Dr. Dave Hooker from U of Guelph provided me with this excellent slide showing the growth stages of wheat where yield is built. These are the areas we most focus on supplying the plants with the right nutrition. I've combined it with Stoller USA's nutrient and plant hormone cycle that shows which nutrients and hormones are required the most at certain growth stages.

Adpated from Siafer and Rawson (1994) and Satorre and Siafer (1999)

Stoller plant nutrient and hormone uptake curve.