Dry matter yield (DMY) is one of several important factors to consider in developing spices as a commercial field-grown crop. The objective of the experiments conducted with 4 species is to determine the effects of N, K, and micronutrients (alone and in combination) on the DMY of the spices. The spices under consideration are Ocimum basilicum (sweet basil), Origanum majorana (sweet marjoram), Origanum onites (pot marjoram), and Origanum vulgare (orogano). Field fertilization trials were established at the University of Florida involving four levels of N and three levels of K in a complete factorial design, and one level of a micronutrient package. Regression analysis of DMY indicates that spices responded most favorably to 168 and 252 kg N ha in combination with 168 kg K ha or alone, depending on the species. Plants responded poorly to K treatments when not in combination with N. Highest DMY of pot marjoram was obtained when micronutrients were applied in combination with N and K.