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As the wet weather continues, growers may be looking for spring cropping options with an extended drilling window to give heavy, clay-based soil conditions the chance to dry out and become more workable.

Like many crops, sunflowers do prefer well-draining soils, but growers may benefit from the extended drilling period.

Neil Groom, general manager at Grainseed, says: "You can drill sunflowers comfortably from April 10 until the end of May, so hopefully by then conditions will allow for a good seedbed."

Read more: Growers could look to sunflowers to boost crop options

IPM4 benefits

Sunflowers are commonly a low-input crop, with the largest expense related to purchasing the seed. The crop rarely requires much intervention, therefore providing growers with the opportunity to remain insecticide-free and benefit from the Sustainable Farming Incentive IPM4 (£45 per hectare for land managed without the use of insecticides).

Once the sunflowers have been harvested from mid-September to the first week of October, growers have the option to sell the crop through United Oilseeds' recently launched sunflower marketing pool, which has a price offering of between £350-£450/tonne.

Mr Groom says: "The other option is for growers to sell to a local farm shop as wild bird seed for the public to buy and feed birds in their back gardens.

"The trick is to weigh the seed into 5kg bags, as not many people will buy the 20kg bags."

Read more: Top tips to grow sunflowers as an alternative spring crop

Sunflower production in brief

Grainseed's sunflower expert Edward Stanford gives his six top tips for sunflower production.

1)    Where to grow sunflowers

Sunflowers can be grown on any soil type, with an optimum pH of 6.5 to 7.5. They often grow well on potash rich clay and clay loam soils in open, sunny sites.

2)    When should they be drilled?

Sunflowers should be drilled at a depth of 3-5cm from April 10 onwards, depending on weather conditions. Growers should wait for consistent 7degC soil temperatures to be the main driver for the drilling window.

Mr Stanford says: "Take time to drill properly. Sunflowers are sown at 110,000 seeds/ha 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 very important as it governs the seed head size, with yield coming from smaller heads."

3)    Rotation

Sunflowers should not be grown on a closer than one to four year rotation to prevent diseases, such as sclerotinia, building up in the soil. Mr Stanford advises growers not to follow sunflowers with potatoes, and that sunflower seed is treated with a fungicide to protect it from seedling damping off and blight.

4)    Inputs

Sunflowers are a low-input crop, with seed being the most expensive component. Drilling in April allows weeds such as black-grass to be controlled in a stale seedbed with glyphosate. A pre-emergent herbicide containing pendimethalin is used for early weed control. If weeds germinate later in the season, the weeds will often die naturally as the crop closes in and prevents them accessing sunlight.

Pests such as pigeons and slugs can be problematic, with pigeons only usually affecting the crop for the first 10 days post-drilling. Slugs create the most risk during the seedling stage. If slug numbers are high, Mr Stanford advises the use of slug pellets. However, once the crop reaches 10 days or has two cotyledons, it rarely needs any further protection against these pests. The fertiliser requirements of sunflowers are often low or zero.

5)    Growth

Average yields in the UK are between 1-2t/ha. A variety such as Grainseed's ES Bella reaches a height of 150cm and has good standing power. The flower head should be about 10cm across, and the canopy should close over to shut out sunlight. Sunflowers attract pollinators and small birds, so are good for increasing biodiversity on-farm.

6)    Harvesting

The crop is desiccated when the seed is between 15-30 per cent moisture. The stem should be fully dead and no longer green or yellow when harvest occurs; usually from mid-September to the first week of October.

Sunflowers can be harvested using a normal cereal combine with minor adjustments to the spiked combine reel to ensure they are collected in the intake auger rather than flicked back onto the field, says Mr Groom.

The harvest timing means growers can drill winter wheat as a following crop. Sunflower seeds dry out fast and can be dried on an air-drying floor down to 15 per cent moisture, before drying with warm air down to 9 per cent moisture.