Adjust sunflower planting to meet crop goals.
Agronomy Bulletin 60 ─ Sunflower Populations
Sunflowers are very adaptable and can be grown under different environmental and soil conditions. Several university studies illustrate how sunflowers planted at varying populations, depending on the environment, can result in similar yields. When determining planting populations, consider environmental, agronomic and marketing factors to maximize yield and profit potential.
Factors to Consider
- Annual rainfall and subsoil moisture
- Disease and insect threats
- Planting dates
- Harvesting options
- Market demands
- Consider typical rainfall totals. Sunflowers can tolerate drought under the right circumstances. Reduced populations of 15,000 plants per acre narrowly aligned at 12-inch spacing are better-equipped to handle seasonal dry spells and low subsoil moisture conditions. Conversely, fields in heavy rainfall areas are able to support 30,000 sunflower plants per acre.
- Factor insect threats into populations size. Risks of certain sunflower diseases and destructive insects can vary from farm to farm. Under wet conditions, plants in high-population fields containing high levels of nutrients invite more disease. Longhorned beetles also do more damage in high populations and can severely damage stalks and make plants more susceptible to lodging. However, sunflowers planted at lower populations are able to develop robust stems that help reduce lodging.
- Schedule planting dates strategically. Planting earlier in the season allows for more in-field drydown. When planting close to the final insurability date, growers can increase population sizes to obtain smaller individual heads, which dry down faster than larger heads. It is recommended when solid seeding to bump up planting populations by 2,000 plants per acre.
- Compensate for drying facility shortages, if necessary. Growers without sunflower drying facilities should plant higher populations, resulting in smaller heads, faster drydown and, ultimately, drier seeds at harvest.
- Factor in market segment. If the crop will be sold into the confection or dehull nonoilseed markets that require a larger seed size, plant for smaller harvested population of around 15,000 plants per acre. Meanwhile, population totals should be noticeably higher if planting for the oilseed market. Bear in mind that growers should plant a population rate 10 percent to 15 percent higher than the desired final crop size.
Planting population is one of the most controllable aspects of sunflower farming. Respond to your operation’s environmental demands and market goals accordingly. For more information, contact your local Mycogen Seeds commercial agronomist or trusted agronomic adviser.