Seaweed Extract Products Seaweed extracts from Ascophyllum nodosum have repeatedly shown their ability to promote yield and plant health in both scientific and on-farm trials. AlgaFlex, for example, is well established as a biofertiliser and as a plant biostimulant. As a biofertiliser, AlgaFlex is a balanced source of macronutrients, trace elements and organic carbon. As a biostimulant, AlgaFlex promotes physiological responses which exceed those explained by chemical nutritional analysis alone. Biostimulation induced by seaweed extracts includes improved flower and fruit retention, increased yield, stronger root system development and improved tolerance to environmental stresses and diseases. In addition, it increases populations and activity of beneficial microbes.