To start you need a small space - a closet roughly 60x150x200 cm (that's 2x5x6 ft for the archaic).  Cover the walls, ceiling and doors with aluminized mylar (if you can find it) or aluminum foil, shiny side out.  This saves light for the plants, ideally, the only light absorber in the room is plant.  (Mirror tiles are an option for the really rich). Actually, flat white paint works almost as well as these high-tech methods.  Use something cheap: put your money into things like lights that are really important. The next step is to put lights in the room.  Fluorescents are the cheapest and most readily available. Not to mention the coolest.  This is the real advantage of fluorescents for the closet grower.  For the professional, expensive metal halide and high-pressure sodium lights give more light for less electricity.  But these lights are overkill, and too damn hot, for the amateur closet grower. Water the plants twice a day during this time [vegetative growth].  About 12 hours apart is best but a few hours either way is ok.  Feed the plants once a week with a 15-10-10 plant food or a standard "Miracle-gro" product from any local discount store.  Again, to do better, get a book. You probably don't need to water quite this often, and you can probably get away with feeding more often than once a week.  I water once a day or once every other day, feeding with every or every other watering.  The key is to use a high-nitrogen plant food during vegetative growth, and a low-nitrogen plant food during flowering. when the plants are about 60 cm (2 ft) high you can go into the flowering stage.  To do this set a timer for 12 hours of light and 12 of dark.  If you've left the door open for ventilation, close it during the dark period.  The darker the plants are the better.  After a few weeks the plants will begin to differentiate.  The males produce "balls" with pollen and the females produce feelers at nodal points (stems and branches). The plants will stop lengthening almost entirely shortly after you shorten the light cycle (within a week or two), so my advice is not to cut the lights until the plants are just about as tall as you want them to get.  It's hard for the beginner to tell male and female pre-flowers apart at first.  The "feelers" discussed above look like two tiny white hairs. Note that things should be dark through the entire dark cycle.  Turning on the lights even for a moment can prove to be too much of an interruption.  (I don't know this from personal experience, but I've seen in repeated in enough books/articles on the subject to consider it good advice). For the best sinsemilla you want to cut out the males before they release pollen.  If you want more seeds this is not necessary. Most of the time, marijuana separates into male plants and female plants.  Sometimes, though, you end up with hermaphrodites.  Most growers seem to have an antagonistic relationship with hermaphrodites, but not me.  I think they're wonderful.  Here's why.  When I have a hermaphrodite female, and it pollenates itself, all of the seeds from that pollenation are guaranteed to be female.  A batch of female seeds is the best thing you can ask for as a grower. The entire cycle takes about 4 months.  Usually 4 to 6 weeks in vegetative stage, 2 weeks to differentiate and another 8 weeks to flower.  Harvest when the large sun leaves begin to yellow and drop off. Vegetative growth will be longer if you grow your plants larger than two feet tall.  The large sun leaves may start to yellow and drop off even before you start to flower the plant, so this isn't the best indication.  When the hairs on the female plants are mostly dried up (with wet white or red hairs distinctly in the minority) it's about time to harvest.  You don't want to harvest too early, or you'll miss out on the most flower growth and most THC production. But enough of this... Go buy a book.  "Marijuana Growers Insiders Guide" is very good, and available from many mail- order outlets (see High Times) and even bookstores.