Conduct a soil test and identify that the soil sample is for a field growing sweet sorghum and not grain sorghum
Dale, Della, KN Morris, Sugar Drip, Keller, Top 76-6, M81E, Simon, KY 1810, KY 08, Theis, Rox Orange, Umbrella, Early Orange are the most common varieties of sweet sorghum.
Sources of Sorghum Seed
Sweet sorghum can be direct seeded or transplanted. Small plots can be seeded using a push type seeder. Since seed size is different for each variety, some experimentation or calibration is required to obtain an optimum 2 to 3 stalks per foot. Soil temperature needs to be above 65 F for direct seeding and 60 F for transplanting.
The length of the growing season depends on the variety of sweet sorghum planted. From the time it is planted till harvest there are several factors to consider.
Fertilization - governed by soil analysis and it is often recommended not to use chicken manure or follow tobacco crops
Weed Control - there are few herbicides that are labeled to be used for sweet sorghum in controlling weeds. Contact your extension agent for more information.
Diseases - Anthracnose, stalk red rot, maize dwarf mosaic, downey mildew, and ergot are the most common
Insects - The insect that is most dreaded is the sugar cane aphid (SCA). Diligent scouting is required to prevent total loss of the crop. Special EPA exemption has been granted to most states in the past years to control SCA in sweet sorghum fields. Check with your county extension agent to determine in an exemption has been approved for your state.
Depending on the cultural practices of the producer, harvesting sweet sorghum occurs during the seed's soft dough stage.
Deheading - Some people may dehead the cane early to prevent lodging and increase Brix value of the juice. Deheading can be done mechanically or by hand using machetes or corn knives. Some producers cut the cane and dehead after it has been gathered using many instruments including chainsaws.
Harvesting - There are different methods of harvesting as most producers hand cut and let the cane lay for several days. Some producers use corn binders to cut the cane into bundles which aid in removing the cane from the field. Larger producers typically mechanically press the cane on-the-fly in the field.
Stripping Cane - There are several opinions of whether sorghum cane should be stripped before pressing but syrup contest results show that it doesn't matter.
Sweet sorghum syrup must be at least 74 degrees Brix to be sold as syrup.
Processed juice is typically allowed to settle for a couple hours prior to processing to allow for a cleaner cooking product. The settled material is not allowed in the pan.
Some producers use preheating the juice to a temperature range of 150 F to 185 F and then allowing to settle for a couple hours to allow the juice to separate and provide a cleaner juice for processing thus minimizing pan skimming.
Syrup can be processed in any pan style depending on what is available. Many small and new producers use a batch pan than hold several gallons of juice that reduces to a few gallons of syrup. Sorghum juice to syrup conversion depends on the sugar content of the juice, typically ranging 10:1 to 8:1. As producers become more experienced or increase acreage they will usually convert to a baffled evaporation pan. The heat sources are typically wood, gas, or steam.
Early Deheading of Sweet Sorghum, by Morris Bitzer, University of Kentucky
Several producers have asked about early deheading of sorghum prior to maturity. Early deheading will increase the level of sugar in the juice at harvest and reduce the chance of severe lodging from winds. The proper stage to dehead is critical as many new branches will form on top of the plant about 2 weeks after deheading and produce more seed. The head should be cut off at least below the top node. The best stage of maturity to start deheading is when the seed is in the Late Milk Stage. This is about 2.5 weeks before the stage for harvesting. Research showed that the Brix reading (sugar level) is lower when the heads are removed at a later stage of maturity.
Following was the average Brix levels at harvest when deheaded at the following stages: Bloom - 18.4 Early Seed - 19.4 Milk Stage - 18.4 Soft Dough - 16.7 Hard Dough - 14.6.
The Manufacture of Sorghum Sirup, Bulletin 90, A.A. Denton, USDA, 1901 reprint of 1899 edition
Sorghum Sirup Manufacture, Bulletin 135, A.A. Denton, USDA. 1908
Sorgo Sirup Manufacture, Bulletin 1389, USDA
Sorghum Sirup Manufacture, Bulletin 477, USDA, Bryan, February 1912
Sorghum Sirup Manufacture, Bulletin 477 Revised, USDA, Bryan February 1918
Farm Production of Sorgo Sirup, Bulletin, USDA, March 1938
Culture of Sorgo for Sirup Production, Bulletin 2100, USDA, February 1957
Sorgo for sirup production : culture, harvesting, and handling, Bulletin 1619, USDA January 1930
An Evaluation of Sorghum Syrup Processing Operations in Tennessee. Res. Rpt. 85-01, Univ. of Tennessee, Feb. 1985.
Sweet Sorghum Culture and Syrup Production. ANR-0625, Alabama Cooperative Extension Service, Nov. 1991.
Production of Sweet Sorghum for Syrup in Kentucky, AGR-122, Univ. of Kentucky, Feb. 1987.
Processing Sweet Sorghum for Syrup. AGR-123, Univ. of Kentucky, Sept. 1987.
Sweet Sorghum Production and Processing, The Kerr Center for Sustainable Agriculture, Inc., Poteau, OK, June 1992.
Growing Sweet Sorghum for Syrup. AGECON 99-055, Univ. of Georgia, March 1999.
Factors Influencing the Yield and Quality of Sorgo Sirup Produced in West Virginia, Bulletin 450, West Virginia University Agricultural Experiment Station, July 1961
University of Tennessee
-1997 Sorghum Series: #3 Victor Stoll
-1997 Sorghum Series: Sorghum Festival Demo
-1997 Sorghum Tour: Latch-HOST
-1996 A Tour of Three Sorghum Producers
-Selling Sweet Sorghum: A Marketing Video
University of Kentucky
-Sweet Sorghum Production, VAG-0736
If you are having trouble with starch in your evaporating pan burning and creating scorched syrup you may want to consider getting some amylase to add to your juice. If you are having trouble with some of your sorghum turning to sugar, you need to get some invertase enzyme and add it after you have heated it up.