What is seaweed extract? SmartLawn Seaweed Extract is made from a type of seaweed called Ascophyllum nodosum. Seaweeds have been used as fertiliser for many decades, they have been shown to benefit turfgrass in numerous ways time and time again. Our extract is made from seaweed harvested and processed here in the British Isles. How does … Continue reading Why should I apply seaweed to a lawn?