When should I stop irrigating wheat before harvest?

Give the last irrigation at the dough stage, roughly 110 to 120 days after sowing, then stop. After that the crop needs to dry down for harvest. Do not irrigate once the grain has hardened, as late water keeps the field soft, encourages lodging and delays harvesting. Harvest when the grain is hard, the straw turns golden yellow and grain moisture is around 12 to 14 percent. If you bite a grain and it cracks crisply rather than denting, it is ready. Stopping irrigation at the right time also helps the combine move easily and reduces grain spoilage.