Wheatgrass jointing stage is optimum growth period

The effect of stage of growth on the chemistry of the grasses.

Kohler G. J. Biol. Chem. 1944. 152:215-223

Younger grass tends to be richer in protein, soluble carbohydrates, carotene, vitamin C, thiamine and riboflavin. Using oats, Kohler found that several of the vitamins, protein, crude fat and chlorophyll reached peak concentrations at or near the jointing stage, hence the nutritive value of grass is likely to be optimal at this point