On the previous page I mentioned the importance of air to a plant. For us, human beings, the importance of light to plants is even more obvious, so let's have a light discussion about light.
Most of us will start growing Haze with clones or cuttings, as it is hard if not impossible to get seeds.
The starting plant, be it a clone or a seedling, doesn't need very much light to start with. You could very well use fluorescent tubes (color 33, or cool white). If you would mount them 15 cm. (6 Inch) apart you would have sufficient light to start up clones or seedlings. Keeping them 7 cm (3 in) above the fresh cuttings would be a nice start.
Because the little amount of heat produced by these lamps, there's no real problem should the clone touch the lamp later on, once it starts growing.
For flowering marihuana, fluorescent lights are not bright enough, and are of the wrong color.
Actually, with light it's the same story as with air. That is, you want as much as possible. And this is where High-Intensity Discharge (HID) lamps come in. At the moment there are two kinds of HID lamps suitable to grow plants indoors.
I already explained that the white light we see from the sun,
actually is a mixture of all colors.
At this moment, it's technically very difficult, if not impossible, to copy sunlight. It's a lot easier and cheaper to fabricate bulbs that produce only light in one color or portion of the spectrum, the so-called monochromatic light. Sometimes these monochromatic (Low Pressure Sodium) bulbs are used to enlighten highways, streets, and parking lots. And because of the fact that they only produce this one color (yellowish-orange) they are absolutely inadequate for our goal, namely to force weed into bloom.
You absolutely need the agricultural HPS bulbs and the appropriate lighting device to flower
weed because these bulbs will also produce light in the blue area of the spectrum.
All of the bulbs mentioned above, including fluorescent tubes, require special "ballast's" to start up. These ballasts are not interchangeable, so please don't experiment with using the bulbs in the 'wrong' device. Even if your HPS bulb would 'work' in a MH device, you're literally playing with fire. Besides this fire risk, your bulb would probably not produce as much light as it could when mated with the appropriate ballast.
Metal Halide and HPS bulbs need time to heat up before they achieve maximum output. Besides that, once turned off, they need to cool down before they can be started up again.
As we all know ;-) following the inverse-square law,
the amount of light that falls on a given area weakens to one-fourth if you double the distance.
Because Haze tends to grow big, this is something to take into account. The amount of light produced by even the strongest HPS lamps hardly meets the plant's needs, this means the lower parts of your plants don't get as much light as they should. The only advice I can give here is to make sure that every wall inside your growing-room is painted white, preferably with old-fashioned chalk-paint. Because of its rough structure, chalk gives the best reflection. It's also more diffuse than the reflection of other materials, such as plastic, and plants seem to benefit from it.
Still, it's always a good idea to keep your lamps at the closest distance possible.
If you use 'deep-beam reflectors', which are perfect for our goals, this distance is about 40 cm (15 in.). With the so-called 'wide reflectors' you could even lower the lamp some more.
As a rule of thumb, I can say that you have to watch the leaves closest to the bulb. If they start curling, you need to increase the distance between bulb and plant.
Although a wide range of outputs are available, I prefer 400 Watt HPS lamps for flowering.
I would only use 600-Watt lamps to grow a relatively big yield on a small area, like a closet.
The heat generated by these lamps can be significant. In spite of this, I think two 400-Watt lamps are a better choice than one 600-Watt lamp.
So, if you are 'just starting up' but plan on maybe grow bigger, buy 400-Watt lamps; they are a better investment for your future.
Hang them about one meter (3 feet), apart and use pulley blocks so you can change the height according to the growth of your plants. More lamps usually give better results because the light-beams overlap each other. Especially plants in the middle feel at their best, because the light is coming from all directions.
Because of the high currents required by the lamps,
it's best to pay special attention on the way you connect them.
The safest thing to do is to wire them separately on their own circuit.
What we also need is a good quality timer to switch the lamps on and off.
Again here lies a problem. When starting up the lamps, the ballast will draw about 30% more electricity than during its normal burning hours. This will cause a spark that will destroy the switch in the timer. The switch will 'hang' so your lamps won't go off, causing disaster for your plants because all of a sudden they get 24 hours of light per day.
Besides that it could start a fire, so never directly connect your lamps to a timer-clock.
What you need is a relay; this device is specially constructed to safely conduct the high currents involved. Because the timer is only used to steer the relay, which only takes a bit of electricity, this is the one and only safe way to turn on your light!
Again I want to emphasize the importance of your room being completely sealed of from other sources of light.
A lot of harvests already are gone to smithereens because of someone being too curious, and snooping in during the dark period.
Remember, even the smallest amount of light during the night will cause your plants to delay blooming. Too much light during the night could even prevent blooming at all, keeping the plant in its vegetative lifecycle.
Make very sure no light leaks in, especially from outside.
The best way to achieve this task is to wait for a sunny day, (first ;-) roll a joint and than sit in the room for about ten minutes with the lights off. If after this time you still don't see any trace of light, you can be reasonably sure it is dark enough for your plants.
Pay special attention to the labyrinths, windows, doors, etc.
Even after this thorough inside inspection, it would be a good idea to check the outside of the room as well. This inspection round is best carried out at night, with all the lamps inside burning.
Again pay special attention to windows and other openings.