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Evaluation of Recycled Materials as Hydroponic Growing Media

Lookup NU author(s): Nicole Kennard, Dr Ross Stirling, Dr Ankush Prashar, Dr Elisa Lopez-Capel



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Conventional soilless growing media, such as perlite, are mined from non-renewable resources and can only be disposed of in landfills after limited use. There is a need to investigate novel, sustainable growing media adapted from waste or engineered to be reused over multiple cycles. This study investigated waste almond shells and a recycled plastic drainage plank as hydroponic growing media alternatives. Physiochemical properties were evaluated, and a germination and greenhouse growth trial was conducted to understand the effect these media have on production and nutritional quality of lettuce (Lactuca sativa L. cv. Catalogna Verde). Drought testing was carried out to understand how the media affected the lettuce’s response to water stress. In comparison to perlite, yields under regular irrigation were reduced by 52% in almond shells and 72% in plastic planks, although lettuce grown in almond shells still obtained commercially relevant yields. Reduced yields in almond shells were likely caused by the shell’s high salinity. Lettuce growth in plastic planks was limited by impeded root growth and low water-holding capacity. In conclusion, with minor alterations, almond shells could be used as a sustainable growing media alternative to perlite in hydroponic lettuce production. More research is needed to manufacture the planks to be conducive to plant growth.

Publication metadata

Author(s): Kennard N, Stirling R, Prashar A, Lopez-Capel E

Publication type: Article

Publication status: Published

Journal: Agronomy

Year: 2020

Volume: 10

Issue: 8

Pages: 1-27

Online publication date: 28/07/2020

Acceptance date: 24/07/2020

Date deposited: 28/07/2020

ISSN (electronic): 2073-4395

Publisher: MDPI AG


DOI: 10.3390/agronomy10081092


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