The Ultimate Beginner's Guide to Choosing an LED Grow Light

With a determined smile on your face, you threw a few plants in the backyard garden hoping you'd be harvesting some AAA material in a few months, but the time came and you were left defeated with some sub-par material even your poor friends wouldn't consume. Now you're disappointed and wondering how the pros do it so well? Ready for the secret? The pros are taking advantage of sophisticated LED grow lights indoors, and now is the time for you to do the same.

But where do you begin? There are tens of thousands of different options widely available and you're inevitably lost in the world of LED grow lights, unsure what is the best one for you.

For a simple introduction, LED grow lights differ from high-pressure sodium setups or metal halide when it comes to shaping, spectrum, heat load, and power. Even more confused now, right? Don't worry - we will help you in selecting the most optimal LED grow light for your home setup.

Before we get started, this post is an incredible resource for all your queries because it will not only save your efforts in researching the best light but also assure you of having high-quality yields, and top notch product. We included here the definition of LED Grow Lights, Three tips before buying LED grow lights and the importance of knowing how many watts per plant is optimal for you.


Sunlight is essential to plants because it has a vital role in the photosynthesis process since it’s the primary energy source of plants. However, we know that the sun does not exist 24 hours a day, night time will eventually take place and sadly, sunlight is rare during the winter season. Thus, giving such unfortunate effects to your indoor plants.

As an indoor grower or a beginner grower, you must and should know that lack of light would cause harmful effects in your plants like spindly stems, dried lower leaves, etc. To avoid such headaches, using LED grow lights can be beneficial for you!

Grow lights are electric lights that are used for plant growth. But they are not just ordinary light bulbs because these lights are designed to provide the right light spectrum for your plants to get the best results. Its light can mimic the sunlight providing your plants the correct color, temperature, and intensity.

Most growers chose to use grow lights because they make it as a “supplemental light” for their plants especially those who are located in growing areas that cannot receive enough natural light. Another reason is the weather issues (those places who can experience winter and thus, daylight hours are just a few, and it cannot sustain the needed growth of the plants).

As an indoor grower you should always put in mind that for your plants to grow correctly, you must give them the proper nurture they need. This means that you must use the right grow lights so that the plants will receive the correct light intensity. Lastly, remember that using the correct wattage per plant is also very important.


Now that you know the definition and value of LED Grow lights, we're confident that you are now planning to buy one. So, reading the information below will make your life easier!

1. Check the kind of crops you’re growing 

Before purchasing a LED grow light, you must first consider your crop. Remember that there many LED lights on the market today so you should be keen on knowing what you need for your plants to avoid wasting money. There are lights like full-cycle that will make a plant grow from seedling to flower, LED grow lights for indoor medical plants this include but not limited to:

For growers on a tight budget, we recommend you to purchase lights from Horticulture Lighting Group, or Viparspectra. While commercial growers prefer to use LED grow lights that have ETL or UL certification.

2. Check the size of your grow space

It’s vital for you to know the size of your grow space because it will serve as a basis of the size and number of LED units that you’ll need to buy. The ideal rule for LED grow lights is 32 watts of actual wattage per square foot of growing space for flowering medical or flowering plants.

For you to understand more about this thing, take this as an example: if your growing space is 16 square feet, you must buy at least a 500-550 watt grow light assuming if your plants are placed in a single area and you are growing a plant that requires much light. Take note also that vegetative growth for high-light plants needs about half this wattage.

On the other hand, low light plants like herbs and lettuces only need about 11-18 watts per square foot of grow space. But take note that this will solely depend on the crops’ preferred light levels.

To make it easier for you to access the desired wattage of your grow space, we indicate a table below for your reference.

As a Reminded: If you have a larger grow space, you can scale up from these numbers. But, a 1 sq. ft. of grow space only requires about 32 watts of actual 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)


3. Check the available brands of LED grow lights on the market

After reading the above tips for sure you have now an idea of what grow light you should buy, so we would show you now different LED unit options that are available for you.

If you are growing plants from seedling to flower, you must buy a full cycle LED light. But, you may only need these lights for vegging or blooming. On the other hand, if you’re growing plants that need much more light you have options like single-channel lights (on or off) or two-channel lights that have a veg and bloom mode. There are also programmable lights that allow you to set its light schedule, to customize its spectrums, and even change intensities. These programmable lights are:

The listed programmable lights above are considered as the most advanced LED grow lights in today’s LED grow light industry that will surely make your growing business hassle/worry free. There are also different shaped LED grow lights available, like panels, bars, and bulbs. 


Importance of knowing how many watts per plant is the best
LED grow lights are one of the greatest inventions in today’s world. This fantastic invention allows your plants to receive the exact amount of light like in the photosynthesis process.

However, like other inventions, there are also cautions on how to use this properly. We know that the primary goal of every grower in the world is to be able to produce the highest quality plants. Thus, if you’re a grower you must know how many watts per plant you should use.

Mostly, the number of watts that you need to comply will depend on the size of your grow space. Just a quick tip in knowing how many watts you need! Make sure that you allocate 4 square feet per plant and focus on your canopy. In determining the area of your canopy uses the formula, L X W = A.

In reality, there are many ways in determining how many watts you should give your plants. Remember that all plants are unique because of their natural environment and kingdom of classification so, be careful and be keen of applying a certain amount of wattage to your plants because in some instances if the wattage works for this plant, there are possibilities that it might not be suitable to the others.

To avoid misfortunes, you can estimate the wattage using the number of your plants, the height of your plants, the size of your grow space and the phase of growth your plant is currently undergoing, but not do it per single plant.

To guide you further, below is a table of options where you can rely on in terms of how many watts per plant is the best.

Option 1

The 100 watts per plant rule: You have to remember that we are talking about the actual wattage of the light and not the advertised or equivalent watt.

Option 2

The baseline count of 32 watts in every 1 square foot: For instance, if your plant base is 3 by 3 square feet, your plants will need 288 watts.

Take note that if one plant occupies 1 square foot of land, it means that you should administer 32 watts for that plant.

Option 3

Measuring watts based on lumens: Others measure the appropriate watts based on lumens or the light output matched side by side with the wattage. In order for you to know how much you should give.

Take note that plants in a vegetative cycle and flowering cycle need 2,500 and 10,000 lumens per square foot respectively. Thus, you must carefully compute the wattages properly. 


The answer to this question is PLANT DEATH. Yes, you heard it right your plants may die due to the wrong amount of wattage that's used. This is because of the heat being emitted from the light that kills your plants and not just the wattage itself. So make sure to be keen in the remoteness of your grow lights to your plants and to calculate the wattages they needed adequately.


We all know that plant growth is possible if they have received their basic needs like water, air, and light. But, always remember that least or too much of these needs will bring negative consequences to your plants. Thus, the wattage for each kind of plant can differ from the other. This is because it will depend on the variety of your plant, its location, the size of your grow space, the plant’s cycle, and the kind of LED grow light you’ll use. As America’s Trusted Garden Store, we advise you to be careful and be keen in every detail because having a growing business is not a joke. It’s not a piece of cake so be cautious in all the products that you will be purchasing. As a wise grower, you must not be lazy in researching information that can help you. These are just simple tasks that will not only save your growing business but will also prevent you from wasting your money, time and effort.

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