Supporting Hydroponic Crop Growth using UV-C Light

Preliminary results indicate that intermittent exposure to UV-C radiation can enhance the hydroponic production of food crops by stimulating plant growth and inhibiting the growth of pathogenic organisms. However, in addition to its benefits, prolonged exposure to UV-C has been known to be harmful to plants (1, 2, 3). Watercress, a specie of aquatic flowering plant in the mustard family, was selected for this investigation. It is fast growing, can be eaten raw or cooked, and is rich in vitamins K, A, C, riboflavin, B₆, Ca, and Mn(4). It is closely related to the Arabidopsis sp. being studied for germination in lunar regolith(5).<br/>We designed and constructed a hydroponic system that exposed Watercress to commercially available grow lights and UV-C radiation lamps. By exposing the plants to UV-C in monitored 5 or 15 minute intervals we hoped to maximize its growing process and kill any pathogens while minimizing the damage done by the radiation.<br/>The watercress seeds were placed in net pots with moist growing medium and placed in a water-filled box and then exposed to grow lights. The plants were then exposed to five-minute of UV-C radiation followed by long periods of darkness. After each exposure to the UV-C, plants were observed and the growth and general characteristics of the plant recorded. After two days, the plants were exposed to fifteen-minute radiation intervals, following the same schedule. Each of the six boxes of plants underwent the same testing procedures for four days. The UV-C plants appeared equally as healthy as the control group but grew taller and tilted towards the lights more—exaggerated phototropism.<br/>At the end of the test, we observed mold growing in both the control and UV-C groups. Initially, we observed much more mold in the control group. After being untreated for a week, the group exposed to UV-C light had a considerable amount of mold compared to the control group. This difference suggests that during UV-C light treatment, the mold’s growth was curtailed. In conclusion, we believe<br/>the UV-C radiation did have a positive effect on the plants as we hypothesized.<br/>References<br/>1 Peters, R. March (2023) https://hydrogardengeek.com/uv-light-for-plants/ Accessed 9-2-2023<br/>2 Mishra, A Awdhesh K. (2020).. https://link.gale.com/apps/doc/A635206144/ Accessed 9-4-2023<br/>3 Buyanovsky, G., et al. https://doi.org/10.1007/BF02377118 Accessed 8-13-2023<br/>4 https://en.wikipedia.org/wiki/Watercress Accessed 8-31-2023<br/>5 https://moon.nasa.gov/resources/492/growing-plants-in-lunar-soil/ Accessed July 9 2023