One of the crucial components a cannabis plant requires is light. During photosynthesis, a plant turns light energy into chemical energy, allowing it to grow strong and healthy, and with marijuana in particular, light also fuels bud production.
When growing outdoors you can harness the power of the sun, yet in an indoor environment, sunlight is mimicked through the use of grow light bulbs, which try to present the same spectrum of light as the sun.
Grow lights enable you to regulate precisely how much light your plants receive, ensuring they get the same amount of light day after day, without the grower needing to fix problems with bad weather or cloudy days that occur in an outdoor environment. Some grow lights are more costly than others, but also more effective, saving money over time. Some lights are bulky with many components, some light in weight, and some are better suited for young or mature plants.
There are various types of lights out there, so it can be intimidating to know where to begin. Below's a guide to four basic kinds of grow lights on the market and the benefits and drawbacks of each.
Types of Grow Lights
There are many kinds of lights, but below are the four most common ones you'll find in a grow space. There are several variations within each of these four kinds also, and new lights and technology emerge all the time.
Lights have fixtures and bulbs, and some need a ballast. Depending on the type and model, the bulbs or the fixtures can be more costly. There are a lot of acronyms, but don't be alarmed.
HID (high-intensity discharge) is an umbrella term under which MH and HPS bulbs fall, which we'll discuss more below. These kinds of lamps have a hood that reflects light and bulbs that are enclosed capsules containing a gas, as opposed to bulbs you 'd find in your house, which have a filament that heats up.
For HIDs, light occurs as an arc between two nodes inside the bulb. The gas contained in these bulbs is what makes MHs and HPSs different. HID bulbs are usually more expensive than the reflective hoods that hold them.
HIDs have been the standard in indoor weed growing for decades, but LEDs are quickly catching up to them.
Both types of HIDs are typically inexpensive to buy but will eat up electricity. HIDs throw off a lot of light and heat, which the plants need to grow and become potent. However, they run hot, contain heavy metals, and ballasts can stop working.
Nevertheless, because of their low price, if you're new to indoor cultivating and unsure how often you'll do it, you may want to invest in an affordable HID light at first to test the water.
MH (Metal halide)
These bulbs contain mercury and metal halides, produce a bluish light, and are generally used for vegetative growth. They need a ballast to regulate the current. In the past, ballasts have been big and bulky, however digital ones are now available.
HPS (High-pressure sodium)
These HID bulbs usually have sodium, mercury, and xenon, and produce a yellow/orange light, and are typically used for flowering plants. Some cultivators will start plants under MH bulbs and switch them to HPSs when plants go into the flowering stage, using the same hood. These lights also require a ballast.
CFLs (compact fluorescent lamps) are fluorescent lights similar to what you would find in a school or office building, but smaller. For growing weed, they are typically called "T5s"-- the "T" stands for "tubular" and the "5" refers to its diameter, "⅝".
There are daylight bulbs and warm white bulbs; the former better for vegetative growth, and the latter for flowering.
These fluorescent lights are cheap and efficient and great for vegetative growth. They're especially good for helping along germinating seeds and small seedlings since they do not put off much heat and won't burn the fragile seeds. They won't increase your electricity bill too much.
The disadvantage to CFLs is they aren't great for flowering plants, and growers will commonly utilize another kind of light to finish plants. CFLs just don't generate enough intense light for plants to pile on weight.
Fixtures come in all shapes and sizes and can normally accommodate 4-12 long fluorescent bulbs; a standard size is 8 bulbs. Fixtures usually have a reflective material to bounce light in one direction, down on your plants.
LEDs (light emitting diodes) are fairly new to the marijuana cultivating world, compared to HPSs, MHs, and CFLs, but they are quickly proving to be the way of the future. LEDs may be more expensive to buy initially, yet they are much more efficient and kinder to the environment and your electricity costs. Some cities even give tax breaks to commercial cultivators who install or switch to LEDs since they're much better for the environment.
LEDs also typically run a lot cooler than HIDs, so you might not require extra equipment to cool off your grow space, and one LED can usually be used for both vegetative and flowering growth. Some high-end LEDs enable you to change the spectrum for each growth stage.
New LED grow lights appear constantly, but knockoffs are all around. There are several cheap LEDs that don't generate the best spectrum of light for plants.