Climate change

Industrial Hemp: reviewing history and hysteria

I research industrial hemp. As I discuss this with acquaintances, I’m usually met with two responses. One is excitement to hear about a potential up-and-coming crop. The other is a mixture of suspicion and hesitation.

When most people hear about hemp, they think of marijuana, the recreational drug. But “hemp” alone, or industrial hemp, refers to a different variety of Cannabis, one that doesn’t have enough of the psychoactive component THC* in it to cause a high. The hemp that I work on has less than 0.3% THC and is once again defined as an agricultural commodity.

bumpy soil with green sprouts and leaves coming out
Young hemp plants sprouting in the field. Credit: Haleigh Ortmeier-Clarke

Some History

Historically, hemp was grown for its strong fiber. This fiber was processed into strong ropes and shipping canvases. Hemp originates in China, where it was produced for thousands of years. Hemp was introduced to North America in the 1600s. It was grown widely across the United States in the early 1900s through the second World War.

It’s not just current-day people who confuse the two varieties of Cannabis. Between Prohibition in the 1930s and some other legislative actions, the confusion between the two varieties of Cannabis classified hemp into a drug category, like its cousin marijuana. The misunderstanding of some basic botany led to legislation that outlawed the farming of hemp.

Mature hemp plants that have started to dry down. They are a valuable fiber crop that is drought-resistant. Credit: Haleigh Ortmeier-Clarke

There is no recorded production of hemp in the U.S. after the late 1950s. This is a sad ending to the crop that once served as the source of strong, reliable rope fiber used by our military in WWI and WWII.

But hemp is a crop that can potentially benefit farmers – so in 2014, with much work by scientists and other groups, the US Farm Bill allowed research institutions to grow industrial hemp. The Agricultural Improvement Act of 2018 (2018 Farm Bill) went a step further, classifying hemp as an agricultural commodity and took it off the controlled substances list.

So, my research is not on an illegal drug! It’s on a grain and strong fiber crop that can potentially serve as a source of revenue for many farmers.

The Hysteria

Interest in hemp has been growing for years across the nation. However, legislation still differs between states and the federal government. There has been a lot of confusion over the legality of hemp as a crop, how it differs from marijuana, and its many potential uses.

woman with ponytail and glasses cutting tips off hemp plants
Haleigh Ortmeier-Clarke taking THC samples from her plots one week before harvest. Courtesy University of Wisconsin-Madison.

The un-fertilized flowers of some varieties of hemp are high in cannabidiol (CBD). The buds of the flowers look identical to those of marijuana. For this reason, many law enforcement agencies are opposed to further hemp cultivation for this reason.

Hemp grain has a high oil content and can be crushed to extract the oil. The oil is commonly used in cosmetics like lotions and hair and body products. It can also be used in cooking and as a carrier oil for CBD.

The hemp fiber itself is incredibly strong and is used in ropes, canvases, and even clothing. New and innovative uses for hemp fiber, like plastics and construction materials are constantly emerging. Hemp plants, when grown to maturity are much taller than marijuana. And, their stalk fibers are strong. Hemp can grow as tall as 6 feet or more, whereas marijuana tends to be slightly shorter.

With interest is so high to grow what is a “new” crop to many, supply has greatly outweighed demand. Markets have not had time to develop and those that do exist have struggled to set quality standards. This has left some growers with a harvested crop with nowhere to sell.

The Next Steps

Since hemp hasn’t been grown in the United States since the late 1950s, the knowledge base surrounding the cultivation of hemp as a crop is severely outdated or irrelevant. While most commodity crops have clearly defined best management strategies for agronomics, fertility programs, and pest management, hemp does not. Thus, unbiased university research focusing on this crop becomes of extreme importance to stakeholders. The novel research being conducted across the United States is resulting in a crucial advancement in our baseline knowledge for the hemp community.

Answered by Haleigh Ortmeier-Clarke, University of Wisconsin, Madison

*The chemical name for THC is delta 9-tetrahydrocannabinol. It is found in marijuana in much higher quantities than in hemp. CBD refers to the chemical cannabidiol; this is found in higher quantities in hemp.

Two hemp courses were offered recently by the American Society of Agronomy. The first is an introductory course; the second is on the economics of hemp. For more information visit:

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

8 replies »

  1. Has the biosynthetic pathway from ‘x’ precursor to delta 9-tetrahydrocannabinol been described?

    If so, have the genes/location been described?

    If so, are CRISP/similar gene editing techniques being applied to interrupt the synthetic pathway, eliminating delta 9-tetrahydrocannabinol?

    Why does the plant invest in production of delta 9-tetrahydrocannabinol anyway? What does it ‘do’ to make the plant successful in the survival and adaptability sense?

    • Hi – our blog has a different purpose than yours. It’s for the education of the general public, not a deep delve into science concepts. We encourage you to contact our blogger for more scientific discourse – and thanks for reading. svf

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