How to grow a successful crop of sunflowers this spring

Neil Groom, general manager of Grainseed, said that there has been significant interest in grain sunflowers. “Bella is an early-maturing variety and is the best-performing variety in trials and commercially in the UK.

“Climate change and increasing temperatures mean that the geographic area suitable for growing sunflowers is expanding in the UK. Sunflowers are best suited to areas that will accumulate at least 1400-day degrees over a base of 6 °C.

“They used to be grown south of a line from the Wash to the Bristol Channel, but now areas to the north and west can be considered. I can see sunflowers really flourishing in the UK within 5 years, and early adopters can try out this great alternative spring crop in 2026.”

Mr Groom, who has vast knowledge and experience of growing sunflowers and is responsible for the Grainseed trials, added: “In the UK trial, we have seen varieties that were too late to harvest, others that did not yield enough and some that were too tall and needed expensive growth regulation. Our variety Bella is well-suited to the UK and was the highest-yielding variety in trials.”

One in four years rotation

The expert explained that sunflowers can be grown on any free-draining soil type, with an optimum pH of 6.5 to 7.5. Growers should avoid high-pH soil, potash-rich clay and clay-loam soils. Open and sunny sites are well suited for growing sunflowers. Sunflowers are drought tolerant but require good soil structure, so growers have to remove any areas of compaction to allow good rooting. Sunflowers should not be grown on a rotation closer than one in four years to prevent diseases, such as Sclerotinia, from building up in the soil.

“Avoid any fields where previous crops of oilseed rape crops have suffered from Sclerotinia in the past. Do not follow sunflowers with potatoes. Seed is treated with a fungicide to protect from damping-off and seedling blight,” Mr Groom added.

Sunflowers should be drilled between the 10th and 20th of April at a depth of 3 to 5cm into a warm, moist seedbed. Typically sowing in mid- to late April will mean that they can be harvested in mid- to late September.

Mr Groom continued: “Take your time to drill properly. Sunflowers are sown at 110,000 seeds/hectare or 120,000 seeds/ha on heavier clay soils to achieve a population of 100,000 plants/ha on a 25-45cm row width. The seed rate is important, as it governs the seed head size, with higher yield coming from smaller heads that are easier to thresh.”

Pigeons can be problematic for the first 10 days post-drilling. Slugs at the seedling stage can also be a risk, so growers should monitor regularly and, if numbers are high, use slug pellets. Once the crop has two cotyledons or after 10 days, it rarely needs any further protection against these pests.

Robust demand for the crop

Sunflowers are a low-input crop, with seed being the most expensive component. Growers can use a stale seedbed to control all weeds, including black-grass. Pre-emergence pendimethalin should be used, and then on weedy fields, a post-emergence application of Emerger (aclonifen) can be used for broadleaved weeds, and Centurian Max (clethodim) for grass weeds can be used under an EAMU at growers’ risk. On most fields any weeds that germinate after crop emergence normally die as the crop closes in and prevents sunlight from getting through.

Fertiliser needs are low and are often zero on fertile sites, as the crops’ requirements are only 50N:80P:150K. Soils of Index 2 or more require no bagged fertiliser other than a little seedbed. Sunflowers are susceptible to boron deficiency, which can lead to infertility, especially on calcareous or sandy soils. Where deficiency is, 450 g of boron/ha can be applied as a foliar spray at bud formation.

Average yields in the UK are between 1.6 t/ha and 3 t/ha, with the best results being achieved usually in hot, dry years. Potentially, sunflowers could reach a yield of 4t/ha and United Oilseeds achieved 7t/ha in trials. A variety such as Bella reaches a height of 150cm and it has good standing power.

The flower head should be around 10cm across, and the canopy closes over to shut out sunlight. Sunflowers attract pollinators and small birds, so are very good for biodiversity on the farm.

Crop is desiccated when seeds are between 15 and 30% moisture. The stem should be fully dead and no longer green or yellow. Harvest occurs, using a normal cereal combine with minor adjustments, normally at the end of September.

This means farmers can drill winter wheat as a following crop. Seed dries fast and can be dried on an air-drying floor down to 15% moisture before drying with warm air down to 9% moisture.

At harvest, the back of the seed head may be infected with Botrytis or Sclerotinia if conditions are mild and wet. By growing an early variety such as Bella, harvest can take place before these diseases are problematic.

Back in 2024, United Oilseeds launched the first buying pool for sunflower seeds in the UK for growers with drying facilities on the farm and who are growing 10ha or more to allow full lorry loads to be delivered to the end markets.

This provided growers with a known market without having to develop local markets for birdseed. The UK imports 60,000 tonnes of sunflower seed for the birdfeed market yet produces only 15,000 tonnes, the expert said.

There is a robust demand for the crop. The contract specification includes no more than 4% broken kernels, no more than 9% moisture and no more than 2% admixture. United Oilseeds have experience in trading sunflowers and see this crop as a viable spring alternative. The crop is also eligible for SFI at £45/ha.”

Mr Groom concluded: “Bella is an early-maturing, high-yielding sunflower variety performing consistently well in trials and commercially in England. It is an early variety with a high oil content of 48-50%.

“It has good standing ability, which reduces neck snapping, as well as high dry matter yield and excellent disease resistance, and has been bred specifically for the UK conditions. There is an upward trend in demand, and sunflowers provide a great break crop as well as brightening up the agricultural landscape.”

Quick guide to growing sunflowers

• Historically, sunflowers can be successfully produced south of a line from the Wash to the Bristol Channel, but this area has now expanded northwards as average temperatures increase.

• Grown on any soil type. Optimum pH is 6.5 to 7.5.

• Drilled at a depth of 3 to 5cm from the 10th of April onwards depending on frost and wet conditions but with a consistent 7° C soil temperature.

• Sunflowers are sown at 110,000 seeds/hectare to achieve a population of 100,000 plants/ha on a 25-45cm row width.

• Sunflowers should not be grown on a rotation closer than one in four years to prevent disease (such as Sclerotinia) buildup in the soil. Do not follow sunflowers with potatoes.

• Sunflowers are a low-input crop. Being drilled in April allows weeds such as black grass to be controlled by a stale seedbed with glyphosate. A pre-emergent herbicide containing pendimethalin (Stomp) is used for early weed control, but later in the season if weeds germinate, they then die as the crop closes in and prevents sunlight from getting through.

• Average yields in the UK are between 1.6 and 2.5t/ha with the best results usually in hot, dry years.

• A variety such as Bella reaches a height of 150cm and has good standing power. The flower head should be around 10cm across, and the canopy should close over to shut out sunlight.

• Harvest occurs from mid-September onwards using a normal cereal combine with some minor adjustments.

• Sunflower seeds dry out fast and can be dried on an air-drying floor down to 15% moisture before drying with warm air down to 9% moisture.

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