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How To Choose The Best Grow Lights

Supplying enough light to your plants is one of the most important aspects of effective indoor gardening. Gardeners utilize grow lights to create artificial sunshine. How to choose the best grow lights? What do you need to focus on?

Artificial lights are not all equal in function for your indoor weed crop. The most common grow light choices are HID, LED, and Fluorescent.

Each has its own set of advantages and disadvantages. Furthermore, you should consider the demands of the plants while choosing the right sort of light.

This article has included more detailed information. Let’s scroll down to discover!

Factors to Consider When Choosing a Grow Light

  • Plant space: The quantity of lighting for optimum crop development depends on the size of your grow space. You have to determine the amount of the illumination surface that one lamp unit can service by determining the dimensions of your whole grow room. You may calculate the number of light units needed by utilizing this information.
  • Heat release: Cannabis plants can get burned by lights that emit a lot of heat. You shouldn’t put the lights too close to your plants. The lamp’s heat output capability and distance affect the amount of heat that reaches the plants.
  • Consumption of energy: Your total room’s lights must be on for around 10 or 11 hours every day. Although available unit selections may exceed 1000 watts, light bulbs with less than 300 watts are ideal.

Understanding Grow Light Basics

You also need to know some terms used when talking about grow lights.


Intensity is the quantity of light that can approach a surface at a certain distance from the source of light. For example, a mega bulb placed 12″ from a surface could reach the level of light intensity as a softer bulb placed 2″ away.


The color implies the hue of the grow light. Most grow lights produce full-spectrum light. Plants mostly utilize light from the red and blue portions of the spectrum. They employ only a little green or yellow light. Red light increases flower production whereas blue light promotes vegetative development.

Cannabis prefers red or blue lights to the green and yellow options


The amount of hours a plant obtains the light in a 24-hour cycle is the duration. We may manage it by switching the lights on and off. To be more convenient, we can use a programmable schedule instead.


You should be able to find information on the light’s footprint on any grow light you select. The footprint describes the coverage space that goes under the luminaire’s beam.


Wattage simply indicates how much energy the light consumes. However, when comparing the light sources of distinct grow lights, it’s vital to consider more than just the watts.

As you see, efficacy, a grow lamp’s capacity to convert electricity (Watts) into light, is more crucial. Because efficiencies change based on the kind of light, even bulbs with the same wattage might produce significantly different light volumes.

Among most LED lights, there is a difference since some utilize more effective drivers and diodes. The lights may consume the same amount of power. However, the difference in drivers and diodes results in higher light output.

When searching for the grow lights, choose those that have a high-efficiency rate. You may get the lightest output per watt of power consumed.

What Kind of Indoor Grow Light Should I Use?

HID, LED, and Fluorescent are the three most popular forms of lighting. Each type has advantages and disadvantages. Let’s have a closer look at them.

A. High Intensity Discharge (HID)

You may find two kinds of HID lights: HPS and MH. The distinction is that MH lights provide blue and cool light. Meanwhile, HPS lights are often red.

As a result, MH lights are superior for vegetative growth, whereas HPS lights are ideal for the flowering stage.

When compared to other kinds of lights, HID provides a significant quantity of illumination power. This kind is common in big commercial growth. Its strong heat and light necessitate a complete exhaust fan to maintain the temperatures.

HID provides a significant quantity of illumination power

Pros of HID Lights:

  • HID lights are less expensive upfront than high-end LEDs.
  • Even for novices, it’s simple to install and use.
  • They produce great yields.
  • The lights are solid and effective.
  • It’s a good choice for the blooming and growing section.

Cons of HID Lights:

  • They generate heat, which can increase room temperatures or harm the plants.
  • To use them, you’ll need some extra equipment, such as electrical ballasts and reflectors.
  • HID bulbs weaken with time and you have to replace them regularly.
  • HID lights consume more energy and might drastically increase your electricity costs.

B. Light Emitting Diodes (LED)

LED lights use a lot less power than other alternatives. However, some budget gardeners may find its energy-saving features to be prohibitively pricey. LED lights don’t create much heat like other bulbs. LEDs are the way to go if you are looking for a light that you can use for a long time.

LED lights don’t create much heat

Pros of LED Lights:

  • LED grow lights are the most energy-efficient.
  • In comparison with HID lighting, LED lights operate significantly cooler and generate very little heat.
  • You can lower cooling costs and the risk of plants caught on fire.
  • The majority of commercial LED grow lights appear to be plug and grow, requiring no extra ballast.
  • LED lights are supportive for both vegetative and flowering stages.

Cons of LED Lights:

  • High-end fixtures with cutting-edge modules might increase the total cost.
  • The outcomes of low-cost brands and models can be poor.
  • Yields might be lower than the HID.

