Factors Affecting the Growth of Microgreen Table Beet

There are very few reports on the production of microgreens, a new category of salad crops, the shoots of which are harvested at the seedling stage. A series of cultural studies was conducted with the objective of lessening greenhouse production time and lowering production costs of microgreen table beet (Beta vulgaris L.). Sowing seed balls at a commercially recommended rate (201 g·m−2; 11,256·seed balls·m−2) resulted in greater shoot fresh weight·m−2 at 15 days after planting than sowing seed balls at lower rates, although individual shoots were lighter. Sowing seed balls that were germinated before sowing (pregerminated) in fine-grade exfoliated vermiculite moistened with 150% water (wt. per vermiculite dry wt.) for 5 days at 20°C resulted in 26% greater shoot fresh weight·m−2 at 15 days after planting than sowing nontreated seed balls. Combining preplanting fertilization of the peat-lite with calcium nitrate at 2000 mg·L−1 of N (150 mL·L−1of medium) with daily postplanting solution fertilization with 150 mg·L−1 of N led to a further increase in shoot fresh weight·m−2 of 21% (nontreated seed balls) and 22% (pregerminated seed balls) compared to other fertilization regimes (excluding the check). Germinating, and extruding, seed balls in hydrophilic polymer (hydroxyethyl cellulose gel) advanced microgreen growth but not to the extent achieved with vermiculite as the pregermination medium. Irrespective of seed ball treatment, producing microgreens in troughs using the hydroponic nutrient film technique, compared to production in trays containing peat-lite, increased shoot fresh weight·m−2. Depending on seed ball treatment, economic yield was increased 33% to 98% by 7 days after planting and 75% to 144% by 15 days after planting. The greatest shoot fresh weight·m−2 at 15 days after planting (10.14 kg·m−2) was achieved using seed balls pregerminated in moist vermiculite and subsequent growth using the nutrient film technique.