sexing

how long does it take/about how big do the plants have to get before you can tell if they are male or female. i have a small closet so i only planned to grow 1 maybe 2 plants but don't want to waste time growing two males. all help and advice is much appreciated.

As I understand from reading on this site..
Some plants will show preflowers after about 4 weeks from sprouting while in the vegetative stage....
Or they will show their gender soon enough into the flowering stage.. you can also use a paper bag method to put a part of the plant into flowering to see the sex.. instructions for that are here:
https://www.rollitup.org/view.php?pg=faq&cmd=article&id=99

Hope that helps at all

helps alot thanks

rarely you will see the sex during veg, usually not after 4 weeks though... after you switch lights to 12/12 sex will show in about 2 weeks or so. check everyday for males and kill any asap.