Over the past few years, we have seen growing interest in the use of biostimulants for sustainable agriculture (du Jardin et al. 2020). In addition, the ongoing European Regulation (UE 2019/1009) establishes the rules related to the registration and commercialization of plant biostimulants within the EU. Therefore, to officially register a biostimulant product, it is required to demonstrate its effectiveness reliably through scientific studies. In addition, many companies now are willing to characterize more specifically the mode of actions of their products. This is the goal of the LabCom SEASIDES, a joint, innovative laboratory that combines the expertise of two partners: the GlycoMEV laboratory (Glycobiology and Plant Extracellular Matrix - UR4358) at the University of Rouen Normandy, with a recognized expertise in glycomolecules and the private company, ALGAIA R&D Center, the main manufacturer of seaweed extracts in France. Multi-scale approaches (plant growth traits, water contents, chlorophylls measurements, cell imaging, monosaccharides analysis, molecular biology and RNAseq) are available in controlled and semi-controlled conditions on cultivated species with agronomical interest in order to assess biostimulant activities with or without drought stress. The proposed services can be offered to both private and academic laboratories.