Gracilaria salicornia, a common invasive algal species found in Kāneʻohe Bay, Hawaiʻi and around the world, is a potential potassium fertilizer source, but requires high application rates. This study evaluated the use of fresh and anaerobically digested G. salicornia as soil amendments at lower application rates than those required to provide complete plant nutrition to determine whether they increase pak choy growth and the efficiency of fish bone meal fertilizer. Fresh algae reduced the yield gap between low and high fish bone meal rates; however, these effects were only observed on one of two soil types tested. [ABSTRACT FROM AUTHOR]