An 18-step protocol outlining precise methods for grinding kelp gametophyte biomass in laboratory settings. Details equipment options for both small-scale (microcentrifuge tubes) and larger-scale (tissue grinder) processing. Includes critical contamination screening steps, biomass transfer techniques, and proper grinding methods to maintain cell viability. Features specific warnings about contamination management, particularly regarding ectocarpus fragmentation risks. Essential reference for nursery technicians working with kelp propagation who need to process gametophyte biomass for culture expansion or experimental applications.