Like good horticulturalists , they propagate strains of the plant that produce a high proportion of tetrahydrocannabinol ( thc , marijuana ' s active ingredient ) and speed their growth by means of heat and artificial light 他们像一个优秀的园艺家一样对大麻进行大量繁殖以能在大麻中大比例地获得四氢大麻醇( thc ,大麻的活性成分)同时他们还采用各种的升温和人工光照的方法来加快大麻的生长。