What is considered a non-soil media that is exempt from nematode certification?

Bark is considered a non-soil media that is exempt from nematode certification primarily because it does not provide a suitable habitat for many soilborne pests, including nematodes. Unlike conventional soils, which can harbor various organisms due to their nutrient-rich composition and structure, bark serves as a substrate with different physical and chemical properties.

Bark typically has a coarse texture and lower water retention compared to soil, making it less conducive for nematodes, which thrive in more supportive environments. Therefore, using bark as a growing medium reduces the risk of nematode transmission and infestation in plant systems, leading to its exemption from certification requirements.

In contrast, sand, soil, and clay are all forms of media that can harbor nematodes and other potential pests, making them subject to certification processes to prevent their spread.