Grow sweet sorghum from varieties bred for juice, not grain sorghum, planting after the last frost with plants 4-6 inches apart in rows, and expect a 100-120 day season. Harvest the stalks in fall when the seed heads mature, strip the leaves, and take the stalks to the press, since the sugar is in the stalk juice and the stalk is the crop.
Sweet sorghum cultivation is the growing of juicy-stemmed sorghum varieties as a sugar crop, harvested for the stalk rather than the grain.
The Stalk Is The Crop
The sugar guide gives the growing instructions: use specific sweet varieties, not grain sorghum; plant after the last frost, 4-6 inches apart in rows; allow a 100-120 day growing season; harvest the stalks in fall when seed heads mature; strip the leaves. It does not give row spacing, seed rate, soil requirements, fertility or yield by stalk weight, so this page cannot supply them and does not invent them.
Worked Example: Planting Date
The 100-120 day season means the crop needs that many frost-free days after planting. Use the method in Planting and Harvest Windows: latest planting day = first autumn frost day − days to maturity − a margin. With illustrative inputs: first frost on 15 October (day 288), 120 days, 14 days margin: 288 − 120 − 14 = 154, which is 3 June (day 151 is 31 May). With a 100-day variety the date moves to 23 June. Compare these with the date when your soil has warmed after the last frost; if the window is shorter than the season, the climate is marginal for the crop.
What The Land Is No Longer Doing
An acre of sweet sorghum is an acre not in grain, roots or beans. At the guide’s 100-200 gallons of syrup per acre, the yield works out to 1.5-3.0 million kcal of syrup an acre (see Yield and Labor Requirements), within the range of the caloric guide’s staple crops, though the syrup has little protein. The pressed stalks go to animal feed, which returns some of the cost (Livestock Feed Conversion).
What You Need
- Seed of a sweet variety, saved or sourced (Seed Bank Management)
- A seedbed on warm, well-prepared ground, after the last frost
- A rotation plan (Crop Rotation)
- Labour for stripping leaves and cutting stalks at harvest
- The press and pan ready before cutting (Pressing and Boiling)
Method: Grow The Crop
Step 1: Prepare the bed. Check that the last frost has passed. Step 2: Sow and thin to 4-6 inches between plants. Step 3: Weed through the season. Step 4: As seed heads mature in fall, cut the stalks, strip the leaves, and move them to the press. Step 5: Weigh a sample of stalks and measure the juice, so that you have your own yield per acre.
Common Mistakes
- Planting grain sorghum by mistake. The juice is not sweet.
- Planting before the last frost. Seedlings are killed.
- Cutting before the seed heads mature. The guide’s harvest sign is mature seed heads.
- Cutting before the press, pan and fuel are ready. The guide gives no holding time for cut stalks, so do not test it.
Safety
Sorghum leaves and young regrowth can poison livestock
Young sorghum, and plants stressed by frost or drought, can release cyanide-forming compounds when grazed (recalled agricultural knowledge, not from this corpus). Do not turn animals onto young regrowth or stressed plants, and keep the stripped leaves out of the feed unless you know they are safe. Cut stalks with a sharp, controlled swing and keep others clear of the swing.
What’s Next
- Learn next: Pressing and Boiling — turning the stalks into syrup
- Combine with: Planting and Harvest Windows — dating the crop for your site