i dunno if hermi seeds "pop" and then again all u will grow is hermi plants which i dunno why u would want, its ussually done by heat stress, the only thing stressing your plants with light will do is destroy your grow cycle, your plant is now flowering.. and to vegg it again will take atleast 2 weeks to convert back. And 3 weeks is to imature to flower. A timer is cheap and easy to find, and i think is abselutly neccessary, where did u find the info on light stressing to hermi a plant?