The Cannabis Connoisseur Handbook --- Coming Soon!!
Featuring concise tips with Dank links in addition to proprietary Nexus Style Cannascience.
Meanwhile check out these links about the essential oils in Cannabis, including Clove, Pine and Orange Oil:
::: Cannabinoid and Terpene Medical Properties :::
::: Terpenes and Terpenoids in Cannabis ::: 
::: Health Properties and Boiling Points of Cannabis Terpenes ::: 
::Beta Version Below::
::May Contain Major & Minor Errors::
How much light?
Having too much light for your grow space can severely inhibit yields and quality. Many growers seem tempted to push the wattage while trying to get a higher yield from their grow space however these attempts are repeatedly proven to be a waste of time and money.
Too many lumens causes problems.
There are a few reasons to use the ideal 'watts per square foot' for your room:
- Increased Yield
- Increased Potency
- Increased Essential Oils
- Less Equipment Cost
- Less Electricity Cost
--Simply put, too much light stunts growth and makes plants generally unhappy.
How many watts of light to use is quite easy to determine using Cannaversity's Grow Room Light Calculator. This will give you the ideal 'watts per square foot' to figure out how much wattage is needed for the dimensions of your room.
From here the easiest approach is take the total watts allowed for your room and find a reasonable amount of lights for the recommendation.
A recommendation of 2,050watts might be best suited for two 1000watt lights.
A recommendation of 1,400 watts max might be best suited with two 600watt lights. See Figure 2.1 below.
How far away from the plants do I place my light?
Each plant has an optimal range of acceptable lumens for every square foot of canopy space.
- The functional light intensity for Cannabis is: 5,000 - 10,000 lumens/sq.ft.
- The ideal light intensity for Cannabis is closer to 10,000 lumens/sq.ft.
Determining the ideal 'lumens per square foot' (aka Foot-Candles, roughly) for your specific setup can be trickier. Look at this post on THCTalk about Ideal Lighting Charts.
Using their "High-Pressure Sodium :: Foot-Candles Distance Table" on the very right you can see distance (in inches) your light needs to be to achieve 5,000 - 10,000 lumens/sf. The table features all sizes of HPS lights from 150-1000watt.
Now look at the second Chart titled "Approximate Penetration Range for Some Common HPS Lamps"
This chart shows at which height each light projects an ideal 9,000 lumens/sf footprint creating a dense exotic budtops. It also shows where diffuse light closer to 5,000 lumens/sf produces less then impressive nuggets.
For instance, if using a 600watt HPS light, the grower would want to keep the light 18 inches away from the plants to achieve the maximum light density of 9,000 lumens/sf. If the grower has parts of the plant 26 inches away from the light this will be the less dense "bottom nugs" given by the 5,000 lumens/sf intensity.
- 5,000 lumens/sq.ft. produces mediocre to above-average indoor cannabis.
- 10,000 lumens/sq.ft. produces exotic Connoisseur quality high-yielding indoor canopies.
In actuality, this is all a rough guide as each bulb & ballast & brand will have variation. How well your lights are cooled and your overall ambient room temperature will both have a major impact on your ability to bring lights closer to plants. Each strain and each phenotype will also have individual variation in its light intensity tolerance. Some modern indoor varieties can take quite a bit more then 10,000 lumens/sq.ft whereas some varieties can't take over 8,000-9,000 lumens/sq.ft.
- Never hesitate to experiment with light height adjustments to 'dial in' your strain and your room atmosphere
Cold air inlets and air-cooled glass-sealed light hoods become essential in growing optimized indoor cannabis.
- Find the ideal wattage for your room size using Cannaversity's Grow Room Light Calculator
- Divide total wattage between 2-4 lights
- Place lights evenly apart as depicted in Figure 2.1
- Keep lights above plant tops at the height that provides 9,000-10,000 lumens/sq.ft. as given by THCTalk's Ideal Lighting Charts
- Adjust height experimentally to 'dial in' individual strains, phenotypes and room conditions
Cannaversity has a great pictorial of the Various Hydroponic Types
Deep Water Culture (DWC)
Here is an example from Cannaversity of a Deep Water Culture (DWC) system with a Screen of Green (SCROG) built in.