Storage Techniques for Preserving the Integrity of Florida-Grown Biomass

Author: Georgie Smith

February 15, 2020

Controlling humidity, eradicating moisture and maintaining temperature are key to preserving the storage integrity of hemp biomass grown in Florida.

While Florida’s warm and subtropical climate is a boon for growing hemp, the weather does hemp farmers no favors when it comes to storage. Putting into place a drying and storage plan to offset Florida’s high humidity and temperature conditions will give Florida farmers the flexibility to keep their hemp biomass in good condition until they are ready to send their hemp to a buyer.

Moldy Hemp has Serious Consequences

Even if well dried after harvest, improper storage techniques can introduce a host of problems into hemp biomass. In the worst-case scenario, it can degrade into a wet, soupy mess that is obviously unsellable. More insidious (and common) however, is the growth of mold and fungus creating conditions favoring the production of mycotoxins.

Mycotoxins are common in many commodities grown in the U.S., including corn, wheat and soybeans. When found at high enough levels, they can have potentially fatal results for humans and animals.

Hemp biomass is tested for aflatoxins and ochratoxins and must not be test above 20 parts per billion.

Avoid Light, Oxygen and Temperature Fluctuations

Avoid open storage when storing hemp biomass. Exposure to UV light and high oxygen levels will result in rapid degradation of cannabinoid potency. Oxidation can even result in CBD converting to CBN, according to Hunter Heide, owner of H2 Processing, a hemp processing lab in Orlando.

Temperature fluctuations can also cause problems, potentially increasing humidity levels which may result in mold. Temperatures too low have been shown to degrade terpenes in cannabis.

The Perfect Climate for Storing Hemp? Not Florida

Hemp farmers in Western states and high-desert conditions with the luxury of drier, cooler climates have been getting away with storing their dried hemp in barns. Typically, with little to no temperature or humidity controls and absent extreme weather events, they have mostly been able to get away with that. But in Florida —the most humid state in the nation, a typical summer day will often reach 90 percent humidity — hemp farmers will not have a similar luxury.

The general rule of thumb for hemp storage is under 70 degrees and less than 30 percent humidity, but the cooler (above freezing) and drier the better, Heide said. At his lab, they typically store biomass they have received from farmers in walk-in coolers at 40 degrees.

The refrigeration process naturally removes humidity from the air as it cools, resulting in the ideal low humid conditions. Hunter has a strict policy of limiting entry into his walk-in storage spaces. Opening and closing walk-in doors can fluctuate temperatures inside the space, increasing humidity levels and introducing the possibility of mold growth.

Florida Weather and On-Farm Conditions Factor into Drying Techniques

On the Florida hemp farm, the first factor that will determine best storage practices will be how the hemp is harvested and then dried before going into storage.

Michael Dukes, Director of Agricultural Operations at Green Point Research, who has grown hemp in both Colorado and Florida, cautions Florida farmers to not attempt to swathe their hemp in the field like many western growers do.

“In drier, arid climates, we swathe it and wait two days. You can’t do that in Florida, it’s just way too humid,” Dukes said. In Florida conditions, hemp harvested and left in the field can be exposed to powdery mildew and botrytis within just 24 hours and then risk bringing that into storage.

Florida hemp farmers need to first decide will they hand-harvest and hang to dry (similar to tobacco curing) which gives them the potential option of other sales markets (such as smokable hemp flower). Or they can go straight to combining the entire plant in the field. Or hand-harvest for flowers and then combine.

If hanging, once completely dried the biomass (leaves and flowers) can be stripped from stalk and stored as is in supersacks. Or milled (chopped) and stored in supersacks. Milled biomass takes up much less volume, making it a space-saving solution that will be very useful for Florida farmers needing to move their dried hemp biomass into a controlled environment.

Un-milled, a supersack can hold about 300 lbs of hemp biomass. Versus milled, a supersack can store up to 2000 lbs of product.

If farmers elect to combine their biomass, they will first need to put the through a commercial drying process before milling and putting it into storage. Or take the risk of moving into storage a product with too much moisture content from the outset.

At this point, whichever harvest method was used, the dried biomass needs to be stored in a climate-controlled facility in Florida, Dukes said.

Many Florida farmers do have on-farm facilities that could be retrofitted fairly easily for hemp storage, they just may need to invest in the refrigeration. A $10,000 to $15,000 investment in appropriate refrigeration will be well worth the high value they will receive for their biomass, Dukes said.

Another option is the Orkel wet baling technology, which compresses, and wraps chopped material excluding oxygen preventing mold growth, Dukes said.

Heide also said he has seen sealed bales with a nitrogen insert to replace all oxygen, however noted that farmers may not be able to afford the more expensive technology for that process.

Heide said he does not recommend freezing hemp biomass, because once it starts to melt it will immediately introduce high humidity levels back into the biomass creating a potential problem.

About the Author

Georgie Smith is a life-long farmer and journalist who writes for, and about, the hemp industry – and its food, pharmaceutical, and fiber applications – to transform the American farm-scape. Georgie has been published in many places, including Hemp Connoisseur’s Magazine, and is available for content marketing, brand journalism, and thought-leadership writing services.

You can reach Georgie at:

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