitation will be required as time goes on.”

Finally, here are some categories of cleaning products labeled for use in a cannabis grow:

  • H2O2: Hydrogen peroxide and peracetic acid makes a fungicide, bactericide and algaecide that’s safe to use up until flowering. Can be found in a product called ZeroTol.
  • Quaternary ammonias: Hard-surface disinfectant that works as a bactericide and fungicide. Found in KleenGrow.
  • Acids and bases: Non-caustic cleaner to clean surfaces where mineralization has occurred. Found in Horti-Klor.

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