Apply nitrogen fertilizer to warm-season crops to promote growth. fertilize when corn is six inches tall and 24 inches tall; when cucurbits begin to produce runners; when eggplant, peppers and tomatoes begin to bloom (and again a month later); and beans one month after planting or when runners start to climb. Feed with nitrogen fertilizer for every 10 feet of row, apply one-third to one-half cup of ammonium sulfate or one-fourth cup of ammonium nitrate alongside the row a few inches from the plants and then irrigate thoroughly.