Evaluation of substrates for cucumber production in the dutch bucket hydroponic system

Authors: YANG, TENG - The Ohio State University; Altland, James; SAMARAKOON, UTTARA - The Ohio State University

Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2022
Publication Date: 1/27/2023
Citation: Yang, T., Altland, J.E., Samarakoon, U. 2023. Evaluation of substrates for cucumber production in the dutch bucket hydroponic system. Scientia Horticulturae. 308. Article #111578. https://doi.org/10.1016/j.scienta.2022.111578.
DOI: https://doi.org/10.1016/j.scienta.2022.111578

Interpretive Summary: Tomatoes, cucumbers, and other high-wire crops are commonly grown hydroponically in a Dutch bucket system filled with perlite as the growing substrates. While perlite is an effective substrate, it is difficult to dispose after use and there are other concerns with its environmental sustainability. The objective of this research was to compare regional and/or sustainable organic substrates with perlite for production of cucumber in a Dutch bucket hydroponic system. The substrates evaluated were sphagnum peat, medium grade pine bark (Bark-M), coarse grade pine bark (Bark-C), coir, and wood fiber. Organic substrates investigated showed superior performance in limiting waste drainage, increasing fruit yield, and enhancing fruit essential nutrient contents. Further investigation in fertigation formula, volume, and frequency, as well as reuse or ideal ratio of featured substrates, could be considered to optimize plant performance along with economic sustainability.

Technical Abstract: The Dutch bucket system is commonly used for production of high-wire crops such as tomatoes, peppers, and cucumbers in controlled environment agriculture. It is a hydroponic system that utilizes containers typically filled with perlite as the substrate. Perlite is a non-renewable material that can be difficult to dispose of after use. Furthermore, demand for regional and sustainable substrates is increasing. Our preliminary study showed growth parameters in vegetative and early fruiting stages of cucumber grown with five regionally accessible substrates are comparable to perlite. Thus, the current study evaluated the performance of five sustainable organic substrates as an alternative to perlite in the Dutch bucket system for the full production cycle of cucumber (Cucumis sativus ‘Picolino F1’). The substrates evaluated were sphagnum peat, medium grade pine bark (Bark-M), coarse grade pine bark (Bark-C), coir, and wood fiber. Leachate rates in Bark-M, coir, and peat were lower than perlite by 18.0%, 24.0%, and 38.1%, respectively. Plant leaf area indicated better vegetative growth of cucumber with wood fiber, but pine bark had higher yield and fruit quality than perlite. Bark-M resulted in greater yield and fruit vitamin C content, which were 23.9% and 48.3% higher than perlite, respectively. On the other hand, although Bark-C had a similar yield to perlite, its fruit mineral nutrient content including nitrogen (except wood fiber), phosphorus, potassium, calcium (except Bark-M and wood fiber), sulfur (except Bark-M and wood fiber), iron (except Bark-M), zinc, boron, copper (except wood fiber), and manganese (except Bark-M), as well as total anthocyanin and total phenols were highest among all substrates. In summary, the organic substrates investigated could provide higher cucumber yields and quality than perlite in the Dutch bucket hydroponic system.