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Originally posted by sublimstri on the Shroomery, great resource for lighting information
POOR LIGHTING SYSTEMS
Domestic Lights: Figure 5.6 - A domestic bulb. Also called an incandescent light source. These are the lights you find in use around your house. These lights come in all sizes and wattage - 30 watts to 150 watt. These lights are not suitable for growing because of their low light intensity and bad colour spectrum. 151 _________________________________________________________________________________________ AVERAGE LIGHTING SYSTEMS
Fluorescent Tube Lights: Figure 5.7 and 5.8 - These are examples of some fluro fixtures and bulbs that can be bought in most hardware stores. 152 _________________________________________________________________________________________ These lights are the long industrial lights that are found in many a school and work place. These lights come in nearly all lengths and sizes. 2 to 10 feet are the main sizes that are out there. They also run between 10 watts and 300 watts. These lights are okay for growing but they provide little light and are hard to set up properly. They also are not in best light spectrum for Cannabis plants to grow in.
Halogen Lights: Figure 5.9 - A Halogen light. 153 _________________________________________________________________________________________ Halogen lights are the small lights that can be seen on the outside of factories for flood lighting the grounds during the night. They are usually small and black. These lights can range anywhere between 75watts and 4000watts. Halogens get extremely hot and can provide an unsuitable condition for growing Cannabis under. They are not recommended because they are dangerous to use indoors for growing. They are also not in the best light spectrum for growing Cannabis.
Fluorescent White Tube Lights: These are not in use much and are very similar to the Fluorescent lights except they are in the correct growing spectrum. These lights are not very strong and do not range much above 200watts. They are only recommend for growers who do not want to grow full flowering cannabis plants. 154 _________________________________________________________________________________________ Figure 5.10 - White Tube Light. BEST LIGHTING SYSTEMS Horticultural Lights: These lights are professional horticultural lights. They are developed by horticultural lighting companies and are tested to suit growing plants indoors. These lights are commonly called HID (High Intensity Discharge). Like the former lights these also come in kits with bulb, reflector, ballast and timer. They also come in different wattage and different shapes and sizes. If you want to grow good bud then you need a HID. A HID is the second most important purchase you will make next to choosing your strain. 155 _________________________________________________________________________________________ Metal Halide (MH) and Mercury Vapour (MV): The lights are HID lights and are used for the seedling and vegetative growth stages of your plant. They can also be used for flowering and are quite good too. They come in all shapes and sizes and range from 75W - 4000watts. These lights are very common and are a good kit for the indoor Cannabis grower. Mercury Vapour is not as common as it used to be. It has almost been replaced by Metal Halide now. If you have a choice between the two it is best to stay with the new MH kits. MV also has a tendency to be slightly out of the optimal spectrum range. High Pressure Sodium (HPS): This is the lighting choice of many a Cannabis Cultivator. These lights come in all shapes and sizes and have a range of 75watts - 4000watts. These lights are in the perfect spectrum for growing cannabis and come highly recommended. 156 _________________________________________________________________________________________ Figure 5.11 - This is an example of a HPS and also a MH Light system. There is nothing at face value to indicate that the light is a HPS or a MH. To check this out we need to look at the ballast and the bulb and read what is says about the type of light system that it is. MH lights tend to give off a blue tone, while HPS tend to give off an orange tone. WHAT TO LOOK FOR WHEN BUYING A LIGHT. The first thing to say is that some growers have a MH set-up for seedlings and vegetative growth and a HPS for flowering. The HPS is a better flowering lamp, while the MH is a better veg lamp. If we can only afford one we should get a HPS. Both MH and HPS can be used for vegetative growth and flowering. However since we are growing for bud, we should try to get the best HPS we can. The next thing they look for is the light kit itself. Check to see that the light is 157 _________________________________________________________________________________________ certified and is in good shape. Then check to see if the light is air-cooled. Some of these lights have a fan built in which keeps the light cool. If you see this then you know that you are going to need somewhere to vent your air. This may mean that you need to adjust a wall in your grow area so that the air is extracted from the light. Figure 5.12 - This picture shows two air-cooled hoods attached to their respective air ducts. This photograph is by Chimera. 158 _________________________________________________________________________________________ Lights that are air-cooled (Figure 5.12) tend to last longer and do not heat up your grow area that much. Most expert growers like to keep a room at a stable controllable temperature and use these air-cooled lights to achieve that. If your light is not air-cooled then you will have to build an air vent and fan in your grow room wall to keep the temperatures under control. Cannabis leaves will burn if placed too close to a HID light. Figure 5.13 - This is a water-cooled light system. These inventions have been around for awhile but have not caught on that much because they require a good bit of work. A constant pump of cool water must be circulated into and out of the light system. 