ASHS 2025 Conference

Microgreens are young seedlings of various vegetable and herb species that are usually harvested 10 to 14 days after germination. They are a popular specialty crop because they are rich in mineral nutrients and health beneficial phytochemicals, grow quickly, need little space, and can be produced year-round in a protected environment. The choice of substrate is critical for successful microgreen production because it affects shoot growth, nutrient absorption, and total shoot yield. Compared with commonly used peat-based substrate, easy-to-use hydroponic mat products made from various fibers serve as sustainable alternative growing media. This study examines the effect of five substrates on the growth performance of four microgreen species including ‘Red Garnet’ amaranth (Amaranthus tricolour), ‘Red Gruner’ purslane (Portulaca oleracea), Rainbow Sprinkles Mix (with chard and beet, Beta vulgaris), and Shungiku (Glebionis carinata). The five substrates include bamboo mat, coco coir fiber mat, Ectone mat (made from recycled plastic bottle), jute mat, and a peat based soilless substrate. Results showed that fresh shoot weight was affected by the interaction between species and substrate type. Shungiku grown on peat and coco coir produced the highest fresh shoot weights of 74.7 and 70.2 g per growing tray, respectively, among all treatment combinations. Microgreens species varied in their preference of substrate for maximum shoot yield, with peat producing in higher fresh shoot weight than other substrate types in purslane and Rainbow Sprinkles Mix. Overall, peat and coco coir mat resulted in higher dry shoot weight than jute, bamboo, or Ectone mat across the four tested species. These results show the importance of choosing the right substrate for maximum yield and quality in microgreen production.