Does more light equal more yield?

More Intense Light = Larger Plants & Fatter Buds = Bigger Yields

After you've germinated your seeds (or rooted your clones), one of the most important things to do right from the beginning is ensure that your plants are getting enough light.

During the vegetative stage, cannabis plants which don't get enough light will tend to 'stretch' up toward the light with a lot of stem between nodes and leaves.

You need to provide enough light intensity to prevent young cannabis plants from stretching or growing too tall and falling over.

Example: The seedling to the left is stretching upwards because it is not getting enough light. The plant is trying to "reach" up towards what it thinks is the sun.

This stretching is not usually a good thing, because these seedings almost always fall over and will tend to grow into tall lanky plants. Tall, tower-like plants are hard to give proper light coverage in the flowering stage and will tend to get lower yields in most indoor setups.

That's because during the flowering stage (when plant start producing buds), higher light intensity is what drives the production of buds.

For most small-scale indoor growing setups, finding ways to increase the amount of light getting to the bud sites throughout the flowering stage is the most straightforward and effective way to increase your final yields.

In order to grow dense cannabis buds indoors, you need strong grow lights

Once your cannabis plant is producing buds, anything you can do to help get more intense lights to the bud sites will tend to increase your yields. Indoor cannabis grow lights provide the highest light levels close to the actual bulb. The further away from the bulb of a cannabis grow light, the less intense the brightness experienced by the plant.

Because of this, it is tough to provide bright light to all the buds on a cannabis plant when the colas are uneven lengths or at different heights. It is most effective and efficient to grow cannabis plants so they have a lot of colas spaced relatively close together and at the same height.

When it comes to improving your yields, the most efficient grow light is an HPS. When I say "efficient," I mean the amount of usable light produced for the amount of electricity needed. Because HPS lights are so efficient, using an HPS grow light during your cannabis flowering/budding phase is the fastest way to improve your yields.

When it comes to improving your potency, LED grow lights seem to help the plant produce more trichomes and bring out the natural odor of the plant, and many growers believe the overall quality and potency of buds is increased when using LED lights during the flowering stage.

A combination of HPS and LEDs seems to provide some of the best benefits of both - big yields plus high quality and potency. This may be because a combination of HPS plus LEDs more closely mimics the autumn sunlight that cannabis plants are exposed to in the wild.

Cannabis plants can use a lot of light, and this upgrade guide will help you figure out the best way to upgrade your grow lights in your budget, but there comes a point when adding more light just doesn't increase yields any more.

Please note: The further your grow light from the plants, the less powerful the brightness but the greater and area the light will cover. The key is finding the right type of lights that give you both the coverage and brightness you need to achieve your goals.

At some point, cannabis hits a saturation point and just can't use any more light. This usually happens when a grower has more than 100W of grow lights per square foot. This also can happen when the grower keeps powerful lights very close to plants. In this case, you can actually increase yields even further by sealing your entire grow area supplementing with CO2.

Just remember that adding extra CO2 to your grow room is a waste of time and money unless you've hit the maximum amount of light that your plants can use, and you will have to completely seal off your grow area (so it's basically airtight) in order to supplement with CO2 effectively. It's important to note that while supplementing with CO2 may increase your yields, it does not affect the quality or potency of your buds..

Watt-for-watt, most grow lights give off about a similar amount of heat. Some lights are more efficient than others (for example HPS is more efficient than CFLs, and will produce more light and less heat for the same amount of electricity), but when it comes to determining heat, wattage is a good way to generally estimate how much heat is going to be generated in your grow room.

That means that 400W of CFLs will produce a comparable amount of heat as 400W HPS grow light or LEDs. One of the big differences is how each of the types of lights dissipate extra heat.

While some MH/HPS lights are installed as a naked bulb under a reflector (cheap "wing" style HPS hoods), MH/HPS lights are often encased within an enclosed hood that allows the grower to hook up the light system directly with ducting so an exhaust fan can be used to expel the heat.

LED models are usually built with heatsinks and/or built-in fans to help disperse the heat evenly without concentrating any heat directly on the plants. Even with these extra bells and whistles, it's still important to use an exhaust system to get rid of extra heat unless it's naturally cold in the marijuana grow tent.