159 _________________________________________________________________________________________ The next thing to check is how the light is supported. Does it require a light stand or does it require to be hung from the ceiling. In most cases you will be able to make your own stand if you feel that you are not willing to fasten a few hooks and chains to your ceiling. Also check to see if the electrical fittings suit your needs. Will they plug straight into your system at home or do you need an adapter? Maybe you might require an extension cord with your purchase. Most HID kits can only take a specific wattage of bulb and a certain type of bulb. If you have a 600W HPS system, then you should only use 600W HPS bulbs. Some lighting kits have something called a 'switchable ballast' (Figure 5.14). This means that you use both MH and HPS lights with the system. Check your kit for further details. 160 _________________________________________________________________________________________ Figure 5.14 - This is a picture of what the switch looks like on a ballast that can take 2 HID types. The next thing to look for is the guarantee. Check to see what the manufacturer has said about this light and how long the guarantee is for. Last but not least is the most important part of your light. The wattage and lumens. WATTAGE AND LUMENS HID Lights can range anywhere between 75W and 4000W. In general the stronger the wattage the more light that bulb will produce. However we must also consider another factor and that factor is called Lumens. Lumens are the correct way of measuring how much light per square foot a bulb emits. Lumens and wattage do go hand in hand but can vary a large amount between 161 _________________________________________________________________________________________ systems. The better the lighting kit, the better the lumens it will cast. Lumens have more to do with the design of the light than the wattage of the light itself. Some 600W lights may give the same lumens as a 400W light. Have a look at this chart: This is interesting because we have two types of HPS lights using the same bulb wattage and one of the types is casting more Lumens than the other. The reason for this is that the higher lumens kit is better quality than the other. So we now know that some lighting kits produce better Lumens than others. Check through HID lighting kits and look at how many lumens they cast. This is a good indicator of how professional that light is. Also a 4000W HID is too much for one single plant. A 1K bulb is the maximum limit per light you should use. Use several 1K bulbs if you need more light. A 4K bulb will bleach Cannabis and is very hot. LAMP TYPE WATTS LUMENS M.V 175 8000 M.H 400 36000 H.P.S 600 45000 H.P.S 600 36000 162 _________________________________________________________________________________________ LUMENS AND MARIJUANA GROWING Now for the big question. How many Lumens do I need? Well this depends on three things. (1) How much do you want to spend? (2) How many plants do you have? (3) How big is your grow area. You do not want to go less than 2500 Lumens, even for one plant. You want to get the best so you need to hit the 45000 mark or more. In general one light that casts 45000 lumens is enough to cover a workspace of about 3 feet by 3 feet. This is quite an average space and you will probably get anything between 6 - 9 plants in that area. Again we must keep in mind the strain that we are growing. One large sativa plant can cover a 9 square foot grow area in no time. Short indica plants are different. You can get maybe 12 plants into a 9 square foot grow area. If you really want to pump up your plants then you may consider a lamp that casts 100,000 Lumens or more. If you want a bigger grow area then you may consider 2 lamps that cast 100,000 Lumens each. All is relative to how much you want to grow and the size of your grow room. Let’s say for the record that we would like 163 _________________________________________________________________________________________ to grow 4 plants. Then what we should aim for is a light that casts 45000 Lumens. This means we should buy a 600-Watt HID system. Let’s say we want to pump up our available light to around 60,000 Lumens. This means we should buy a 1000-Watt HID system. If our area is bigger we might need 2 or more 1000-watt HID lights to achieve this. It all very respective to the 3 elements we mentioned above. There is nothing wrong if you want to use a 1000-watt HID light on 2 plants. They will grow bigger and better. The only thing is, do we really want to spend all that money on the light and the electricity bill? HID lights range anywhere between $220/£200 and $700/£670 for a full kit. You may be able to buy the parts and build your own, but this is only recommended if you have some experience with lights first. A 600W HPS kit should cost about $250/£230. This is money well spent if you want great plants with big buds. Over time you will understand more about grow rooms and how to light them properly. With experience you should be able to tell what light suits your needs. As a general rule, when in doubt buy a 400W HPS or better.
I'm not quite sure how I stumbled upon this thread but I think it's worth mentioning that this was taken directly out of the Cannabis Grow Bible by Greg Green. It's a worthwhile read if you're new to growing and looking to learn something.
-------------------- There can be only none!
"Prohibition...goes beyond the bounds of reason in that it attempts to control a man's appetite by legislation and makes a crime out of things that are not crimes. A prohibition law strikes a blow at the very principles upon which our government was founded."
-- Abraham Lincoln, December, 1840