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How To Choose The Right Indoor Marijuana Grow Lights

Growing marijuana indoors has its advantages and disadvantages just as growing the cannabis plant outside does.
What Lights to Use For Growing Marijuana Indoors

Growing marijuana indoors has its advantages and disadvantages just as growing the cannabis plant outside does. Indica marijuana strains are perfect for growing marijuana indoors because of their short and wide plant growth compared to the thin and tall growth of sativa marijuana strains.

When setting up a home grow location its absolutely essential that you choose the right lights at the right growing stages for your marijuana plant. Growing marijuana indoors grow in two stages; the vegetative stage and the flowering stage.

The Vegetative Stage (A)

When a marijuana seed is first planted it enters the vegetative stage where it begins to grow out its stems to prepare for budding and the flowering stage. The vegetative stage can last anywhere from 1 week to about 40 days and requires a standard day light cycle of 18 hours on – 6 hours off for the most effective results. Some growers prefer a 24 hour light cycle for the vegetative stage, which will stimulate quicker and faster growth. Either one should work fine, however, a standard day light cycle may work better for pure Indica weed strains.

The Flowering Stage (B)

After 40 days or a couple weeks (or whenever you want to end the vegetative stage) the light cycle needs to switch to 12 hours on – 12 hours off in order to start the flowering stage, which starts as soon as you switch the light cycle allowing the plant to produce buds. When choosing when to enter the flowering stage, after about a month use good judgment based on plant size and health. For maximum growth most strains can enter the flowering stage after about 40 days as long as the plant looks healthy and is tall enough.

Keep in my mind that different weed strains combined with various growing techniques will produce different results at different times. Some strains may take longer to mature and prepare for the flowering stage compared to others. If you know the exact marijuana strain seed you have its a good idea to look up the average height when grown indoors. This will give you a perfect measurement of when your plant has matured and is ready to enter the flowering stage.

Ok, so now to the point of the article. What lights should I use for the vegetative and flowering stages?

The best lights to use for the vegetative stage would be any kind of fluorescent bulb. This is because the cannabis plant loves tons of blue light in the spectrum which can come in the form of many different fluorescent bulbs which are common for home growers in the vegetative stage because of their low height output and efficient blue hues of light. I wouldn’t recommend using high energy and heat consuming Metal Halide lights (which give off nice blue hues of light) unless you have a license to grow medical marijuana and live in a state where its legal.

When you use lights that consume a lot of electricity, you run the risk of having your energy bill draw suspicion from authorities. Luckily, there’s really no need to deal with anything other than blue hue fluorescent bulbs for indoor growing until you get to the flowering stage. This is where a High Pressure Sodium light would works best (alone or with the fluorescent lights) and you can get away with it because the lights will only be on only 12 hours a day which will consume less energy and heat.

You can see in the diagram below that the cannabis plant requires blue and white light (Metal Halide & Fluorescent lights) for the vegetative stage (A), and red, orange, and yellow light (High Pressure Sodium Bulb) for the flowering stage (B).

Light Spectrum For Growing Marijuana

Note: Metal halide and high pressure sodium lights require a ballast for proper use and may consume a high amount of energy with high levels of heat output. A great way to save money on energy bills and to reduce heat in your grow room, consider using LED grow lights. You can find out more about LED grow lights by clicking on the banner below:

Smarter LED lighting solutions for plant science and horticulture
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