Halophytes’ cultivation is in its infancy, and there are many baby steps until it can be quantified as another category of sea vegetables together with seaweed. Seaweed Liquid Fertilizer (SLF) is an eco-friendly option for nutritional supplementation of vascular plants. During sugar kelp (Saccharina latissima) harvest, the lower parts (i.e. stipes and holdfasts) are left behind for a possible regrowth, but it is not known whether this biomass could be an alternative fertilizer or whether only the upper parts (i.e. blades) are beneficial for plant growth. Salicornia is the most promising halophytic genus for Marine Aquaculture, and Salicornia depressa is a spread species with no cultivation restrictions in New England. Our aim was to identify if sugar kelp fertilizer from distinct parts and concentrations might improve the agronomical features of S. depressa for the grow-out in hydroponics systems. In June, sugar kelp was harvested from the Integrated Multi-Trophic Aquaculture (IMTA) site of University of New Hampshire (UNH) and processed by filtration to produce a SLF (plus a preservative). Salicornia depressa was collected in a salt marsh (Research license RES 7403; Department of Natural and Cultural Resources Division of Forests and Lands), cultivated in covered Erlenmeyers with full Hoagland solution plus sugar kelp liquid fertilizer and placed in two Percival growth chambers (rotation every 3 days; Figure 1). Our experimental design was bi-factorial: seaweed parts (upper vs. lower) and seaweed concentrations (0, 0.5, 1 and 2%), five replications per treatment. Parameters were analyzed by Analysis of Variance (ANOVA). From all the agronomical features measured for S. depressa, root length was significantly affected by sugar kelp fertilizer. This shows that all the parts of sugar kelp for liquid fertilizer can reduce the root length of S. depressa in contrast with the control (Hoagland solution; 0% seaweed fertilizer). Our findings evidenced that sugar kelp liquid fertilizer did not enhance the growth, biomass or minimized the reproduction (i.e. flowering) of Salicornia. However, any sugar kelp part as liquid fertilizer might be used for Salicornia cultivation in hydroponics units to avoid root entanglement, for example in Nutrient Film Technique (NFT) system, without affecting commercial traits.