(1) Using var. William Pitt, we investigated the growth of tops, the number of vegetation-points and development of bulbs in each six stage of growing period under the different soil condition of suitable humidity, dryness and excessive humidity.
(2) Dryness had conspicuously bad influence at the beginning and active stage of development of the vegetation-point, whereas, dryness at the beginning stage of planting up to the leaf developing, as a whole, had little effect on growth and yield.
(3) Harm of excessive humidity appeared at the late stage of planting, and on the contrary, at the beginning stage up to the leaf developing both growth and yield were rather bettered under this condition.
(4) Both dryness and excessive humidity in any stage of growing period gave little effect on the numder of vegetative-points.