The Ultimate Guide to Protecting Cannabis and Hemp from Wildfires

2020 was a banner year for wildfires in the western United States. Cannabis and hemp growers watched in fear as fires consumed more than 4 million acres in California — including several NorCal farms.

Now, as fires again threaten the West Coast, the farmers who lost crops in 2020 have a warning for others: Don’t underestimate the need for preparedness.

But how can cannabis and hemp cultivators protect themselves against wildfires? Without easy access to crop insurance, it seems all they can do is wait for destruction. There are, however, some steps you can take.

This guide combines expert sources and summarizes UC Berkeley’s recent report on cannabis, hemp, and wildfires. After reading, you’ll have important information about how to prevent damage, respond to fires in the moment, and mitigate smoke-tainted product.

Cannabis is More Vulnerable to Wildfires

A recent study by University of California, Berkeley — The Threat of Wildfire to Cannabis Agriculture in California — used some sophisticated methods to come to a simple conclusion: cannabis farms are more likely to be impacted by wildfires than other crops, and the problem is getting worse.

Researchers looked at historical fire data and licensee locations to find that cannabis grows are located in areas that are more likely to burn. 

It’s not rocket science. NorCal has more fires than the Central Valley, and more cannabis farms are located in NorCal (or in similar, mountainous regions in Oregon and Washington state).

What’s more, climate change is increasing the risk for cannabis growers. Software modeling based on Fire Hazard Severity Zones (FHSZ) and predicted climate scenarios shows that things will get worse for cannabis and hemp growers with every passing year.

Even if a farm isn’t directly damaged, smoke taint is a big issue in fire-prone locations. Smoke and ash change the taste and smell of the final product — and its market value. It also may cause failed tests at the lab, and it may impact growers hundreds of miles away.

What to Do to Prepare Cannabis Crops for Wildfires

Before fire season starts, take these actions to limit your liability.

Talk to Your Local Fire Department

Before fire season starts, get a fire-safety consultation. Most fire departments will come to your facility free of charge to offer insights into facility-specific problems and best-practice solutions.

A meeting lets you establish a relationship and let them know how to attend to your property in the case of an evacuation. Give them keys to access everything that could burn. Install a lockbox outside the facility to house the keys they’ll need in an emergency.

Manage Vegetation and Remove Debris

Grass fires spread along the ground from tree-to-tree so it’s important to clear grass and debris from your land. It also helps to prune trees higher up on the trunk. Without lower limbs, it’s harder for fire to climb the tree and spread.

Remove flammable debris or unused mulch materials. Stalks and trim should be processed with a cannabis and hemp shredder, or otherwise disposed of. Make sure to add these types of housekeeping tasks to your SOPs.

Crop Insurance?

Probably not. Cannabis growers don’t qualify for federal crop insurance programs and subsidies. Even hemp — a federally legal crop — has limited access to protection. 

Worse still, private insurers are decreasingly likely to offer cannabis policies. Insurance companies who offered cannabis crop insurance have suffered large payouts when farms burned.

Vineyards are able to access crop insurance for wildfires, but cannabis is different. Cannabis has a much higher market value and the same probability of burning — or a higher probability, according to the Berkeley study. That drives up premiums to 2X or 3X the amount paid by grape growers, making insurance impracticable for cannabis even if it’s available.

Cut a Fire Barrier

Fire can’t burn when there’s no fuel. That’s why the US Forest Service devises fire barriers, or fire lines, to separate areas with high burn probability or to conduct controlled burns.

Experts recommend scalping the ground around your facility seasonally, cutting a 40-foot wide bald down to the fresh earth. The more grass roots and biomass you can remove the better. This is one of the best defenses against direct damage (burned plants and buildings) but it won’t stop smoke contamination.

Get a Backup Generator

Utility companies will shut off power to an area in the case of a storm or fire. Cutting power protects firefighters from downed power lines and limits the potential for downed lines to start more fires in dry conditions.

Without power, you can’t run the essential cultivation equipment or security systems. Maintaining irrigation is critical in the heat of a storm and keeping the cameras recording is often a compliance issue. If you evacuate, you’ll want to maintain a visual on your property to see how it’s being affected.

Empower Your Staff

“Only you can prevent forest fires,” says Smokey the Bear— but your staff can help. Train them to address fire hazards and stop fires that may start on your property.

Equip them to fight small grass fires with the following tools:

• Boots that extend 8 inches above the ankle
• Vehicle-mounted water tanks
• Shovels and hoes
• Pulaski axes

Reconsider Your Choice of Cultivar

Wildfire season peaks in late summer and fall. Consider working with a strain that has a shorter flowering period. Saving just one or two weeks during peak fire season reduces your exposure.

