Sunflowers can make a very attractive addition to wide range of businesses. They can be sold alongside a range of other products, and due to the long flowering season this can even stretch into the autumn to coincide with pumpkins in the run up to Halloween. Heads can be cut as required and sold individual at till points for other crops. For sites where footfall is important – pick your own fruit for example – sunflowers can either be sold as a PYO product or grown as a backdrop for photographs. They can also be an easy route into cut flowers as a starter crop to build up a customer base. As well as a summer-grown field crop, sunflowers can benefit from growth under protection with tunnel grown flowers offering a longer season due to increased protection from wind and rain damage.
Sunflowers can be worked into a variety of schedules to suit different marketing models. Sunflowers planted at the end of April are likely to show flower formation in mid-July if conditions are favourable, or later into early August for larger headed varieties. Successive harvests of flowers can be achieved by new plantings every 7 – 14 days during the spring. Plants sown at the start of April will be ready for harvest in 14-17 weeks depending on cultivar and conditions, and will be ready for harvest between mid-August and early September.
Sunflowers are deep rooted, and will have significant water and nutrient needs although sunflowers can be grown in a wide range of soil types. However, sunflowers are unlikely to need much (if any) nitrogen) although micronutrients may need careful management, especially boron, as discussed below. They will grow best in a well-drained soil that will warm up rapidly in the spring. Sunflower can be drought tolerant, making them suitable for use on more drought-prone soils. For best results a south-facing field away from trees will be best suited to sunflower.
Sunflower is very susceptible to Sclerotinia which can be a risk to other crops grown in the same rotation, including potato and it is best to avoid short rotations of four years or less to reduce the risk. High soil nitrogen will also reduce yields, so avoid sowing sunflowers after crops that leave a large nitrogen residue such as brassicas. Weed control after establishment can be difficult due to few approved herbicides for sunflower, so an overwinter fallow period before planting can be useful in controlling grass and broadleaf weeds using non-selective herbicides.
Every effort is made to ensure the accuracy of information and recommendations given in these notes. All applications of crop protection chemicals should be made in accordance with label recommendations, which should be consulted before spraying. Some of the pesticides mentioned in these notes may not be supported by label recommendations for their use on crops but are permissible via Extension of Authorisation for Minor Use (EAMU) in the UK under ‘The Revised Long Term Arrangements For Extension Of Use (2002)’. In these cases, the use of the pesticide is at the risk of the user and Tyfu Cymru does not accept liability for any loss or damage caused by such use. The references to on-label approvals and EAMUs for use of pesticides in pumpkin crops and are correct at the time of writing. These are subject to change and approval may be withdrawn at any point. It is the grower's responsibility to check approvals before use of pesticides. If in doubt a grower should seek advice from a BASIS qualified advisor - this is available free of charge for eligible growers through the Tyfu Cymru program, please contact us to arrange an appointment – email/telephone advice is also available.