The invention discloses a method for promoting
plant growth by illumination, in particular to designing a
light source product with universal meaning according to the spectrum demanded by
plant growth, therefore the method of supplementary illumination of plants in raising
seedling of plastic tents and factories is found. The method comprises the following processes: (1)
seedling preparation; (2) confirming the absorption spectrum of the plants; (3) testing the
photosynthesis under different light qualities; (4) comparing and analyzing the experiments so as to confirm the light absorption of different plants; (5) designing
light source equipment; (6) supplementary illumination is carried out to the plants. In the method, spectrum
test equipment is used for testing the plants with different types; the light sources with different wavelengths are chosen and made according to the absorption spectrum of the plants, therefore the pertinence and efficiency of the
light source can be improved efficiently. The
bud ratio and the
survival ratio can also be improved efficiently, the
seedling state can be shortened, the
biomass of seedlings can be increased, and the height of the seedlings and the number of leaves are promoted for increasing, thus shortening the growth period of the plants efficiently and improving the efficiency and benefit during raising seedling and growth.