"One of the main challenges in greenhouse nutrition is not the lack of data, but applying existing knowledge consistently and correctly across very different production systems," horticultural consultant Geerten van der Lugt says. He recently edited the fifth edition of Nutrient Solutions for Greenhouse Crops, which is available online now.
The manual supports nutrient management in greenhouse production systems worldwide, covering cultivation in soil, containers, and hydroponic systems using both inert and organic growing media. Geerten explains that the publication consolidates established fertilization principles with updated nutrient solutions and target values that reflect current greenhouse practices and analytical methods.
© Geerten van der Lugt
Crop coverage and system differentiation
Version 5 addresses the nutritional requirements of major fruiting vegetables, leafy crops, soft fruits, cut flowers, and potted plants grown under protected conditions. Nutrient solutions are differentiated according to growing system, recognizing that nutrient availability and uptake differ significantly between soil-based cultivation, organic substrates, inert substrates, and water-based systems.
The manual is divided into two main sections. Section A explains principles related to fertigation, root zone conditions, and nutrient solution preparation, including calculation examples using commonly available fertilizers. Section B provides tables with nutrient solution compositions and corresponding target values for root zone analyses.
Macronutrients are expressed in both mmol/l and ppm, while micronutrients are listed in µmol/l and ppb. For selected crops, the tables include adaptations for specific growth stages or production periods.
"Growers often work with a single recipe for an entire season, while the crop's nutritional demand is constantly changing," he notes. "The stage-related adjustments are meant to support more responsive fertigation strategies."
Linking nutrient solutions to analytical results
A central feature of the manual is the alignment of nutrient solutions with target values for different analytical methods. Whether samples are taken from irrigation water, inert substrates, organic media, or greenhouse soil, the manual provides reference values that help translate laboratory results into practical fertigation decisions.
The nutrient solutions are also suitable for recirculating systems. Guidance is provided on how to calculate nutrient supply concentrations based on existing nutrient levels, supporting both nutrient efficiency and system stability.
Several values have been revised in this edition, including tolerated sodium levels for specific crops and expanded explanations on working with NPK compound fertilizers.
"Recirculation and reuse of nutrient solutions demand a different way of thinking," Geerten adds. "Small calculation errors can accumulate quickly, which is why transparency in calculations is essential."
© YaraBeneficial elements added to the framework
"New in version 5 is a dedicated chapter on beneficial elements, with particular attention to silicon (Si) and iodine (I). These elements are increasingly applied in greenhouse horticulture, although they are not classified as essential nutrients," Geerten shares.
The chapter summarizes current insights into their potential effects on plant performance and provides guidance on their use in fertigation. The elements are not included in the standard nutrient solution tables but are discussed as optional additions to existing programs.
"There is growing interest in beneficial elements, but also a risk of unrealistic expectations," he explains. "The chapter aims to place their use in context rather than promote them as universal solutions."
From Dutch foundations to global application
The manual is rooted in the Dutch Bemestingsadviesbasis Glastuinbouw, published in 1999 by the former Research Station in Naaldwijk. While the underlying principles remain relevant, many nutrient values have been adjusted based on decades of field experience and the expansion of greenhouse production systems worldwide.
The first English edition of Nutrient Solutions for Greenhouse Crops was published in 2016, making this body of knowledge accessible to an international audience. Subsequent editions have added crops, refined nutrient solutions, and incorporated feedback from commercial greenhouse practice.
"What works under Dutch conditions does not automatically translate one-to-one to other regions," Geerten says. "Adaptation to water quality, climate, and production intensity is always necessary."
Collaborative development and practical use
The manual was developed through collaboration between fertilizer producers Yara, SQM, and Nouryon, analytical laboratory Eurofins Agro, and independent consultancy expertise. All nutrient solutions can be prepared using commercially available fertilizers from the contributing companies.
Input from technical specialists and reviewers was incorporated during the editorial process to ensure the manual remains practically applicable and scientifically sound.
"This publication is not meant to replace professional advice," he concludes. "It is a shared reference point that supports discussion, analysis, and better-informed decisions in greenhouse nutrition."
The fifth edition of Nutrient Solutions for Greenhouse Crops is available for download via the websites of the participating organizations and the editor.
For more information:
Geerten van der Lugt
[email protected]
http://geertenvanderlugt.nl/
Nouryon
www.nouryon.com
Eurofins Agro
[email protected]
https://eurofins-agro.com
