If this [material that never wears out] went on the market, it’d destroy the whole economy.
—MAJOR NELSON to Jeannie, I Dream of Jeannie
Oh, how easy our seminomadic ancestors had it with hemp. No composite strength tests or micron measurements. Just food (seed), shelter and clothing (fiber), and flower for get-togethers. Ya know, tri-cropping. But if you can get a professional-scale fiber project off the ground, bless you. For what? For the carbon sequestration you’re facilitating given the vast acreage necessary for a viable operation. You might even call your hurd product “Carbon Sink Hemp.”
In addition to livestock bedding and construction, a hemp fiber sector that’s about to explode is phytoremediation (soil building). Since both construction and phytoremediation are concerned with cleaning up past messes (cement plants alone contribute 5 percent of worldwide carbon dioxide emissions, and at least one-third of the earth’s soil needs some form of healing), here are a few more things to know about both.1
Carbon-Negative Living
Though we’ve been calling it hempcrete, a term conjuring images of heavy blocks, hemp building is already proving to be extremely varied: Hurd is being used for structural building, for insulation, paneling, and flooring.2 I’ve even seen engineers at Canada’s Composites Innovation Centre make a functional sound barrier wall out of it.
When we speak of hempcrete, it’s shorthand for hemp hurd mixed with lime (or other binder) and water.3 But we might see other modes of utilizing hemp for building, ranging from hemp-based spray insulation to digitally printed structures. In these cases, a key question to address is, “What are the binders and sealants?” The goal, remember, is not to be scared of the chemical-bath step in any industrial process.
The early modern hempcrete structures I’ve explored have all been highly functional—they can be virtually fireproof (blowtorching hempcrete videos are all over the net), and great for folks with chemical allergies. In Larimer County, Colorado, Melissa and Josh Rabe built (I mean personally built) a 1,500-square-foot hempcrete cabin at 6,200-foot elevation that I entered in a freezing rain in 2015. Inside, with no fire, it was toasty.
Part of that has to do with their attention to detail: There were no doorframe gaps, for instance. A lot of the R-value in any structure can depend on the quality of the build. But when done right, hemp building not only breathes, it regulates heat very well besides. The Rabes even stuccoed the cabin’s interior with hemp-cased plaster.
Natural building with hemp is also much less energy intensive during the actual build than concrete, drywall, and stick-frame building. Hempcrete doesn’t require the intense mixing heat that concrete does, for instance. And if the hemp feedstock is grown regionally, transportation energy use is much lower than drywall and lumber shipped across an ocean.
Hemp-built structures even continue working on climate change after you move in. “What is happening as the lime and hemp hurd fuse is they are capturing carbon,” said Patterson of Tiny Hemp Houses. If anything, Patterson explained, your walls are hardening as the hurd, in conjunction with its hydrolyzed lime, sequesters carbon.
The hempcrete industry was embryonic when I wrote Hemp Bound in 2013—there were perhaps a dozen hemp homes in North America. Today there is probably a hemp building specialist in your state. Indeed, last month I got cleaned out in a poker game by two-time NBA Hall of Famer Don Nelson at a gaming table set on a hemp floor in his hempcrete house in Hawaii.
It’s lovely that hemp hurd is in demand for building—that justifies investing in these expensive processing facilities—but it’s even better that it works. I knew hemp building was for real the moment my sons and I made a hempcrete ball in about 10 minutes. We used hemp we grew in Vermont, and lime sourced regionally. For three years that ball has traveled with me, in no special packaging, to nine states, three countries, and four tropical islands. Now, anytime I see someone building a green business storefront with pressboard, I think, What other species constructs its shelter out of things poisonous to it?
Despite its growth curve, hemp building is still in its early developmental stages. There is no one type of hemp structure—they can be as varied as the owner’s needs. Load-bearing structures will comprise different hurd-lime recipes than hemp insulation.4 This is why Sunstrand talks about offering fiber options to the micron. And here in the US Southwest, where I live, the adobe-like mixture will be different from the Manitoba virtual igloos that I profiled in Hemp Bound.
Set (or hardening) times for each layer of a structure will vary by climate as well, according to Patterson. It even matters what the weather is like on each morning of a build. Which kind of gets at the root of the issue with regenerative building: It’s not plug and play. And its implementation involves a lot of building code issues, which vary per region. We might not be able to (nor do we necessarily want to) map the Home Depot / subdivision mentality onto the biomaterials construction era.
