Hemp is a variety of the Cannabis sativa plant grown specifically for industrial, nutritional, and wellness purposes. What separates it from marijuana is straightforward: hemp contains no more than 0.3% THC (the compound that produces a high) by dry weight. Both plants belong to the same species, but they differ at the genetic level, in how they’re cultivated, and in what they’re used for.
Hemp and Marijuana Are the Same Species
Hemp and marijuana are both Cannabis sativa L., a flowering plant in the Cannabaceae family. Most botanists treat cannabis as a single, highly diverse species with different forms rather than multiple separate species. The distinction between hemp and marijuana is based on chemistry, not a formal botanical split. Researchers in the 1970s proposed using the concentration of THC in the plant’s flowers as the dividing line, and that framework stuck. In 2018, U.S. federal law adopted a threshold of 0.3% THC on a dry weight basis to legally define hemp, removing it from the Controlled Substances Act.
Recent genomic research shows that hemp and marijuana are significantly differentiated across the entire genome, not just in the genes responsible for THC production. This means the two populations have been bred apart for so long that they carry broad genetic differences, much like different breeds of dogs that still belong to the same species.
What the Plant Looks Like
Hemp is a fast-growing annual that completes its life cycle in four to six months. Seeds sprout within four to ten days of planting, and the plant moves through vegetative growth, flowering, and seed formation before dying off at the end of the season. Its physical shape depends heavily on what it’s grown for.
Fiber varieties are planted close together, which forces them to grow tall and slender with minimal branching, maximizing the long fibers in their stalks. Roots can reach 90 to 200 centimeters (roughly 3 to 6.5 feet) deep in the soil, though the taproot itself often stops shorter and sends out thick lateral roots. Varieties bred for CBD or other cannabinoids are shorter and bushier, with more branching to maximize flower production. This bushy shape is closer to what most people picture when they think of a cannabis plant.
What’s Inside the Plant
Hemp produces over a hundred different cannabinoids, but its dominant one is CBD (cannabidiol) rather than THC. It also contains smaller amounts of cannabinoids like CBG. Fresh hemp flowers typically contain 1 to 3% terpenes by dry weight, with some high-terpene strains reaching up to 5%. Terpenes are aromatic compounds responsible for the plant’s distinctive smell. The most common ones in cannabis include myrcene (earthy, musky), limonene (citrusy), pinene (pine-like), linalool (floral, lavender-like), and beta-caryophyllene (spicy, peppery).
Hemp seeds, meanwhile, are nutritional powerhouses with a completely different chemical profile from the flowers. Three tablespoons of hemp seeds deliver about 10 grams of protein. They contain both omega-6 and omega-3 fatty acids in a ratio of roughly 2:1 to 3:1, which is considered favorable for human health compared to the much higher ratios found in typical Western diets.
How Hemp Is Used
Nearly every part of the hemp plant has a commercial application. The stalk has two distinct layers: long, strong bast fibers on the outside and short, woody fibers called hurds on the inside. Bast fibers go into specialty textiles, paper, and composite materials. Hurds are used for animal bedding, building composites, and lower-grade paper products.
Hemp seeds serve double duty as a food ingredient and an oil source. Whole seeds and hemp flour show up in nutrition bars, tortilla chips, pretzels, beer, salad dressings, cheese, and ice cream. Hemp seed oil is sold as a nutritional supplement in health food stores and used as an ingredient in body-care products like lotions, moisturizers, and shampoos.
The flowers are the source of CBD extracts used in oils, tinctures, and topicals. This segment of the market grew rapidly after the 2018 Farm Bill, though the FDA has continued to evaluate how CBD products should be regulated.
Hemp’s Environmental Role
Hemp has drawn interest as a tool for cleaning contaminated soil, a process called phytoremediation. Studies comparing hemp to other crops found that hemp produced up to 40% more biomass than sorghum and accumulated higher quantities of copper, lead, and cadmium in its above-ground tissues. That ability to pull heavy metals out of contaminated ground and store them in harvestable plant material makes it a candidate for rehabilitating polluted land, though the contaminated biomass then needs careful disposal.
The plant’s rapid growth cycle and deep root system also make it efficient at pulling carbon from the atmosphere, and its dense planting pattern means a single acre produces a large volume of biomass in a short season. Farmers in rotation systems value hemp for its ability to break pest and disease cycles for subsequent crops, and its deep roots help loosen compacted soil.
From Seed to Harvest
Hemp moves through four main growth stages: germination, vegetative growth, flowering, and senescence (the period where the plant matures and dies). After emergence, seedlings spend about three weeks establishing themselves before entering a rapid vegetative growth phase. Flowering timing depends on day length, since hemp is a photoperiod-sensitive plant that flowers as days get shorter.
Fiber hemp is typically harvested earlier, around or just after flowering, to capture the strongest bast fibers before the stalks become overly woody. Grain hemp needs additional time for seed development and maturation, roughly 40 days beyond the end of flowering. The total timeline from planting to harvest runs four to six months, making it possible to fit a hemp crop into a single growing season in most temperate climates.