first time grower I'm using a 100 hps floodlight. have five plants and just started flowering a month ago. 3 out of five have some nice flowers all over them but there is no sign of any flowers or sex on the tother two, I've been on 12/12 for over a month.
first off you need more light..100 watts of HPS is good for only about 1 plant...next time you grow that many try and get at least a 400 watt light..as for the plants not showing sex..iv'e had that happen a few times..i grow from bag seed due to the fact that i have a shitload of it and i save and label it when i get it so i know whats good and whats just ok...my freinds keep me supplied..as for those plants not showing sex..after a month i wouldn't waste my time on them..if they aren't showing by now excludeing that they aren't stressed in any way ,light leaks of abnormal light interuptions etc....good luck