Why Hemp Might Turn Into a Replacement for Peat Moss

How might hemp have a major role in the future of the horticulture industry? Here’s a look at how a byproduct of hemp can replace a common soil additive used by growers . 

What’s the Point of Peat? 

Peat moss has been and continues to be a common soil additive for the use of growing a wide variety of plants, whether agriculture- or floriculture-related. Found in most bagged potting soil mixes, peat moss is popular as an additive due to its ability to retain water and slow rate of decomposition. 

“It’s really hard to beat all the good qualities of peat moss for growing plants,” says horticulture professor Jessica Lubell-Brand. 

Used as a surface organic layer of soil composed of decayed vegetation and organic matter, peat is formed due to the incomplete decomposition of plant remains, according to Peatlands. This process (or lack of one) occurs in waterlogged conditions in locations with similar circumstances, including reduced nutrient and oxygen availability. Peat moss in particular primarily comes from wetlands, bogs, marshes, and swamps. 

The Environmental Damages of Peat 

While peat moss has plenty of benefits for stimulating plant growth, harvesting peat releases tons of carbon into the Earth’s atmosphere and completely destroys peat bogs; ancient ecosystems that are vital to regulating the planet’s climate. “It takes many thousands of years for a peat bog to develop, and when it’s harvested, you can’t really replace it,” says Lubell-Brand. 

Additionally, because of its popularity, peat is facing supply shortages. Byproducts of a dwindling peat supply have included rising costs and sales regulations to minimize its use and environmental impact, according to UConn Today. Many countries have banned the sale of peat to gardening consumers due to these concerns. Now Canada, the primary supplier of peat for U.S. supply stores, is weighing legislation to prohibit or restrict the use of peat. 

What Is Hemp Hurd? 

During the textile manufacturing process of hemp, the outer fibers of the hemp stem are spun into a cloth or rope. That leaves the stem, where a thick, wooden core is found inside. This byproduct, called hurd, is often discarded as waste. 

How Hurd Can Combat Peat’s Harm 

Lubell-brand, along with horticulture professor Mark Brand and graduate student Carla Caballero, has begun conducting trials with hurd. These tests were established after the pair of professors hypothesized that hurd’s similar composition to peat moss would help it replicate the additive’s growing effects. 

“With our studies with greenhouse crop petunia, we found that you can replace the peat up to 66% … and still produce a similar market-quality plant, in the same amount of time, with the same fertility,” says Lubell-Brand. 

This testing not only hints at a viable replacement for the peat, preventing the harmful effects of its harvesting practices, but also repurposes hurd, which is otherwise a large waste source disposed of within the hemp industry. 

The team plans to continue testing with other types of plants to see if the results are comparable, in addition to producing videos on the process to share the potential of hurd’s benefits with other growers and researchers in the field. Luckily, there already seems to be interest, as a pre-trial survey from SARE (Sustainable Agriculture Research and Education) Projects reports that 100% of surveyed growers “were extremely or strongly interested in research evaluating sustainable alternatives to peat.” 

Due to the speed at which peat is becoming a liability in horticulture, both regarding its dwindling supply and proposed legislation, research on hurd may be crucial in sustaining the industry. “Some of the largest nurseries in the state – let’s say, a 500-acre outdoor container production nursery – utilize about 17,500 cubic yards of peat annually,” says Lubell-Brand.  

A solution is needed quickly, and hemp hurd might be it.