Keep Water On-Site

A large water tank (1,000-5,000 gallons) gives firefighters what they need to protect your property during an evacuation. Make sure it has a firehose outlet and that the fire department is aware it’s there.

Protecting Cannabis and Hemp During a Wildfire

If a fire is in your area, consider these steps to protect yourself and your crop.

Contact the Fire Department

Notify the fire department that you are complying with evacuation orders and leaving the property. This assures them no people are in danger at your facility, and it also raises your hand for their services if the blaze heads in your direction.

Remind them of the location of your lockbox so they can access the property, as well as the location of any generators, fuel sources, or water tanks.

Reposition Sprinklers

Most cannabis farms use drip lines to deliver irrigant. But if you have a sprinkler system, you can aim it away from the crop — to the perimeter — to keep flames at bay.

Auxiliary sprinklers (even lawn-watering sprinklers) can help protect structures. If you’re evacuating, putting a sprinkler on the roof to keep shingles moist isn’t a bad idea.

Considering Tenting Your Plants

Even if your farm is spared, smoke and ash contamination can compromise crops and lead to testing failures. What’s more, ash from big fires can travel hundreds of miles before settling to the earth like snow.

Crude hoop greenhouses may help. Though tenting plants is an awkward solution, some 6mm polyethylene sheeting and PVC can keep the ash from accumulating.

Keep Embers Out

Close your windows and put screens over chimneys. Screens keep embers from entering and igniting your building.

Explore Moving Plants Off-Site

It’s worth asking regulators if moving some plants offsite is permissible. If so — and if you have a safe place to house your refugees — rent that box truck in advance.

Remediation and Recovery from Wildfire Damage

Few farms will be destroyed by wildfires, but many will be affected. Here’s how to recover from ash and smoke damage.

Understand the Problem of Contamination

Smoke taint is mostly an aesthetic problem. After the 2020 fires, testing laboratories were surprised to find that not many smoke-tainted samples contained contaminants — at least not the contaminants the state tests for. 

When man-made structures burn, lots of toxic compounds are released from the adhesives, treated lumber, plastics, and asphalt shingles. When trees burn, the smoke is much cleaner.

Testing labs expected to find  arsenic, lead, mercury, cesium, and iron. Instead, the smoke tainted product contained mostly carbonate — a relatively harmless ash by-product that’s not of concern to regulators. Yet nearby crops may pose problems. Ash and soot from pesticide-laden corn can cause test failures.

Creosote from tree sap is a possible contaminant from wildfires, but it’s mostly a quality concern. States don’t test cannabis and hemp for creosote, and it’s not a major health hazard. Again, it’s a matter of market value and aesthetics rather than consumer safety.

Like smoke-tainted grapes, smoke-tainted cannabis and hemp may be unsalable. Creosote or carbonate-tainted product tastes “off.” Some experts speculate that black market producers may be able to sell tainted product more easily than farmers selling through licensed dispensaries.

There’s a myth in the cannabis community that ash and rain can create lye, the caustic agent found in traditional soaps. Ash and water are the primary ingredients in lye manufacturing, but ash and water haven’t been shown to create lye that damages flowers. 

Some growers have had their flowers buried under an inch of ash without them being affected by toxins. The taste of the product, however, made it only usable for extraction.

Remove Ash

A layer of ash on your plants’ leaves slows photosynthesis and may inhibit CO₂ uptake. And you can’t sell product that’s layered in ash and soot.

After the fire, try removing ash with a leaf blower but be careful not to break branches or batter flowers around too much. Once most of it is off, you can spray them down on a dry day (or wait for the next rainstorm).

Market Contaminated Product

A badly contaminated crop may not be salable as loose flower. If so, it’s time for Plan B: extraction. The cannabinoids and terps are still there, and high-CBD hemp was likely headed for the extractor anyway.

If you test hot for your neighbor’s airborne pesticides, you may still be able to remediate the resulting oil. A glass reactor can distill out the water-soluble pesticides using a combination of polar and non-polar solvents.

Clean Up Your Site

Cannabis is a powerful bio-accumulator. It sucks heavy metals, radioactive materials, and pesticides out of the soil all too easily.

So, if it snowed ash at your farm, it’s worth doing some soil testing. A soil test can head off contaminant problems down the line. Knowing what’s in your soil will also help inform your choice of soil amendments for next year’s crop.

Without crop insurance, cannabis and hemp cultivators are exposed to serious risks from wildfires. Do what you can now! Prevention is always the best cure.

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