Timely operations are key to maximising farm profit and sowing is one of the most time-critical operations. This is because of the yield penalty associated with delayed sowing in most regions. The yield penalty from delayed sowing is due to only a short period in spring (approximately 10 days) during which crops can flower to maximise yields. This is referred to as the ‘optimal flowering period’ and its timing and length varies with location and climate.

During the optimal flowering period, the combined yield loss from drought, heat, frost and insufficient radiation are, on average, minimised and hence yields are maximised in the long term.

In any individual year, these abiotic stresses can still damage crops even when the crop flowers during the optimal period. Achieving optimal flowering can make a big difference to yield and profit and costs very little to achieve. However, there are some challenges with sowing wheat early.