One of the vital elements a cannabis plant requires is light. During photosynthesis, a plant converts light energy into chemical energy, allowing it to grow strong and healthy, and with cannabis specifically, light also fuels bud production.
When growing outdoors you can harness the power of the sun, however in an indoor setting, sunlight is mimicked with the use of grow light bulbs, which intend to display the same spectrum of light as the sun.
Grow lights allow you to regulate exactly how much light your plants receive, making sure they receive the same amount of light every day, without the grower having to fix problems with bad weather or cloudy days that happen in an outdoor setting.
Some grow lights are more costly than others, but also more effective, saving money in the long run. Some lights are bulky with several parts, 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 start. Here's a guide to four basic types of grow lights on the market and the advantages and disadvantages of each.
Kinds of Grow Lights
There are many types of lights, but below are the four most common ones you'll find in a grow room. There are many variations within each of these four types 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 components can be more expensive. There are a many acronyms, but do not be alarmed.
HID (high-intensity discharge) is an umbrella term under which MH and HPS bulbs fall, which we'll go over more below. These types 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 cultivating for decades, but LEDs are quickly catching up to them.
Both types of HIDs are usually affordable to buy but will eat up electricity. HIDs throw off a lot of light and heat, which the plants need to grow and get potent. However, they run hot, contain heavy metals, and ballasts can stop working.
Nevertheless, due to their low cost, if you're new to indoor cultivating and unsure how frequently you'll do it, you may want to invest in an inexpensive HID light in the beginning to test the water.
MH (Metal halide)
These bulbs contain mercury and metal halides, produce a bluish light, and are commonly 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 currently available.
HPS (High-pressure sodium)
These HID bulbs normally have sodium, mercury, and xenon, and produce a yellow/orange light, and also are generally used for flowering plants. Some cultivators will start plants under MH bulbs and switch them to HPSs when plants enter the flowering stage, using the same hood. These lights also need a ballast.
CFLs (compact fluorescent lamps) are fluorescent lights similar to what you would see in a school or office building, but smaller. For growing marijuana, they are usually called "T5s"-- the "T" represents "tubular" and the "5" represents 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 effective and good for vegetative growth. They're especially good for helping along germinating seeds and small seedlings because they don't emit much heat and will not burn the fragile seeds. They won't increase your electricity costs too much.
The disadvantage to CFLs is they aren't great for flowering plants, and growers will typically use a different type 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 fit 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 relatively new to the marijuana growing scene, compared to HPSs, MHs, and CFLs, but they are quickly proving to be the way of the future. LEDs may be more pricey to buy initially, but they are much more effective and kinder to the environment and your electricity costs. Some cities even give tax breaks to commercial growers that use or change to LEDs because they're better for the environment.
LEDs also usually run a lot cooler than HIDs, so you may not require extra equipment to cool off your grow space, and one LED can typically 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 emerge constantly, but knockoffs abound. There are a lot of inexpensive LEDs that don't generate the right spectrum of light for plants.