Marijuana Lights or grow lights enable the grower to extend their growing season to the whole year. Marijuana lighting also give growers a large amount of flexibility in the growing process. Because the marijuana grow cycle is dependant on the hours of light the plants receive, artificial lights enable the indoor grower to begin the flowering process whenever they want. There are naturally disadvantages to using grow lights to grow marijuana. They often cost quite a bit especially the good ones. Also there is the cost of the electricity. Growers usually use either MH (Metal Halides), HPS (high pressure sodium lamps) and Fluoros. As a rule of thumb, MH work best in the vegetative period and HPS work better in the flowering phase. A combination is often used. Fluoros do work, however they are usually in commercial marijuana lighting.
Read below for a more detailed knowledge or check out a complete guide to weed lights at Grow-Marijuana.com.
The amount of light that marijuana receives determines the quantity and quality of the plant and buds. The photo period is the number of light hours verses dark hours in 1 day.Marijuana usually needs 12 hours of dark each day to begin flowering.
Under continuous light Marijuana will grow but will not flower and produce buds. Darkness makes the plants produce flowering hormones and regular undisturbed darkness will make them stop growing and start flowering.
Outdoors the seasons control the photoperiod. As the summer comes to an end and the nights become longer cannabis flowers ready to produce seed. Indoors you control the photoperiod so you can start flowering whenever you wish.
Sunshine is more intense than any artificial light and is free. However some places on earth just don't get enough. Greenhouse growers can supplement sunshine on dull days with electric lights hung in the greenhouse.
The most efficient types of marijuana lighting are sodium or metal halide high intensity discharge (HID) lamps. Metal halides are strong in the blue spectrum of light and are good for growth. Sodium lights are strong in the red spectrum of light and are good for flowering.
High intensity lights also come with different shades. All combinations work OK but its best to use sodium bulbs in horizontal shades for flowering. Plan on giving 30 to 60 watts of light for each square foot of growing space.
Lights get hot and can burn plants that get too near. However the closer the light to the plants the more intense light they receive. In general keep 400 w lights 30 to 45 cm above plants and 1000 w lights 45 to 75 cm above plants.
Fluorescent light is fine for the growing stage but flowering plants really need more intense HID light. If fluorescents are your only choice choose alternate rows of "Cool White" and "Warm White" bulbs and place them only a few cm's away from your plants.
Marijuana grow lights
The purpose of this FAQ is to help limit the spread of misinformation regarding effective artificial lighting systems, and help those who choose to grow marijuana plants under artificial lighting make an informed decision before buying a grow lamp.
Most of the information comes from printed
sources, and some from electronically distributed files. Though information also comes from a network of experienced growers who have tried various types of marijuana lighting.
There are three major types of lighting systems available right now for growing marijuana:incandescent, fluorescent, and high intensity discharge. Incandescent lights are horribly inefficient (especially the screw-in "grow bulb" type) and really not an acceptable option for marijuana plant growth. Although they are inexpensive to purchase, their cost of operation makes them the costliest source of light. Therefore avoid at all costs.
Until the early 1980's most indoor marijuana growers used fluorescent lights to
illuminate their garden. These tubes have tremendous advantages over
incandescents. They emit about 3 times as much light as an
incandescent (given the same wattage), and the light spectrum is one
that plants con use more effectively.
High Intensity Discharge Lamps (HID's)
You will find pictures of marijuana lights here.
The following chart shows how much light each lamp emits, and the area that it covers adequately:
Timers for the garden
The lighting system needs to be switched on and off automatically so the marijuana plants receive 18 hours of light per day during vegetative growth and 12 hours per day when flowering. most hard ware stores and other electronic shops sell timers. they are usually very cheap . It may be advisable however to purchase a more robust timer if your serious like a pool timer.
Lamp # of Lumens Sq. Ft
4'FL (CoolWhite-40W) 2,960 1-2
When choosing which marijuana lights to use in your garden, we suggest a combination of MH and HPS with flouros used in cloning and early seedlings. It is also important to chose the right shade. Some will reflect light much better than others. Any good supplier should be able to recommend the best for your requirements.