"... The number of grains is ‘decided’ when wheat is at the fourth leaf stage, in February, even when the ear cannot be identified by eye. This is closely correlated to the amount of light the plant absorbs. To increase the number of grains in the ear we should spray Pro Light in February, before the tillering. In biodynamics it is recommended to do spray 501 three times, while if we use Pro Light only a single treatment in early February is suggested. In that moment we determine the number of kernels, then the plant will fill them with the light that it will absorb in the post-flowering period. If after flowering, the sky is overcast and the plant does not absorb the necessary light, the ear remains empty at the apex or at the base, depending on whether the last rain fell in the Full Moon (governing an excess) or in the New Moon..."