30 days is awful young for flowering, 30 days with a clone is ok cause in actuality it is as mature as it's parent but a 30 day seedling really isn't mature enough. here is an exerpt from a paper entitled 'Marijuana Botany' by Robert Connell Clarke and i quote:

"The maturation of Cannabis is normally annual and its timing is influenced by the age of the plant, changes in photoperiod, and other environmental conditions. When a plant reaches an adequate age for flowering (about two months) and the nights lengthen following the summer solstice (June 21-22), flowering begins. This is the triggering of the reproductive phase of the life cycle which is followed by senescence and eventual death. The leaves of Cannabis plants form fewer leaflets during flowering until the floral clusters are formed of trileaflet and mono-leaflet leaves. This is a reversal of the heteroblastic (variously shaped) trend of increased leaflet number through the pre-floral stage.
The staminate and pistillate sexes of the same strain mature at different rates. Staminate plants are usually the first to begin flowering and releasing pollen. In fact, much pollen is released when the pistillate plants show only a few pairs of primordial flowers. It would seem more effective for the staminate plant to release pollen when the pistillate plants are in heavy flower to ensure good seed production. Upon deeper investigation, however, it becomes obvious that early pollination is advantageous to survival. Pollinations that take place early form seeds that ripen in the warm days of summer when the pistillate plant is healthy and there is less chance of frost damage or predation by herbivores. If conditions are favorable, the staminate plant will continue to produce pollen for some time and will also fertilize many new pistillate flowers as they appear. After a month or more of shedding pollen the staminate plants enter senescence. This period is marked by the yellowing and dropping of the foliage leaves, followed by diminished flower and pollen production. Eventually, all the leaves drop, and the spent, lifeless stamens hang in the breeze until fungi and bacteria return them to the soil."