Dr. Russell Sharp explains how to choose and use microbial biostimulants for hydroponics, focusing on production/expiry dates, manufacturer credibility, and the trade-offs between liquid and powder formulations. He recommends trusted suppliers (Legume Technology, Omex/Biomex, Symbiom, Koppert's Trianum P), suggests starting with Bacillus blends and Trichoderma, and advises using seaweed extracts, humic acids and mild fertilizers to feed, not kill, microbes. https://eutrema.co.uk/shop/fertiliser/liquid-gold-unique-complete-fertiliser/ Ben Lugtenberg — Leiden University Jos M. Raaijmakers — Netherlands Institute of Ecology (NIOO-KNAW) Corné M. J. Pieterse — Utrecht University Paola Bonfante — University of Turin Ian R. Sanders — University of Lausanne Toby Kiers — Vrije Universiteit Amsterdam Uta Paszkowski — University of Cambridge Marcel G. A. van der Heijden — Agroscope Jan Jansa — Agroscope Marc-André Selosse — Muséum national d’Histoire naturelle (Paris) Francis Martin — INRAE (France) Jonathan D. Leake — University of Sheffield David J. Read — University of Sheffield Katie J. Field — University of Sheffield David Johnson — University of Aberdeen Mark Brundrett — University of Western Australia Sally E. Smith — University of Adelaide Suzanne Simard — University of British Columbia Nancy C. Johnson — Northern Arizona University Matthias C. Rillig — Freie Universität Berlin Katharine A. Horton — University of Canterbury Michael J. Ryan — University of Sydney Caroline P. P. N. “Caro” Veresoglou — Freie Universität Berlin Tim Daniell — The James Hutton Institute David E. Crowley — University of California, Riverside Egbert Schwartz — University of Arizona Sharon L. Doty — University of Washington Fitri A. Widiastuti — Bogor Agricultural University Bernard R. Glick — University of Waterloo Everlon C. Rigobelo — São Paulo State University (UNESP) Harsh P. Bais — University of Delaware Indranil Mukherjee — Indian Agricultural Research Institute (IARI) Dilfuza Egamberdieva — Leibniz Institute of Vegetable and Ornamental Crops (IGZ) Naveen K. Arora — Babasaheb Bhimrao Ambedkar University Rainer Borriss — Humboldt University of Berlin Blanca B. Landa — Institute for Sustainable Agriculture (CSIC, Spain) Philippe Lemanceau — INRAE Christophe Prigent-Combaret — Université Claude Bernard Lyon 1 Sonia Compant — AIT Austrian Institute of Technology Kornelia Smalla — Julius Kühn-Institut Angela Sessitsch — AIT Austrian Institute of Technology Gustavo Santoyo — Universidad Michoacana de San Nicolás de Hidalgo Roberto Kolter — Harvard Medical School Jeffrey L. Dangl — University of North Carolina at Chapel Hill Paul Schulze-Lefert — Max Planck Institute for Plant Breeding Research Marcel Dicke — Wageningen University & Research Wietse de Boer — Netherlands Institute of Ecology (NIOO-KNAW) Linda Thomashow — USDA-ARS (Pullman) David M. Weller — USDA-ARS (Pullman) Cheryl B. Anderton — Washington State University Gary E. Harman — Cornell University Matteo Lorito — University of Naples Federico II Sheridan L. Woo — University of Naples Federico II Christian P. Kubicek — TU Wien (Vienna University of Technology) Irina S. Druzhinina — TU Wien (Vienna University of Technology) Enrique Monte — University of Salamanca Charles M. Kenerley — Texas A&M University Sam E. Gryzenhout — University of the Free State László Kredics — University of Szeged Gábor Szakács — Budapest University of Technology and Economics B. A. Horwitz — Weizmann Institute of Science Alfredo Herrera-Estrella — LANGEBIO (CINVESTAV, Mexico) Alfredo Herrera-Estrella (Plant–microbe) — Irapuato Unit, CINVESTAV Antonietta “Tetta” Vinale — University of Naples Federico II Massimo Zaccardelli — CREA (Italy) Francesco S. “F.” Camera — University of Padua Antonio Di Pietro — University of Córdoba Fernando C. “F.” López-Bucio — Universidad Michoacana de San Nicolás de Hidalgo Pedro A. H. M. Bakker — Utrecht University Jasper F. van der Putten — Netherlands Institute of Eco