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3 Step Beginner's Guide To Choosing an LED Grow Light for Indoor Plants

on August 18, 2014

Narrowing Down Your LED Grow Light Options in 9 Minutes

Image: NextLight Mega

Updated: June 2018

If you are new to the wonderful world of LED grow lights, you might be in a haze trying to figure out how to choose the most practical light for your grow. LED grow lighting is very different from a metal halide or a high-pressure sodium setup in that LED fixtures vary drastically in shape, spectrum, heat load, and power. But fear not, this article will assist your LED grow light search --- saving you time, money, and assuring you the highest quality crop.

Beginners guide to choosing an LED grow light

This 3 step guide will cover:

  1. The nature of your grow
  2. The size of your growing space
  3. The types of LED grow lights available

1. What are you growing?

Before you decide on an LED grow light, you must consider your crop. All full-cycle, quality LED lights sold on the market will grow a plant from seedling to flower. But some lights are designed for specific types of grows. LED grow lights used to grow indoor medical plants from seed to flower include (but are not limited to) Apache Tech, Amare, Black Dog LEDCalifornia Lightworks, Cirrus LED, EnliteG8LED, Horticulture Lighting GroupKind LEDNextLightOptic LEDSpectrum KingThe Green Sunshine Company (or browse all grow lighting).

Hobbyists that would like to dip their toes into LED lighting and are on a budget might consider the DIY kits from Horticulture Lighting Group, or less expensive brands like Viparspectra or Mars Hydro.

Commercial growers require LED grow lights that have ETL or UL certification. See commercial grow lighting here.

Vertical farmers growing lettuce and/or greens require LED modules, such as those from GE Lighting or Thrive Agritech.


2. What is the size of your grow space?

The size of your grow space will dictate the size and number of an LED units you purchase. A good rule-of-thumb for LED grow lights is 32 watts of actual wattage per square foot of growing space for flowering medical or other large flowering plants. For example, if you measured your growing space to be 16 square feet, you would want to purchase at least500-550 watt grow light (assuming the plants are congregated in a single area and you are flowering a plant that requires a lot of light. Vegetative growth for high-light plants need about half this wattage.).

Image: Optic LED Optic 6 (w/ timing control); 4x4 coverage for flower

Low light plants, such as herbs and lettuces require about 11-18 watts per square foot of grow space. However, this will vary with crop and preferred light levels. Use this chart to determine the correct amount of PPFD and DLI for leafy greens.

Below is a quick reference chart designed to help you determine the desired wattage based on your grow space. If you have a larger grow space, you can scale up from these numbers. Remember: 1 sq ft of grow space requires about 32 watts of actual wattage. 


Grow Space Wattage

2 sq ft (2x1)


4 sq ft (2x2)


6 sq ft (2x3)


9 sq ft (3x3)


12 sq ft (3x4)


16 sq ft (4x4)


20 sq ft (4x5)


25 sq ft (5x5)


30 sq ft (5x6)


36 sq ft (6x6)


40 sq ft (6x7)



Related: Why wattage doesn't matter and PPFD does

3. Types of LED grow lights

By now, you might have an idea of what brand of LED grow lights would be best for your crop and how many watts are required for your grow space. Now, you will discover the different LED unit options available to you.

If you are growing plants from seedling to flower you will want to purchase a full cycle LED light. However, you may only need lights for vegging or blooming.

Lights designed for high-light plants and vegetable growth/flowering have many different options including single-channel lights (on or off); 2 channel lights that have a veg and bloom mode; and programmable lights, such as California LightworksCirrus LEDKind LEDMars Hydro, and Viparspectra that allow you to set light schedules, customize spectrums, and alter intensities.

The programmable lights are by far the most advanced LED grow lights that will make for an almost effortless grow. It is safe to say that the LED grow light industry is moving in the direction of fully automated panels.

In addition, there are different shaped LED grow lights available, including panels, bars, and bulbs. There are even LED tubes that will replace T5 or T8 fluorescent lights.

DIY kits have even recently become available for those who would like to assemble their own light.

Img: DIY LED Kit by Horticulture Lighting Group


Read the article below for a deeper look into what to look for in an LED grow light:


Putting it all together

Now that you have a brand, wattage requirements, and type of LED grow light in mind, you can start your LED grow light search. For questions about choosing your light, feel free to contact LED Grow Lights Depot.

Check out our LED grow light reviews under the resources section in the navigation bar.

Shop All LED Grow Lights

by Dylan on August 18, 2019


by Dylan on August 18, 2019

When you grow with less they say they’re 3000 watts actual wattage is 200 watts which wattage do I go off of the actual or equilivant??

by Cortland Wylie on August 09, 2019

Looking for suggestions or recommendations; putting together a 15×15 foot grow room, how many and wattage led grow lights would work?

by A-ban on April 28, 2019

Can someone tell me if 100 watt LED BULB with the 3 light settings, be enough for 3 plants? More specifically.. 3 10 day old babies.. I know I will have to get more down the line but for now will the 100 watt suffice? Inside a Mylar canopy I made. This is my first grow. Please help!!

by Sunny on February 27, 2019

I am growing medical plants, I have 4 / 4x 8 trays, how many watts LED I will need ?

by Mark Bertram on August 12, 2018

I am using three 500 watt full spectrum LED panels and my buds are airy. I am going to increase to 2000 watts and add two red 630 nm panels for buds and flowers. I am only growing three plants in a 2′ × 4 ‘x 4’ closet right now. Plants thrive on light. You can put them too close, but you can never get enough light. Measure the sun at 1050 watts per square meter. That’s a lot of light!

by liza gomez on February 27, 2018

I just need more light to keep indoor tropical house plants happy and thriving. Can I use these grow lights in the ceiling ( overhead) lighting and still be effective?

by Frank Nitty on February 13, 2018

I’m starting out with a Rubbermaid tub and would like to know what wattage bulbs I need and how many do i need for 2-3 plants

by ADDY on January 22, 2018

I am making a terrarium that is 12" all around. At the bottom I have a few inches of water with a beta fish and some aquatic plants. At the top of my terrarium I have air plants and moss. What would be the right kind of lighting to buy for my terrarium?

by Tommy on January 11, 2018

Hello my question is i want to know what is the best between one 1200 watts LED or four 300 watts LED for a better light dispersion ?

by James on September 24, 2017

Using MEIZHI LED grow light now. All lights are full-cycle, dual-mode, high power draw and Par value! you can buy on ebay, amazon, and aliexpress lool.

by Peter klein on February 06, 2017

I am starting tomatoes from seed and grow them up to 6 in zin height before they are planted outside. What led wattage is sufficient to grow 4 10.5 in x 21 in seed trays. Or you may simply give me a recommended red/blue led fixture or number of specific bulbs that would work. Thanks

by Catherine Stark on September 14, 2016

Thank you

by saiful on August 19, 2016

Is there enough red LEDs for flowering?

by Moses on January 12, 2016

What’s the difference with the growthstar scorpion led grow light and the mars or kindled?

by shah rehman on July 23, 2015

This is very helpful post for beginners,thanks for you contribution.