White Proso Millet (70-100 days). Proso millet, also called Proso, grain millet or hog millet, is grown primarily in the US for feed grain or birdseed purposes. However, most of the world eats millet and it is becoming wildly popular in health food stores today. Proso is a warm-season grass and is well-adapted to the warm summer temperatures. It is, however, sensitive to frost and therefore usually is planted in June. ~5,000 seeds/oz.