A few basic stuff 

A few basic stuff

Soil Mixture

When selecting a soil make sure it is dark and rich. Spring for the expensive stuff, it will pay off. Mix about 2/3 potting soil and 1/3 vermiculite or perlite. Worm castings or other manure's may be added but are not necessary.

Lighting

Lighting is the key factor to growing Marijuana. Without light the plants will die. Find your local hydroponics store and travel there. Upon arrival you should already know how big your growspace is in square feet. A good light measurement for light would be 30-50 watts per square foot. The more the better. You can choose from one of two different types of light. Metal Halide (MH) or High Pressure Sodium (HPS). Metal Halide has a good spectrum for growing and causes the plant to have short internodes between leaves. HPS has a more orange spectrum and also performs well showing better results in the harvest stage. It's really a matter of personal preference. My lights are convertible from both MH to HPS. Metal Halide for the vegetative stage and High Pressure Sodium for flowering. While you're at the hydroponics store buy some spare bulbs and a timer. (digital is best)

During the vegetative stage set the timer for 18 hours on and 6 hours off. This lighting schedule will allow the plants to grow first before you begin flowering. During the flowering stage set the timer to 12 hours on and 12 hours off. This will result in flowering.

Watering

Watering if done incorrectly can be devastating to a plants life. Too little water and your plant will begin to wilt. Too much water and the roots will begin to rot. When the roots rot you have no way of knowing. The only way you know is when the growth of your plant stops. This is hard to determine and usually takes a week or two to figure out. Write down the measurement of your plants weekly so you can keep track.

Water whenever the soil on top feels dry to the touch. If it is damp postpone watering till it is dry. Water until the soil is moist and repeat this process every watering. To be absolutely sure you don't over water goto your local garden center and buy a moisture meter. The meter should read 3 when water is needed and 6-7 when you have watered. Different moisture meters will have different gauges. Figure out what is best. It is not necessary to have a meter you will get used to watering properly after a while.

Adjusting pH

Adjusting pH properly will give you a better outcome when harvesting your plants. They will be more healthy and thus more potent. pH is a meter used to judge akaline or acidity of the soil. Marijuana can grow at a wide range of pH levels but it is optimal to have it range at 5.2-7.0. To check and adjust the pH you will need to buy a pH test meter and a bottle of pH up and pH down which can be found at local nursery or hydroponics store. Every watering you will want to adjust the pH of your water to your desired level. I set my water to 6.0 because I find it to be optimal for my plants growth. You will also want to check the soil pH, if it is not optimal adjust your water accordingly. Your pH can fluctuate during the grow and it will not do allot of damage to your plants but don't let it get out of hand.

Example: Soil pH is 6.8, you want it to be 6.0 set the water at 5.2 and it should bring it to the desired level.

Experiment with your pH, different strains of weed will do better under different conditions.