Which of the following are types of non-soil media for nematode certification exemption?

Peat moss and perlite are both commonly used non-soil media that serve specific purposes in horticultural practices, particularly in the context of seed starting and growing plants in a way that minimizes the risk of transmitting nematodes. Both materials are lightweight, well-aerated, and provide good drainage, which is crucial for healthy root development. In terms of nematode certification exemption, these media are advantageous because they are less likely to harbor soil-borne pests compared to traditional soil.

Peat moss is an organic material that holds moisture while being free from pathogens, and perlite is an inorganic volcanic glass that helps with aeration and reducing compaction. This combination makes them ideal for certification purposes as they maintain plant health without the risks associated with soil contamination.

In contrast, options like rock and soil, dirt and mulch, and gravel and sand either contain soil or can have other organic materials that may harbor nematodes and diseases. Using non-soil media like peat moss and perlite helps ensure that the plants are grown in an environment that adheres to nematode-free standards required for certification.