When growing indoors, there are a lot of factors to consider to create the perfect growing environment. After all, you’re mimicking many properties of the outside world when you decide to venture indoors with your gardening!

With all of the factors to consider, it’s easy to overlook any one of them. Some factors are more forgiving than others, but none is less forgiving than overlooking your choice of indoor grow light.

Simply put: The grow light you choose can make or break your indoor gardening results.

What Type of Gardening Are You Doing?

Before we get into the nitty gritty details of the types of lights on the market, it’s important to answer the question, “What are you even growing in your garden?”

Here are a few common reasons that gardeners turn to indoor gardening — read over these and see if any fit your situation:

  • Starting seeds in preparation for planting outdoors
  • Finishing off plants that need more sun than they’re getting outdoors
  • Propagating and rooting cuttings
  • Growing plants harvested for their greens only (lettuce, herbs, etc.)
  • Growing plants from seed to fruit or flower completely indoors

Once you’ve identified the type of gardening you’re doing, choosing an indoor grow light becomes much easier.

Here are two simple rules of thumb:

  1. If you’re growing plants that aren’t going to fruit or flower, you can get away with less intense lights that put out a lot of blue light
  2. If you’re growing plants that are going to fruit or flower, you should get more intense lighting that put out more orange / red light

For more information on how plants use light, there is an in-depth indoor grow light guide breakdown here.

The Many Types of Indoor Grow Light Technology

As growing indoors has increased in popularity, so have the proliferation of different lighting technologies, with manufacturers making outlandish claims about their effectiveness.

Don’t listen to the hype — instead, look at the science behind these lighting technologies to determine which is best for your needs. Here’s an overview:

High Intensity Discharge (HID)

Marijuana grow room with a High Pressure Sodium (HPS) light bulb

High intensity discharge lighting is a family that contains the following types of lights:

The most common bulbs in this category are HPS bulbs. This is due to their intense output of light in the classic red / orange spectrum that growers use for flowering and fruiting plants.

Metal halide bulbs put out far more blue light, making them a go-to choice for growing plants through their vegetative phases of growth. If you’re only growing plants for their vegetation, then you could consider only using metal halide grow lights.

Ceramic metal halides are relatively new entrants into the HID category. Despite the name, they function quite differently from metal halides. Their primary benefit is their increased efficiency and blended spectral output.

This means that you can use one grow light throughout your plant’s entire life cycle. Many growers are replacing their old HPS or MH setups with CMH ones and reporting fantastic results.

Verdict: Use HPS for flowering, MH for vegetative, or if you can afford to spend more, CMH for both phases of growth.

Fluorescent

Plants are cultivated in hydroponic system

 

Fluorescent lights are the ones that most laypeople are familiar with already, due to their massive popularity as the bulb of choice for all types of indoor lighting. That said, they have fantastic applications in indoor gardening as well.

The primary benefit of fluorescent bulbs is their low energy output when compared to HID bulbs, and their increased lifespan. The sacrifice that you make when choosing a fluorescent over a more standard HID light is the decreased intensity of the light.

On top of that, they’re commonly sold as T5 grow light fixtures with 2700K bulbs (blue light) included, meaning you would have to purchase a 6300K set of bulbs as well if you wanted to use fluorescents for the flowering or fruiting phase of growth.

Verdict: Use fluorescents if your plants don’t require a ton of light and you are growing them through the vegetative phase only.

Light Emitting Diode (LED)

young tomato plant under LED grow light

When LED grow lights first hit the market, growers across the country were ecstatic. Manufacturers of LED fixtures claimed outrageous increases in efficiency for very little loss in intensity.

Like the old saying goes: If it sounds too good to be true, it probably is. However, over the past 5 years, LED technology has matured at an incredible pace and it’s fair to say that LED lights perform as well or better than many other types of lights.

While the technology has caught up to other types of lights, the price for high-quality full spectrum LED lights is still quite high. The cost can be justified by doing a quick calculation of energy savings when compared to HID lighting, but the payoff period can be anywhere from 6-12 months before breakeven.

Verdict: If you can shell out more money upfront for a top-notch LED grow light, it’s probably your best option. But it’ll cost you.

Plasma

Plasma grow lights are one of the newest technologies to enter the scene, and they’re generating quite a bit of buzz. The main selling point is their increased lifespan when compared to most HID bulbs. They also put out a more balanced spectrum of light, meaning that you can use them for both plants that flower and plants that are only grown for their vegetation, like lettuce.

That being said, you have to pay a premium for these benefits, meaning that most growers opt to get one metal halide bulb and one high pressure sodium bulb and use those in conjunction instead to save some money.

Verdict: Until there is more information about plasma grow lights, choose another option.

Go Forth and Grow

Hopefully this article cleared up some of the major misconceptions and questions about different types of indoor grow lights. There’s a lot of confusion around this topic simply due to the complexity of lighting and plant growth in general.

But armed with this overview, you should be able to confidently identify the type of indoor growing you’ll be doing and which lighting technology will perform best for you.