Abstract: Method and apparatus for promoting by light irradiation the germination of seeds and the growth of plants generated by the seeds. The seeds to be treated are irradiated with radiation that is a simulation of the solar visible spectrum. The radiation may have a wavelength range from about 400 to about 700 nm. The irradiating light may be pulsed, for example at a frequency from about 10 to 150 pulses per minute, each pulses having a duration from 0.1 to 0.9 seconds and the intervals between pulses having a duration about from 0.1 to 6.0 seconds. The seeds may be cooled while irradiating them, such as to maintain the seeds at temperatures not exceeding 35° C. Cooling the seeds may be carried out by means of a stream of gas.