Details for Understanding Wheat Growth: How Do Wheat Heads Fill Up?

Wheat heads fill from the bottom up. The lower grains on the spike (closer to the base of the plant) typically begin filling before the upper ones (closer to the top of the plant). This is due to the sequential nature of the flowering process in wheat. The wheat head, or spike, typically flowers from the middle, then bottom, and finally the top, which means the bottom grains generally start filling first.