You have 4 main concerns when growing indoors. The room, the air, the nutrients/water, and the lights (der).
THE ROOM: How big is your grow room, in this case your closet? An average plant indoors could be about 3 or 4 feet tall and about 2 feet diameter around. Do you have that kind of space in your closet? This can be altered with training the plant (LST, SOG, SCRoG, etc). Take in count the size of the pots you grow in, and the size of the lights. Maybe a 5 foot tall closet would sound good at first, but take in account the lights and the pot, your looking at around 3 or 3.5 feet of room, not as easy without LST.
THE AIR: You NEED NEED NEED NEED good air circulation in your room! ITS A MUST!!!! Trust me. You need a fan pulling air in, a fan pulling air out, and a fan moving air itself around the room. Choose fans by space of your room. Fans are rated by CFM or cubic feet per minute. You want a fan moving enough air to have completely fresh air every 3 to 5 minutes. So a 4x4x8 foot room has 108 square feet of air, a fan that moves about 30 to 40 CFM would be about good. Take note that air moving in should be the same as air moving out, so if your exhaust fan moves 45 CFM, your intake fan should move 45 CFM. Otherwise you have weird negative pressure no one wants to talk about. Also, an internal fan (oscillating is ideal) is a MUST! I speak from expirience, without one, you are shooting yourself in the foot bro. The internal fan promotes strong stems, making flowering easier. A wimpy stemmed plant will droop and sag, and by flowering youll need something to hold it up for sure or itll collapse on itself.
NUTES/WATER: Nutes are a touchy subject for everyone has their own opinions on whats the best. There are 3 main stages of plant life for marijuana: seedling, vegetative, and flowering. Seedling stage, nutes arent needed. Vegetative, youll want a nutrient with an N-P-K (abalance of nitrogen, phosphorous, and potassium) of about 10-5-5 (20-10-10 is the same balance, its just proportions). This is ideal because the plants use nitrogen to grow big and tall. For flowering, youll want a fertilizer with an N-P-K of about 5-10-10. This is because plants use the phosphorous and potassium to grow big buds.
For seedling stage, water only to keep soil moist until they sprout. After that, water only when the plant needs it (it gets a little limp and soil is completely dry). This forces the roots to stretch to get all available water, meaning bigger and faster growth.
THE LIGHTS: This is one feild where there are many options. CFLs, HIDs, HPS, the list goes on. Whatever you think will be easiest will work (except LEDs... dont use that shit). I recommend CFLs for beginning growers as they need no special wiring and screw into normal light sockets. What you are looking for to grow plants is the amount of Lumens per square foot (call it l/sq.f). You need AT LEAST 3000 l/sq.f to grow effectively. The sun gives off about 10,000 l/sq.f. On average, indoors you want about 6,000 to 7,000 l/sq.f. CFLs are pretty efficient in lumens per watt emitted, about 65 lumens/watt. HPS are about 100 lumens/watt. Flourescents are lower, somewhere around 30 lumens/watt I believe.
Through out the life cycle, you should keep CFLs about 1 to 6 inches away from the plant top. HPS lights are more like 1 foot away. This keeps the plant shorter and bushier. If your lights are too far away, your plant will become leggy and stretchy. Stretchy plants are weak, and produce fluffier bud.
I hope this answers alot of questions, if you have more, Ask Away! We are here to help!
MVNugs
