Sorghum requires warm soil and should be planted once temperatures consistently reach sixty degrees. Knowing when to plant sorghum is the single most important factor for a successful harvest. Plant too early, and cold soil will rot the seeds. Plant too late, and the crop may not mature before the first frost. This guide covers everything you need to know about timing, soil conditions, and regional variations.
Sorghum is a hardy grain that thrives in heat. It is similar to corn in its growing needs but tolerates drought much better. If you are looking for a reliable summer crop, sorghum is a strong choice.
When To Plant Sorghum
Timing is everything with sorghum. The exact date depends on your local climate and the specific variety you are growing. However, the golden rule is simple: wait until the soil is warm.
Soil Temperature Requirements
Do not rely on air temperature alone. The soil temperature at a depth of two inches should be at least 60°F (16°C) for three consecutive mornings. For best germination, aim for 65°F to 70°F.
- Use a soil thermometer to check the temperature.
- Check the temperature at the same time each morning.
- Cold, wet soil will cause seeds to rot or grow slowly.
Frost Dates And Your Last Spring Frost
Sorghum is extremely sensitive to frost. Even a light frost will kill young seedlings. You must plant after your area’s average last spring frost date.
- Find your local frost date using an online almanac.
- Add at least two weeks of buffer time after that date.
- Monitor the 10-day forecast for any cold snaps.
Regional Planting Windows
Different regions have different ideal windows. Here is a general guide for the United States.
Southern States (Texas, Oklahoma, Kansas)
Plant from mid-April to early June. The growing season is long, so you have more flexibility. Many farmers plant in May after the soil warms fully.
Midwest And Central Plains
Plant from late May to mid-June. This region has a shorter growing season, so early planting is critical. Choose shorter-season varieties if you are in the northern part of this zone.
Northeast And Upper Midwest
Plant from early June to late June. The window is narrow. You must use fast-maturing hybrids to ensure the crop matures before the fall frost.
Southeast
Plant from April to early July. The long, hot summers allow for a wide planting window. You can even plant a second crop for forage in some areas.
Factors That Affect Planting Time
Several variables influence the best planting date for your specific situation. Consider these factors carefully.
Sorghum Variety
Different varieties have different maturity lengths. Grain sorghum typically takes 90 to 120 days to mature. Forage sorghum can take 60 to 100 days. Sweet sorghum for syrup takes around 110 to 130 days.
- Short-season varieties: 70-90 days
- Mid-season varieties: 90-110 days
- Long-season varieties: 110-130 days
Always check the seed packet or catalog for the “days to maturity” number. Count backward from your average first fall frost date to find the latest safe planting date.
Soil Moisture And Drainage
Sorghum does not like wet feet. Plant in soil that is moist but not waterlogged. If the soil is too wet, wait a few days. Planting in muddy conditions compacts the soil and reduces germination.
Good drainage is essential. If your field has heavy clay, consider planting on raised beds or waiting until the soil dries out more.
Weed Pressure
Weeds compete with young sorghum plants for water and nutrients. Planting later can allow you to do a final tillage pass to kill early-emerging weeds. However, do not delay planting so much that you sacrifice yield.
How To Prepare For Planting
Preparation is key to a strong start. Follow these steps to get your field ready.
Soil Testing And Fertilization
Test your soil at least two months before planting. Sorghum needs nitrogen, phosphorus, and potassium. The ideal soil pH is between 6.0 and 7.0.
- Apply lime if pH is below 5.5.
- Apply nitrogen at planting time, about 30-40 pounds per acre.
- Side-dress with more nitrogen when plants are 12 inches tall.
Seedbed Preparation
Prepare a firm, weed-free seedbed. Till the soil to a depth of 4-6 inches. Break up large clods and remove rocks. The seedbed should be smooth enough for a planter to work evenly.
Seed Treatment
Consider using treated seed to protect against soil-borne diseases and insects. Many commercial seeds come pre-treated. If you are using untreated seed, you can apply a fungicide yourself.
Planting Depth And Spacing
Correct depth and spacing improve germination and yield. Follow these guidelines.
Planting Depth
Plant sorghum seeds 1 to 1.5 inches deep in moist soil. In sandy soils, plant slightly deeper, up to 2 inches. In heavy clay soils, plant shallower, about 0.75 to 1 inch.
