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Sorghums

Forage sorghums are tall to very tall growing warm-season annuals that are generally harvested once for silage or green-chop. Sudangrass will grow to 5-6 feet tall and is much finer stemmed than forage sorghum. Sorghum-sudangrass hybrids resemble sudangrass more than forage sorghum, but has larger stems and leaves and higher yields than sudangrass. Both sudangrass and sorghum-sudangrass will regrow after each harvest, the number of harvests will depend on growing conditions and the length of the growing season. If the sorghum used is known to accumulate prussic acid, then grazing or green chopping should be avoided with immature plants, or after a killing freeze [GIS-19].

Forage sorghums are seeded at about 10-12 lbs/acre. Seeding rates for sudangrass and SxS hybrids are 10 to 20 lbs/acre, depending on moisture availability and seeding method. Seeding can be in rows with a corn planter, narrow rows with a grain drill, or broadcast and packed in with a roller. Sorghums should receive P and K according to soil test, and 40 to 80 lbs N at seeding. Some nitrogen (50 lbs/a) should be applied after harvest when expecting regrowth. Sudangrass and SxS should be harvested when they are between 36 and 48 inches tall, or have reached the boot stage. They will require wilting to achieve proper ensiling moisture. Millets are not the same species as sorghums, but are managed similarly. The do not contain any prussic acid, but are generally too slow growing under the relatively cool Northeast climate to consider here.