There are daylight bulbs and warm white bulbs; the former better for vegetative growth, and the latter for flowering.
Aside from the price of the actual light, also take into account utilities—all lights will add to your electricity bill every month, but some more than others. High-intensity discharge lights—known as “HIDs”—may be cheaper to buy but can gobble up electricity, whereas LEDs are more efficient and kinder on your electricity bill but usually more expensive to buy.
LEDs also typically run a lot cooler than HIDs, so you may not need extra equipment to cool down your grow space, and one LED can usually be used for both vegetative and flowering growth. Some high-end LEDs allow you to change the spectrum for each growth stage.
HIDs have been the standard in indoor weed growing for decades, but LEDs are quickly catching up to them.
HPS (High-pressure sodium)
There are many types of lights, but below are the four most common you’ll find in a grow room. There are many variations within each of these four types as well, and new lights and technology come out all the time.
Grow lights allow you to control exactly how much light your plants receive, ensuring they get the same amount of light day after day, without the grower having to solve problems with bad weather or cloudy days that happen in an outdoor environment.
However, because of their low price, if you’re new to indoor growing and not sure how often you’ll do it, you may want to invest in an inexpensive HID light at first to test the water.
Other considerations when choosing a cannabis grow light
Here are a few different HID grow lights at different price points.
These fluorescent lights are cheap and efficient and great for vegetative growth. They’re especially great for helping along germinating seeds and small seedlings because they don’t put off much heat and won’t scorch the delicate seeds. They won’t run up your electricity bill too much.
After veg and moving to flower, most growers also agree that switching to a light source with more of the red spectrum is better for flowering. The old standard has been to use either CMH or fluorescents in veg and switch to HPS into flower. This is the tried and true lighting recipe for indoor cannabis growers. By far the majority of cannabis produced in North America today is grown in this way. With the onslaught of LED lighting manufacturers jumping into this new “green rush” of opportunities we are seeing this standard lighting recipe being challenged more and more.
Lighting and Cannabis Qualities
With all of these factors above, how do we answer our initial questions?? Quite frankly, there is no simple answer! Every grow is different – from different: strains being grown, growing climates by geography, style of growers, indoor versus greenhouse, etc. All of these factors will weigh heavy on what is better for you!
HPS or LED: A Key Factor to Consider
Most of these “new to horticulture” LED manufacturers are making claims that you should be using a full spectrum LED in flower to truly maximize plant terpenes and THC levels. But is this really true? See the graph below comparing what parts of the light spectrum is used for photosynthesis compared to the full spectrum light from the sun.