Earth Day meets 420: studies suggest hemp could save the planet
The cannabis plant is multifaceted. Most products in the dispensary come from plants bred to produce high cannabinoid content, desirable buds, and particular terpene profiles. Hemp plants, on the other hand, are far more versatile in their use– from Farm Bill-compliant CBD products to fibers to building materials. Implementing conscious hemp cultivation could advance efforts in areas like soil phytoremediation, making the textile industry sustainable, and building green homes.
Hemp building materials expert Mattie Mead, CEO and founder of Hempitecture, explained to GreenState, “Industrial hemp as a resource for a variety of materials is a vehicle towards increasing sustainability, particularly within the built environment. Industrial hemp alone will not help us achieve climate or sustainability goals, but rather a comprehensive view of the problem at hand, and how industrial hemp may address it will best lead to hemp’s potential as a sustainable solution.”
Removing “forever chemicals” from soil
The colloquial term “forever chemicals” is used to describe substances that can exist in soil and the human body for years. Various studies suggest that while growing, hemp absorbs toxic contamination from soil. The USDA Western Regional Resource Center showed that industrial hemp could be a valuable tool in the phytoremediation of soil contaminated by heavy metals. Researchers showed that hemp could grow in soil with copper, chromium, zinc, and selenium and absorb the metals from the soil into its stalk and leaves. The study concluded that hemp could be a viable phytoremediation tool and recommended continued research.
The Swedish University of Agriculture Sciences Department of Aquatic Sciences and Assessment published a study comparing how sunflowers, mustard, and industrial hemp fared in removing PFAs from the soil. The hemp plants transported notable quantities of PFAs “from the root to their shoot”– promising results for heavily contaminated land.
Nonprofit climate news magazine Grist recently reported that the Aroostook Band of Micmacs have been growing hemp on land considered a Superfund site, aka so contaminated that the EPA marked the lot as high-priority for federal cleanup. The work of the Mi’kmaq people has proven the concept of removing PFAs from soil through hemp cultivation with “conservatively promising” results, according to a lead researcher for the Connecticut Agricultural Experiment Station, as reported by Grist.
Replacing or working with less sustainable fibers
The textile industry substantially contributes to chemical and water pollution, greenhouse gas emissions, and land use pressure. Environmental strain is caused by multiple touchpoints in the life of a garment—from manufacturing practices to microfibers leaching into the ocean after doing the laundry. Some clothing brands are exploring hemp fiber as a sustainable alternative to cotton. It is also common to mix hemp fiber with cotton, lowering the ecological impact of a garment. The growth cycle of hemp is shorter than cotton, takes less water, and leaves behind healthier soil than the cotton plant. These are all aspects of the hemp grow cycle that have less environmental impact than cotton.
Building a greener future, literally
Hemp could also contribute to greening the built environment where we live and work. Hemp hurd and other plant components can be manufactured into sustainable building materials that replace traditional materials like concrete and brick. But hemp-based building materials are rare in the U.S. construction industry, most likely due to the lack of approved hemp building codes. However, the 2024 International Residential Code approved the use of hempcrete in 49 states. But how does hempcrete compare to traditional building materials?
A 2021 study from the Universite de Lorraine in France assessed how hempcrete managed heat and temperature. Researchers concluded that “hemp concrete significantly reduces the energy consumption of the building and has better insulation properties than the two conventional building materials: brick and aerated concrete.” The same study showed that the hemp house had stabilized humidity and regulated air, creating a better ambience than conventional building materials.
To put it plainly, these findings mean that people living in hemp houses could see lower energy bills. A journal review of “hemp-based bricks” asserts that buildings made of hemp and lime absorb carbon dioxide from the air and maintain a stable acoustic level making for a more comfortable home.
These results present hemp-based building materials as a more environmentally-friendly alternative to traditional building materials. But a company is only as sustainable as its practices, Meade noted, “We designed our manufacturing facility to be energy efficient, using renewable energy as our energy source. It is not industrial hemp alone that makes our product sustainable—it’s the complete life cycle around it, factoring in our energy, inputs, transportation, miles, and the overall carbon footprint.”
What’s the downside, though?
It’s easy to wonder why industrial operations don’t adopt hemp materials when presented with this research. For farmers, there can be a learning curve when adding any new crop into the rotation. Hemp is no different. Hemp brings new pests and methodology. This learning curve is still present in the textile and construction industries but on a larger scale. For example, producing fibers from hemp as cotton has not been as economical. However, one study from the Rensselaer Polytechnic Institute showed that with technological advances, the price to manufacture hemp fiber could eventually equal that of cotton. It is also more challenging to dye hemp fabrics than traditional garments.
Hemp building materials face some challenges as well. Meade explained, “Hempcrete is a non-structural, non-load bearing material. Hempcrete lacks the compressive strength to be used as a foundation structural material, as well as a ground contact material with structural applications. While this may seem limiting to Hempcrete’s potential, it is not a concrete replacement and should not be thought of as such. Hempcrete is a versatile insulation material ideal for walls, floors, and ceilings, but all require the proper detailing to be well executed.”
A 2020 study from the University of Ottawa Civil Engineer Department showed that hempcrete blocks have a low compressive strength depending on the density of hemp hurd. Lower compressive strength blocks will require a frame for heavy loads. Meade added that contractor skills are an obstacle in American hempcrete adoption for built environments as reliable education for construction firms regarding how these building materials interact with a structure is only just becoming available.
With the obstacles in mind, it remains true that the hemp plant can do many things, and research suggests there may be untapped potential. As younger generations grapple with the implications of impending climate change, the possibilities of hemp could provide some hope– especially with impactful industrial innovation.