[pipeman]

The best lights for growing are HID which is either Metal Halide (MH) or High Pressure Sodium (HPS). MH is the best for vegetative growth, and HPS is the best for flowering, but either can be used effectively for all growth stages. With HID's you need to have the right light distance from your plant to prevent burning it. HID's are commonly available at hydro shops.

 

It is a good idea to have a reflective light hood as well, which you can usually buy with the light. Hanging your light hood with hooks and chains makes adjusting height easy and safe. Also getting a remote ballast is good because its a heavy item that generates heat that you can sit outside your grow area. Most HID light kits come with remote ballasts.

 

You can also use plain old fluoro lights which grow plants well, but not as effective as the HID lights mentioned above. Fluoros are good to use for cloning, keeping mothers, and veg growth, but not the best for flowering. When growing with fluoros keep them real close to your plants, ie within 100mm.

 

The rule of thumb with lighting intensity is you need minimum of 20W per square foot for veg and minimum 40W per square foot for flower, but the more light you have the better your yields will be. The limiting factor is generally heat, as your light gets bigger it becomes more difficult to control temperature, which should be between 24-27 degrees ideally.

 

Bulbs for all lights should be replaced at least once a year.

 

Halogen and normal incandescent bulbs are relatively useless for growing, so don't waste your time with them.

 

Related Topics:

Compact Fluoros

HID Lights

Light Distance

Edited August 28, 2003 by pipeman

[ScuzZ]

Incandescents are useless for growing on their own, they only supply the plant with a large amount of the orange/red spectrum.

 

Using them in conjunction with a Metal Halide and/or High Pressure Sodium light can only benefit the plant.

[Guest weekprik]

A green candlescent bulb of very low wattage is good in the grow room, just incase you need to disturb the plant whilst they are in a dark period,

 

apparenlty the green light is invisable to the MJ plant.