Research was conducted in Mayagüez, Puerto Rico, to determine the effect of two biostimulants on the in-nursery growth of 'Martinez' quenepa grown for rootstock. A brown alga (Ascophyllum nodosum) extract (Stimplex®) and a commercial blend of amino acids and related compounds (Macro-Sorb Radicular®) were applied to the rootstock container substrate as drench every three weeks until the plants reached the adequate grafting stage. Plants treated with the biostimulants were ready for grafting earlier than control plants. In general, 'Martinez' quenepa response to the amino acid blend was somewhat greater than its response to the (Ascophyllum nodosum extract, but the extent of growth response depended on biostimulant rate. Both biostimulants may be useful to accelerate the growth of quenepa seedlings for rootstock.