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Spring Planting Tips

Friday, April 15, 2005
filed under: Optimizing Plant Development/Yields

More treated sunflower hybrids will be planted this year, with Cruiser as a seed treatment option for early-season insect and disease control. But there can be seed flowability problems with treated seed. Thus, take note on whether your operator’s manual specifies to use a lubricant with treated seed, and if so, whether it should be graphite or talc – they are not interchangeable.

Generally, talc is used in vacuum and air planters, and graphite in finger pick-up planters. Check your manual to know for sure. Review the manual also for servicing recommendations, settings, depth control, optimum planting speed, and troubleshooting.

More sunflower planting tips:

Be sure to recalibrate – Do so every time you switch to planting a different variety, and even different seed lots of the same variety. Variances in per-pound seed count and/or seed shape can result in significant seeding error if you don’t recalibrate.

Soil temperature – A soil temperature of 50° or more at seed depth (1.5 to 2.5 inches) is generally needed for germination.

Fertilization – About 5 lbs of nitrogen are required for each 100 lbs of sunflower seed yield. Recommended rates of nitrogen fertilizer application will vary with the yield goal desired and the nitrate nitrogen soil test level. Where the soil has not been tested, a rule of thumb is to apply 3-5 pounds of nitrogen fertilizer per 100 pounds of expected yield. Apply phosphate and/or potassium fertilizer when soil test levels are low to medium for these nutrients.

Planting date in the Dakotas – The recommended planting window for the Dakotas is generally mid to late May. Early planting (May 15), usually allows for the best yield, oil, and test weight potential, as well as earlier maturity and hopefully warmer harvest weather. South Dakota State University research has indicated that oil is generally more affected by late planting than yield. Oil content generally begins to decline in sunflower planted after June 15, and yield generally begins to drop in sunflower planted late June.

Planting date in the High Plains – Sunflower can be planted in Kansas from early May to late June, according to the K-State University Extension Service. Generally, irrigated sunflower is planted in May and dryland sunflower during the first three weeks of June, according to KSU. Early plantings often result in larger seed size and higher oil, but they encounter more insect problems, and may require treatment. Conversely, late June and early July plantings are prone to smaller seed and lower oil, but fewer insect problems.

Seeding Depth – Sunflower should generally be planted at a depth of 1.5 to 2.5 inches and into moisture. Percent emergence will decrease as planting depth increases, especially for smaller seed sizes.

Seeding rate – Seed sunflower at a rate 10-15% above the desired final population, going with a lower rate if planting treated seed. Consider aiming for a final population of about 20,000-22,000 plants/acre for oils, and for the confection in-shell market that stresses seed size, 17,000-20,000 plants/acre. For the de-hull market, consider aiming for a final population of about 18,000-20,000 plants/acre, and for the bird food market where yield is most important, shoot for a final population of 21,000-23,000 plants/per acre.

Furrow Closing important – Sunflower needs to have excellent seed to soil contact. Because sunflowers have a woody hull, closure of the furrow becomes more important than for corn and most other crops.

Watch for hairpinning – At planting, check to make sure you’re knifing into the soil. Hairpinning – pushing chaff or straw into the seed slot instead of slicing through it – tends to be more a problem with air drills, particularly when seeding into no-till. Sunflower plants where hairpinning is a problem can have weak root systems and thus weak stands. Hairpinning is more of a problem when residue is wet – resolving the issue may be a matter of waiting until standing stubble becomes dry, and slicing through becomes easy. In other cases, you may need to sharpen drill discs/blades, or adjust down pressure.

Replanting Sunflower – Of course, when planting sunflower late (generally after June 10 in the Northern Plains) or replanting, use an early-maturing hybrid. The fact that sunflower performs well at lower populations suggests that replant is an option that might be best left for extreme early stand losses, especially in the shorter growing season of the Northern Plains. Some agronomists advise replanting only if a stand falls below a threshold of about 12,000 to 15,000 plants. Otherwise, you’d be losing two weeks of crop maturity, and the successful establishment of the replanted crop isn’t a guarantee either.

Sources: NDSU, SDSU, Mycogen Seeds

2005 Sunflower Treatment Options Online

A link to information on labeled seed treatment, herbicide, and insecticide options available to sunflower producers in 2005 can be found on the National Sunflower Association web site, On the home page, click on the link “Growers” then “approved chemicals.”

Crop pest treatment information can also be found at University and extension service web sites of these sunflower producing states:

Colorado State University

Kansas State University

North Dakota State University

South Dakota State University

University of Nebraska

Texas A&M

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