Which makes it ideal for artisan builders such as the folks at Colorado’s Tiny Hemp Houses and Left Hand Hemp, Mexico’s Terrenos Tulum, Hawaii’s George Rixey, Idaho’s Hempitecture, Ukraine’s Hempire, and the pioneers Steve Allin and Hemp Technologies. It also means a hurd provider is going to have to listen to customer needs.
It’s not that hempcrete building, at its core, is that difficult. In fact, my job at the builds I’ve visited has been simple: just tamping the mixture into the hollow wood frames that encircle the rising structure. In the ideal situation, when you finish a two-foot-high layer of the structure, it has set sufficiently to allow you to move the molds on top of that level and begin tamping the next one.
The best and the most challenging realities embedded in hempcrete reside in its versatility. Each build will demand distinct ratios of the three basic ingredients. That soundproof wall I tested in Canada worked because the engineers jacked up the hurd ratio, leaving fewer of the air pockets that a builder might desire for insulating qualities. As a result, you could barely hear a roaring air compressor on the far side of that wall. Useful for folks who live near highways.
When it comes to those folks exploring the idea of 3-D-printed homes, or spraying building fiber out of hoses using the liquefied cellulosic components of the plant, these have promise, in the right situations, such as in or near urban centers. In the more remote, rural spots on the planet, though, a common problem with high-tech solutions to age-old problems is that when the tech side of the operation needs repair, the installers are usually long gone. That’s one reason I like solutions that can be done by hand or at least by accessible mechanical means. Even if it requires more brain power and muscle power on-site.
I do think 3-D printing of industrial components from hemp and other biomaterials will play a role in humanity’s near-term future, in applications such as body-friendly medical devices, regenerative roads, water filters, and compostable serving ware. Pulping biofiber for consumer items is not immensely difficult or expensive. Imagine every “disposable” cup and plastic fork suddenly winding up in garden soil instead of landfills. You could print your personally engraved coffee cup at the café, then get a dollar off every time you reuse it.
Hawaii, because of its remoteness, is the poster child for industrial independence: Everything not grown locally has to come from far away. The Aloha State will benefit when a $12 car part can be grown and printed instantly instead of hauled via diesel tanker halfway across the world. How fun it will be to reply, when asked at a cocktail party what you do for a living, “My co-op’s crushing it in regenerative toilet paper, truck bumpers, and lunch trays.” I’ll start gaining real confidence in the wider economic momentum shift to farm-grown industrial feedstock when both the rockets that SpaceX sends forth and the power cells that provide their energy are made from biomaterials.
It’s important to remember that hemp fiber can be a major contributor to the biomaterials feedstock effort, but it’s far from the only useful plant. This is especially the case when it comes to “waste” cellulosic material (fiber) for use in pulping applications like lunch trays, folding chairs, and serving ware, and in biomass energy. In Hemp Bound, we visited the Feldheim region of Germany, where municipal trucks pick up waste biomass from all the region’s farms to use in a gasification energy facility owned by the local agriculture cooperative. The region ended unemployment and gained energy independence by making use of what had once been considered trash.
I learned a lot about the broad array of helpful plants, algae, and fungi standing by for us out there in the soil, ready to join our biomaterials arsenal, when a European fiber salesman opened a briefcase in front of me at a Canadian convention. He looked like nothing so much as a hot watch seller in an alley.
The contents of the briefcase blew me away. He showed me about 40 different fiber swaths, including flax, kenaf, kapok, sisal, ramie, and vetiver, each with its own set of pros and cons: tensile strength, ease of cultivation, rate of degradation, fiber density. And all of which he could get for me in industrial quantities at low, low prices if I acted fast.
Which is good to know, because the real-world industrial marketplace has an amazing diversity of needs. If we think of just, say, shipment packaging, there is a wide range of strength, thickness, and stiffness that folks seek. Plus, we’re surely on the cusp of some new plant-based breakthrough. Next year’s killer app might prove to be an obvious-in-hindsight distillation of fiber lignin that provides the final demise of the cancer cell. Or maybe ground-seed-hull paste will reverse bee colony-collapse disorder. Maybe hurd, when mixed with tungsten and quinoa husk, will allow lightspeed travel or at least teleportation. After hemp’s ideal molecular-supercapacitor evolution, nothing going on inside a plant’s brain will surprise me.
