Hemp is a variety of the Cannabis sativa plant species grown specifically for industrial, nutritional, and therapeutic purposes. What distinguishes hemp from marijuana is its low concentration of THC, the compound that produces a high. In the United States, hemp is legally defined as cannabis containing 0.3% THC or less by dry weight. Above that threshold, the plant is classified as marijuana.
Hemp vs. Marijuana
Hemp and marijuana are both Cannabis sativa, but they’ve been selectively bred over centuries for very different purposes. Marijuana strains were cultivated to maximize THC content, which can range from 5% to over 30% in modern varieties. Hemp, by contrast, was bred for fiber, seed production, and more recently for CBD, a non-intoxicating compound. You cannot get high from hemp.
The 0.3% THC cutoff is a legal distinction, not a botanical one. A hemp plant and a marijuana plant can look nearly identical, especially certain strains bred for CBD-rich flowers. The real differences show up in chemical testing, growth patterns, and how they’re cultivated. Hemp plants are typically grown close together in large outdoor fields, producing tall, slender stalks. Marijuana plants are usually spaced apart to encourage bushy growth and maximize flower production.
Parts of the Hemp Plant
Every part of the hemp plant serves a commercial purpose, which is one reason it has been called a “cash crop to end all cash crops.” The major components break down like this:
- Stalks: The outer layer (bast fiber) produces long, strong fibers used in textiles, rope, and building materials. The inner core (hurd) is woody and absorbent, used in animal bedding, insulation, and hempcrete, a lightweight concrete alternative.
- Seeds: Hemp seeds are nutritionally dense, containing about 25% protein and a balanced ratio of omega-6 to omega-3 fatty acids (roughly 3:1), which is considered ideal for human nutrition. They’re sold whole, hulled, pressed into oil, or ground into protein powder.
- Flowers: The flowering tops of female hemp plants contain the highest concentration of CBD and other cannabinoids. These are harvested for CBD oils, tinctures, and extracts.
- Leaves: Less commercially valuable, but sometimes used in teas, animal feed, or composted back into the soil.
- Roots: Traditionally used in folk medicine and now being studied for compounds with anti-inflammatory properties.
How Hemp Grows
Hemp is a fast-growing annual plant that reaches maturity in 70 to 140 days depending on the variety and intended use. Fiber hemp is harvested earlier, while seed and CBD varieties need a longer growing season. The plant can grow 6 to 15 feet tall under favorable conditions, with fiber varieties reaching the upper end of that range.
One of hemp’s most notable agricultural traits is how little it demands from the land. It grows in a wide range of climates and soil types, requires less water than cotton, and naturally suppresses weeds because its dense canopy blocks sunlight from reaching the ground. Hemp also has deep taproots that help prevent soil erosion and can even pull heavy metals and toxins from contaminated soil, a process known as phytoremediation. This makes it useful for restoring degraded farmland, though plants grown for soil cleanup aren’t safe for human consumption.
The plant is dioecious, meaning individual plants are either male or female. For CBD production, farmers grow only female plants and remove males to prevent pollination, since seeded flowers produce less cannabinoid-rich resin. For fiber and seed production, both male and female plants are grown together.
What Hemp Is Used For
Hemp has an estimated 25,000 or more potential applications across multiple industries. The most commercially significant ones today fall into a few categories.
In textiles and materials, hemp fiber is stronger and more durable than cotton. It softens with each wash without degrading the way synthetic fibers do. Hemp fabric is naturally antimicrobial and UV-resistant. Beyond clothing, hemp fibers are increasingly blended into biocomposites for automotive parts, replacing fiberglass in door panels and dashboards for manufacturers looking to reduce vehicle weight and environmental impact.
In food and nutrition, hemp seeds and hemp seed oil have become mainstream health foods. Three tablespoons of hulled hemp seeds provide around 10 grams of protein with all nine essential amino acids, making them a complete protein source. Hemp seed oil is cold-pressed and used as a finishing oil in cooking (it has a low smoke point, so it’s not suited for frying) or taken as a nutritional supplement. Hemp seeds contain no THC or CBD since cannabinoids are concentrated in the flowers and leaves, not the seeds.
In wellness products, CBD extracted from hemp flowers is the basis of a massive market that includes oils, capsules, topicals, and edibles. CBD interacts with the body’s endocannabinoid system and has been studied for its effects on anxiety, pain, inflammation, and sleep. The FDA has approved one CBD-based prescription medication for certain types of epilepsy, but most CBD products are sold as supplements without FDA evaluation of their health claims.
In construction, hempcrete (a mix of hemp hurd, lime, and water) is gaining traction as a sustainable building material. It’s lightweight, breathable, mold-resistant, and acts as both insulation and a carbon sink, meaning the material stores more carbon dioxide than was emitted during its production. Hemp can also be processed into biodegradable plastics, paper, and biofuel, though these applications remain smaller in scale compared to established alternatives.
Legal Status and Recent History
Hemp cultivation was widespread in the United States through the 18th and 19th centuries. George Washington and Thomas Jefferson both grew it. The Marihuana Tax Act of 1937 effectively began restricting hemp along with marijuana, and the Controlled Substances Act of 1970 classified all cannabis as a Schedule I drug, making no distinction between hemp and marijuana.
The turning point came with the 2018 Farm Bill, which removed hemp (defined as cannabis with 0.3% THC or less) from the Controlled Substances Act and made it legal to grow, process, and sell nationwide. Individual states still regulate hemp cultivation through licensing programs, and farmers must have their crops tested to verify THC levels stay below the legal limit. If a crop tests above 0.3%, it must be destroyed.
Globally, hemp is legal to grow in much of Europe, Canada, China, and Australia, with varying THC thresholds. The European Union sets its limit at 0.3% (recently raised from 0.2%), while Switzerland allows up to 1%.
Environmental Benefits
Hemp absorbs more carbon dioxide per acre than most crops and even more than some forests, with estimates suggesting one acre of hemp can absorb 3 to 8 tons of CO2 during a single growing season. It matures quickly enough to allow double cropping in some regions, meaning farmers can harvest hemp and still plant a second crop in the same year.
The plant typically requires no herbicides once established because of its weed-suppressing canopy, and it’s naturally resistant to many pests, reducing the need for pesticides. Compared to cotton, hemp produces roughly double the fiber per acre while using significantly less water. As a rotation crop, hemp improves soil structure for whatever is planted after it, thanks to its deep root system and the organic matter it returns to the ground after harvest.