C. Fluorescent Lights

The majority of home gardeners will begin with standard fluorescent lights. They consume very little electricity and release very little heat. Hence, you can place them near your plants.

They’re especially well-suited to small-scale crops. These bulbs include standard sockets, making them suitable for any regular light fixture. Also, they do not necessitate the use of any specific tools.

fluorescent lights
Fluorescent lights are suitable for small-scale crop

Pros of Fluorescent Lights:

  • The cost is low, and it is easily accessible.
  • It’s simple to install and utilize.
  • Beginners will enjoy it.
  • Different color temperatures and wattages are possible.
  • It consumes very little electricity and so saves electricity.
  • It doesn’t get too much heat.
  • An ideal choice for seedlings and clones.

Cons of Fluorescent Lights:

  • Only effective for growing 1 to 2 plants due to low intensity.
  • Flowering may not be optimum, so the yields are poor.
  • It has a lower life expectancy than other kinds of lights.

Lighting Plan for Transplants

New seedlings and young marijuana benefit from full-spectrum light, which includes both red and blue wavelengths. Customized fluorescent and LED grow lights, as well as less costly bulb lights, will do the job. For optimum results, place the light source about 6 inches away from the plant leaves.

LED and fluorescent are the ideal choices for transplant

You can hang the lights on chains or raise your plants on a tray or a table for easier moving. Before utilizing your lights every year, carefully wipe out the light bulbs to eliminate grime and dust. Careful maintenance can ensure the proper operation.

Lighting Plan for Flowering Plants

Regarding indoor cultivation, red lights are critical for encouraging plants to blossom and yield. Look for LED lights and fixtures that are particularly suitable for growing cannabis plants.

There are LED lights called plant-friendly. Some energy companies name them “high-output lights”. They are often twice as powerful as regular LEDs.

Cannabis plants thrive in full sun, arid conditions. Hence, those ultra-bright lights are ideal for growing them. Flowering plants should be lit between 16 and 18 hours each day.

lighting plan for flowering plants
LEDs also work well for the flowering stage

How Much Light Do You Need For Cannabis Grow?

After you’ve chosen the type of grow light, you’ll need to figure out how huge of a bulb you’ll want for the available area.

To begin, figure out how much room you’ll need to light. You should aim for 20 to 40 watts each square foot as a general rule. Divide your bulb’s wattage by 20 (for example, 1,200 watts divided by 20 is 60), then by 40 (for example, 1,200 divided by 40 is 30).

The result will tell you what the light intensity level is at its most severe. You can illuminate between 60 and 30 square feet of internal landscaping with a single 1,200-watt device.

calculations for the light intensity needed
Do some calculations for the light intensity needed

Also, ensure that the wattage of your lights matches the wattage that your fixture can manage. A 400-watt bulb, for example, should not go with a 250-watt circuit.

As you see how effectively your plants thrive, make adjustments to your setting. Shift the positioning of your plants or light fixture farther or nearer the light source to decrease or increase the light intensity.

FAQs – Grow Lights

How do you read a grow light?

There are two major metrics for reading a grow light. PAR is the first tool. It’s simply a measurement of light generation in the 400 to 700nm photosynthesis band.

A spectrometer is the second tool. You use it to measure the spectrum of light. PAR demonstrating intensity, as well as a spectrum demonstrating that this intensity is in the right spectrum ratio for what the plants can really use.

How many watts do I need per square foot of growth space?

You should aim for 20 to 40 watts each square foot as a general rule.

How close should a grow light be to the plants?

You should hang the light no more than 12 inches away from your plants. Bear in mind that a fluorescent light reduces its power after 12 inches. As a result, don’t elevate it higher than 12 inches.

What color light do my plants grow best in?

It’s crucial to have the proper quantity of each wavelength. Plants grow under a light that is predominantly blue and red with a minor bit of yellow and green. White light has no impact on your plants.

How should I hang a grow light?

You should hang the regular lights around 24 to 36 inches above your plants. If you employ stronger lights, hang them from 48 to 62 inches up above your plants.

How far should I place the seedlings from growing light?

Different plants vary in terms of light intensity. Most seedlings produced for the garden, on the other hand, will require greater light intensity to thrive. The seedlings should be around 2 to 4 inches away from the light in general.

How can I make a grow light stand?

After gathering the lights, use baling wire to secure the light fixtures to the bottom of the shelves. Then, you need to screw in the lights. After that, add some foil lining to assist in emitting light and keep the growing space warm.


Above is the comprehensive guide on how to choose the best grow lights. Each type of grow light serves a different purpose. You should opt for the light after considering your crop scale and plant stage.

Besides, the intensity, spectrum, duration, and footprint are all important factors for your plant development. Don’t miss anything if you want a large yield.

If you need any further information, please feel free to ask. Hopefully, you will find this article helpful.

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