Sowing dates and Seed rates
Wheat
Winter wheat sowings can be very diverse, from September, though to January (latest safe sowing date). However, the optimal time would usually be from September through to October. Winter wheat varieties are bred and tested for the latest safe sowing date, and the majority can be as late as January or February. Now this might not be optimal, but it gives a large window for drilling. Most data for the NIAB recommended list is based on trials that were sown in October, ‘late sown’ is classed as after the 1st of November.
Early drilling of wheat can lead to problems later on in the growing season.
Black grass is a big issue for many farmers, and early drilling of wheat can exacerbate the problem with weed control. Dormant seeds can germinate while the crop is growing, leading to high levels of herbicide use (with some resistance seen) as well as a reduced yield, taking all in the crop and problems with harvest. A later drilling can also help with other weed problems, enabling better weed control.
Crops that are very forward come the spring can also be problematic, as they can be more prone to disease – leading to increased fungicide use.
Early drilled crops are more at risk from BYDV attack now that we no longer have seed dressings available to us. Insecticides give reliable control, but weather conditions need to be favourable in order for them to be applied at the right timing.
Some varieties are more suited to a later drilling, for example, Extase or Zyatt can be drilled later and still in their ‘optimal drilling time’.
Seed rates can vary depending on the time sown, and soil conditions. From 250ssm for early sowings, 350 for ‘normal’ and up to 400 for the later sowings.
Barley
For most conventional barleys, the sowing window is from early September through to early October, for those later drilling slots. Later drilled barleys can be more prone to disease. Typical sowing rates would be around 300 ssm, but this can be increase for the later sowings.
Oats
Offering the widest sowing window, from mid-September right through to November. For optimal drilling, it is usually between mid-September to mid-October. A typical sowing rate for oats would be between 300 to 350 ssm.
Seed rates are often influenced by drilling date and conditions – the later the drilling, or poor conditions, the higher the seed rate. Sowing rates on the later drilled crops are key, as a compensation for the reduced temperatures and tillering. Good disease resistance will also be an extra advantage when drilling late.