Healing Soil
The other important hemp-fiber market that could very well prove to be a humanity saver involves doing nothing with the harvest: just planting and letting the hemp do its thing. And that market is phytoremediation. Ninety-three percent of US corn and soy acreage is planted with GMO agriculture (which only started in 1996, by the way), and 96 percent of India’s cotton acreage is GMO. This means that at least that percentage has an herbicide or pesticide such as glyphosate, 2,4-D, or atrazine to be cleaned up. Environmental remediation, in other words, is a major coming agricultural application in itself. In fact, it’s an industry projected to be worth $122 billion annually by 2022.5
I’ve gotten calls from folks at two different entities who work in environmental consulting, wanting to see where hemp might fit into their existing work cleaning up Superfund sites.6 A New Mexico State University researcher is using the Samurai cultivar in a mining-soil cleanup study as we speak. And hemp does have some existing research behind it as a soil cleaner. This is where Professor Qing Li comes in again.
In another preliminary study, Qing and his team found that 80 percent of atrazine in soil was removed 50 days after planting hemp. Further along is his team’s published study showing that hemp reduced the levels of chrysene, a polycyclic aromatic hydrocarbon (PAH) and suspected carcinogen found in coal tar and tobacco smoke, in soil after 28 days. PAHs, Qing’s paper asserts, “are often the most hazardous components of oil spills.”7
Folks who love hemp sometimes like to think that there is some magical component embedded in hemp’s biochemistry that makes it such a superlative phytoremediator. Qing is careful not to overstate the case.
“I think that people will not argue that hemp is a phyto plant,” he told me in a 2019 interview. “Why I can say that is that many plants can do the job: Chemicals will degrade, because plants will host microbes, and microbes will do their job. Is hemp better than others? Well, that is what we are interested in studying. The root is massive, which may prove beneficial.”
Don’t I know it. As a fellow who hand-harvested two crops in 2018, I’m well acquainted with how impressively strong those roots can be. But I’m so thankful for them—they are the architects of the underground ecosystem that we’re endeavoring to build: The fungi, bacteria, and the rest of our invisible friends appreciate the room to grow in their soil-based condo complex. It’s good to have friends in low places.
And please remember, if you aim to grow hemp and have any question about the history of your soil, do a baseline pesticide, herbicide, and heavy metals test before you plant. You might have to find more than one testing lab—one for nutrients, one for heavy metals, and so on. Equally important, please remember to only plant any crop intended for food if your soil is clean in these areas, and is at least three years from most recent application of an herbicide such as glyphosate or atrazine.
If not, plant hemp anyway. Just don’t eat it, or let your livestock eat it, or sell it to others. You can make this soil cleaning your business: US farmers know that much of their farmland is sick—they have to dump more than twice as much nitrogen on each year as they did in 1964.8 Europe has 3 million contaminated sites, the United States has 1,300 Superfund sites, and China estimates that 20 percent of its soil is polluted.9
Wanting to be clear about the importance of remediating-before-selling, I hesitate to mention this somewhat jaw-dropping postscript to Qing’s preliminary inquiry into hemp’s phytoremediative qualities. But he did tell me that it appears that hemp might in certain cases render some petroleum-based toxins inert even as it removes them from soil. Always cautious in his statements, Qing also pointed out that cleaning up heavy metals presents a different set of problems from the petroleum pollutants he has studied. So a lot depends on what exactly are the issues facing the soil.
Still, if this proves true in longer-term research, it is an immense breakthrough—it in fact helps answer the most common question I and everyone asks about hemp phytoremediation: “What do you do with the hemp once it removes toxins?” In other words, if hemp cleans up a mine site, an ex-GMO cornfield, or a nuclear spill, isn’t that hemp now contaminated? Part of the answer resides in mycelial and similar solutions that can break down soil toxins. But if hemp itself has chemical transformative properties, the world eagerly awaits further studies.
Examining the return of the biomaterials era from a higher altitude, I hope we’ve established the basic point that, from here on out, it’s imperative for every product of every kind in the worldwide industrial pipeline to be completely regenerative and healthy to everyone producing and enjoying it. This includes the farmers and customers of course, and also the packagers, the delivery drivers, and even, one supposes, the seed drill renters. If our paradigm-shifting intentions turn into manifestation, sooner rather than later, I think we fun-loving and sometimes lovable Homo sapiens might have a shot.
Whatever fiber apps wind up proving the smartest long-term play for a regional cooperative of independent farmers, it looks like we can’t get around the fact that we need at least 3,100 acres to feed a fiber-processing system. The cats will have to at least communicate, if not be herded. The technical learning curve involved in getting at the hurd, at least, is not insurmountable. But, as we’re about to see, making a co-op work in a way that keeps its members sane enough to continue working together can be.