Germination temperature
Sow only when soil has warmed to at least 16-18 °C (60-65 °F); it is a warm-season grass.
Fodder crop growing guide
Sudan grass and sorghum-sudan grass are fast, drought-tolerant summer fodders that can be cut several times in one season. They are easy to establish in warm soil, but young growth can contain toxic levels of prussic acid (HCN), so knowing when to cut and graze matters as much as sowing.
Sow only when soil has warmed to at least 16-18 °C (60-65 °F); it is a warm-season grass.
1.5-3 cm (1/2-1 1/4 in); up to 5 cm (2 in) in sandy soil.
Seedlings emerge about 5-6 days after sowing in warm, moist soil.
None needed.
Do not feed or graze young plants: prussic acid is highest in the first 5-6 weeks and in regrowth.
Direct sow only, drilled in rows or broadcast.
Sow dry seed. Sudan grass seed is small, about 90-120 seeds per gram, so set a drill carefully or mix seed with sand for even broadcasting.
Not needed. The seed germinates readily in warm, moist soil.
Not needed. The crop has no cold requirement; cold soil is the main cause of poor stands.
Not needed. Sow into moist soil or irrigate after sowing.
Wait until soil is at least 16-18 °C (60-65 °F). Sudan grass suits warm conditions with moderate rainfall and does not tolerate prolonged cold or frost. In most of India it is a summer or kharif crop; multi-cut forage sorghums are sown from March to early May where irrigation is available.
Sow 1.5-3 cm (1/2-1 1/4 in) deep in heavy soil and up to 5 cm (2 in) in sandy soil. PROSEA advises no deeper than 2.5 cm (1 in) where moisture allows.
Grows on most soils, from heavy clay to sand, with pH about 6-7.5 (6.5 optimal). It tolerates some salinity and alkalinity but not waterlogging.
Sow into moist soil. For March-April sowings, the first irrigation is usually needed 15-20 days after sowing, then every 10-15 days.
The seed is covered; light is not required for germination. Grow in full sun.
About 5-6 days to emergence in warm soil; slower and patchier in cool soil.
Not transplanted. Drill in rows 15-50 cm (6-20 in) apart, wider in dry areas. Seed rates in sources differ widely: PROSEA gives 8-12 kg/ha drilled and 12-16 kg/ha broadcast for Sudan grass, while US extension services use about 22-34 kg/ha (20-30 lb/acre) for Sudan grass and sorghum-sudan hybrids. Use the higher rate for broadcasting and fine-stemmed hay.
Growth is rapid once established. Do not cut or graze before the crop is at least 45-60 cm (18-24 in) tall; Indian guidance for multi-cut forage sorghum puts the first cut at 55-60 days after sowing.
Cut again every 35-45 days, usually 3-4 cuts per season. Indian guidance cuts at 5-8 cm (2-3 in) above ground; US extension advises a taller 15-25 cm (6-10 in) stubble for faster regrowth. Irrigate right after each cut.
Cause: HCN is highest in young plants and new regrowth, peaking around 35-40 days after sowing, and rises with drought, frost or trampling. Fix: feed only after about 40 days or when plants are over 45-60 cm (18-24 in) tall, irrigate 2-3 days before cutting in summer, and do not leave chopped green fodder in a heap overnight before feeding.
Cause: stressed and frosted tissue releases HCN. Fix: wait 10-14 days after a killing frost, and after drought wait until plants recover and regrow to at least 60 cm (24 in) before grazing.
Cause: heavy nitrogen or manure, drought or cloudy weather lets nitrate build up; unlike HCN, nitrate does not disappear when forage is dried as hay. Fix: split nitrogen doses, and test forage from stressed crops before feeding.
Cause: sowing into cold or dry soil, or too deep. Fix: sow after soil reaches 16-18 °C (60-65 °F), 1.5-3 cm deep, into moisture.
Indian guidance for multi-cut forage sorghum is 100-120 kg N/ha in three equal doses: at sowing, after the first cut and after the second cut. On poor light soils add 8-10 t/ha of compost or farmyard manure before sowing.
For hay cut at about 75-90 cm (30-36 in). Prussic acid largely disappears during curing and ensiling, so properly made hay or silage is safer than fresh young forage; nitrate does not.
Sudan grass yields 20-40 t/ha of green fodder on average, roughly double with good fertilisation. It is drought-resistant, which makes it a useful hot-season fodder where irrigation is limited.
Order sorghum-sudan grass seeds for a fast, multi-cut summer fodder.
Not when it is young. Prussic acid peaks around 35-40 days after sowing; wait until about 40 days and until plants are at least 45-60 cm (18-24 in) tall, and treat regrowth after each cut the same way.
Usually 3-4 under irrigation: the first about 55-60 days after sowing, then every 35-45 days, irrigating after each cut.
Not quite. Sudan grass has fine stems, about 6 mm (1/4 in) thick; sorghum-sudan grasses are commercial crosses between sorghum and Sudan grass and differ in stem thickness, digestibility and prussic acid potential. Both are sown, cut and fed with the same precautions.