Although buildings and other structures may shade turf, trees are generally the most common source of shade reducing the amount of light available to the turf. Grasses, like all green plants, convert light energy into carbohydrates through a process known photosynthesis. These carbohydrates serve as the building blocks and energy source for plant growth and development.
In addition to reducing the total amount of light available, tree shade severely limits the amount of useful light reaching the turf. All wavelengths of light are not equally effective in photosynthesis. Green plants absorb primarily orange, red, and blue light while reflecting mainly green and yellow. Therefore, the majority of light reaching shaded turf is likely to be light, which has filtered through the tree canopy and is low in those wavelengths most valuable in photosynthesis and carbohydrate production.