Effects of Seed Density and Other Factors on the Yield of Microgreens Grown Hydroponically on Burlap

Abstract

Microgreens are gaining popularity as a new, nutritious salad crop. Growing microgreens in stacked hydroponic channels may improve efficiency and food safety for microgreens. However, differences between soil and hydroponic production methods for microgreens are not well known, especially when it comes to specific factors, like seed density, light exposure and yield for all the crops used as microgreens. This study explored the yield of six types of microgreens grown on burlap during three years of commercial production in a small educational greenhouse. The varieties, or species, tested in this study included basil, arugula, carrot, and blends of brassicas, radish and mustard. Seeds were sown directly on a single layer of burlap in a hydroponic nutrient film technique (NFT) system. Fresh weights (FW) of the microgreens were recorded after harvest to track the influence of seed density, light levels, growth time and season.

The mean seed density for arugula was 42.9 g·m-2, and 41.0 g·m-2 for basil, 57.8 g·m-2 for carrot, 55.7 g·m-2 for the mild blend, 51.5 g·m-2 for the mustard blend and 103.1 g·m-2 for the radish blend. Basil yields increased when temperatures were high in the spring and summer. In contrast, the mustard blend and arugula microgreens produced lower yields when grown in the spring and summer months compared to winter. Basil grew significantly better in full sun, and radish grew better on average when grown in the shade. The seed densities did not correlate with yield as expected. Light exposure and season appeared to be more influential to microgreen yields than seed density. When compared to other similar studies the seed densities, yields and growing conditions were diverse. This publication aimed to address a gap in knowledge on microgreen production methods.