Supplemental light quality affects optimal seeding density of microgreens

Abstract Higher seeding densities can negatively affect the yield of microgreens. We quantified the effects of supplemental light quality and seeding density on the yield of microgreens. Seeds of red beet (Beta vulgaris L. ssp. esculenta) were grown in a greenhouse and provided with a narrow‐spectru...

Full description

Saved in:
Bibliographic Details
Main Authors: Isabela Scavacini deFreitas, Simone da Costa Mello, Krishna Nemali
Format: Article
Language:English
Published: Wiley 2024-01-01
Series:Urban Agriculture & Regional Food Systems
Online Access:https://doi.org/10.1002/uar2.20064
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Higher seeding densities can negatively affect the yield of microgreens. We quantified the effects of supplemental light quality and seeding density on the yield of microgreens. Seeds of red beet (Beta vulgaris L. ssp. esculenta) were grown in a greenhouse and provided with a narrow‐spectrum (or “purple”) and broad‐spectrum (or “white”) supplemental lighting at nighttime. Purple spectrum contained 90% red, 0% green, 10% blue, and 0% far‐red (R90: G0: B10: FR0) light, and white spectrum had 35% red, 42% green, 23% blue, and 0% far‐red light (R35: G42: B23: FR0). Each light quality treatment contained seeding densities of 50, 150, 300, and 450 g m−2. We measured fresh weight (FW) and dry weight (DW) on days 8, 10, 12, and 14 after sowing, relative growth rate (RGR), canopy area (CA), and chlorophyll (chl)a, chlb, betacyanin, and betaxanthin pigments. The optimal seeding density in the white treatment was 300 g m−2, whereas FW increased even at the seeding density of 450 g·m−2 in the purple treatment. The RGR of seedlings decreased with increasing seeding density but was higher by 27.8% in the purple than white treatment. The slope of the relationship between DW and CA (related to photosynthetic efficiency) was higher for the purple than white treatment (0.012 vs. 0.008 g cm−2). The ratio of chla to chlb (related to photosynthetic reaction center activity) increased by 15% in the purple than white treatment. Therefore, higher optimal density in the purple than white light quality treatment is likely due to increased photosynthetic efficiency of seedlings.
ISSN:2575-1220