Ideally to plant winter wheat you should have a seedbed that is near 80 per cent of field capacity (the maximum amount of water your soil can hold).
If your seedbed is dry prior to seeding, a light irrigation of 15 mm should be applied.
During the vegetative growth stages, water should not be depleted to less than 50 per cent in the upper 50 cm of the 100-cm root zone. Irrigation during this stage should start when the available soil water is near 60 per cent to prevent it from getting below 50 per cent.
At the beginning of the late boot/early heading and flowering stages, irrigations should be scheduled to fill the entire root zone at 100 cm to field capacity.
Adequate soil water for winter wheat is most important in the flowering growth stage. During this period the root zone should be increased from 50 cm to 100 cm and soil water should not go below 60 per cent of available.
Once the crop has reached maturity and the colour has turned from green to brown, the crop will no longer need irrigation water.