If the soil is dry at the surface, plant deeper to reach moisture. But do not exceed 2 inches, or the seedlings may struggle to emerge.
Row Spacing
For grain sorghum, use rows spaced 30 to 40 inches apart. This allows for good sunlight penetration and weed control. For forage sorghum, you can use narrower rows, 15 to 30 inches apart.
Seeding Rate
The seeding rate depends on the variety and your goal. For grain sorghum, aim for 50,000 to 80,000 seeds per acre. For forage, you can plant 80,000 to 120,000 seeds per acre.
- Check the seed tag for the seeds per pound.
- Adjust for expected germination rate (usually 85-95%).
- Plant slightly heavier if you have poor soil or late planting.
Common Mistakes To Avoid
Even experienced growers make errors. Here are the most common pitfalls.
Planting Too Early
This is the number one mistake. Cold soil leads to poor germination and weak plants. Do not be tempted by a warm day in early spring. Wait for consistent soil warmth.
Planting Too Deep
Deep planting delays emergence and reduces stand count. The seed has limited energy to push through the soil. Keep depth at 1 to 1.5 inches.
Ignoring Weed Control
Weeds can choke out young sorghum. Use a pre-emergent herbicide at planting time. Also, consider a post-emergent application if needed.
Using The Wrong Variety
Choose a variety that matches your growing season. A long-season variety in a short-season area will not mature before frost. Always check the days to maturity.
Monitoring After Planting
Your job is not done once the seeds are in the ground. Monitor the field regularly.
Germination Check
Sorghum should emerge in 7 to 14 days, depending on soil temperature. If you see no seedlings after two weeks, dig up a few seeds to check for rot or insect damage.
Thinning If Needed
If your stand is too thick, thin the seedlings to the recommended spacing. Overcrowding reduces yield and increases disease risk.
Irrigation
Sorghum is drought-tolerant but needs water during critical growth stages. Irrigate during the boot stage and heading stage for best yields. Avoid overwatering.
Harvest Timing
Knowing when to harvest is as important as knowing when to plant sorghum. Harvest grain sorghum when the seeds are hard and the moisture content is below 20%. For forage, harvest when the plants are in the soft dough stage.
Use a moisture meter to check. If you wait too long, birds and weather can damage the crop.
Frequently Asked Questions
Can I Plant Sorghum In The Fall?
Fall planting is not recommended for grain sorghum in most climates. The plants need warm soil and a long growing season. In very mild winter areas, you might plant a fall crop for forage, but it is risky.
What Is The Best Month To Plant Sorghum In Texas?
In Texas, the best time is typically April through May. The exact month depends on your region. South Texas can plant in April, while the Panhandle may wait until late May.
How Late Can I Plant Sorghum?
The latest safe planting date depends on your first fall frost. Count backward from that date using the days to maturity of your variety. For most areas, planting after July 4th is too late for grain.
Does Sorghum Need Full Sun?
Yes, sorghum needs full sun for best growth. It requires at least 6 to 8 hours of direct sunlight daily. Shaded areas will produce poor yields.
Can I Plant Sorghum After Corn?
Yes, sorghum can follow corn in a rotation. However, watch for volunteer corn plants and manage residue properly. Rotating crops helps reduce disease and pest pressure.
Final Tips For Success
Planting sorghum at the right time sets the stage for a healthy crop. Use a soil thermometer, check your local frost dates, and choose the right variety for your region. Prepare your seedbed well, plant at the correct depth, and control weeds early.
With careful planning and attention to detail, you can grow a successful sorghum crop. The key is patience. Wait for the soil to warm up, and you will be rewarded with strong germination and good yields.
Remember that sorghum is a forgiving crop once it is established. It can handle heat and drought better than many other grains. But it cannot handle cold soil. So, do not rush the planting date. Your patience will pay off at harvest time.
If you are new to growing sorghum, start with a small plot. Learn how the crop behaves in your specific microclimate. Keep notes on planting dates, weather, and yields. Over time, you will develop a feel for the best timing in your area.
Sorghum is a versatile and valuable crop. Whether you grow it for grain, forage, or syrup, proper planting timing is the foundation of success. Follow the guidelines in this article, and you will be on your way to a bountiful harvest.
One last thing: always buy high-quality seed from a reputable supplier. Good seed gives you the best chance for a strong stand. Combine that with the right planting time, and you are set for a great season.