LED Grow Light vs CMH Grow Light
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LED Grow Light VS CMH Grow Light: Guide For Indoor Growing

All growers know that light is important. Plants need light for photosynthesis, and without it, they die. They need the energy they get from light to grow, bloom and produce seeds. When it comes down to it, light is essential to plant life and both LED and CMH grow lights offer the best environments for them.

What you might not know, however, is that the kind of light you give your plants can affect their growth significantly. At different stages in their life, plants need different types of light. The wrong kind of light can stunt growth, whereas the right kind can keep your plants healthy and strong.

For indoor growing, this is especially important. Your plants can’t benefit from the natural cycles occurring outside; you are your plants’ carer. Due to this, giving thought to the kind of light you are providing your plants is essential to their survival. In this guide to indoor growing, we'll explain specifically how CMH and LED grow lights work; with them, you will be able to provide the right light to your plants and, of course, guarantee their survival.

What is CMH grow light?

CMH grow light is another alternative for indoor plant growers. CMH stands for “ceramic metal halides”. They work by pulling low watts while covering a large area. Their main benefit is how energy-efficient they are. Unlike LEDs, CMH grow lights use a bulb (or two in some places). A CMH grow light is more likely to look like what you expect a grow light to look like.

CMH grow lights have been popular for a long time because their bulbs last for a long time, and their colour-rendering index mimics the sun’s spectrum closely – perfect for indoor growers. Around 11% blue light is in their spectrum, making CMH bulbs well suited for growing seeds to flower with only one bulb. CMH grow light will also cost you less upfront. The initial purchase of a CMH grow light will be around half that you would pay for an LED grow light.

However, CMH bulbs boast less longevity. Though they can last a long while, you will have to replace them at some point. The biggest cost difference for CMH and LED is that CMH grow lights’ bulbs have to be replaced when you want red light or blue light. This, of course, will add cost.

Pros and Cons CMH Grow Lights

How do LED grow lights work?

When looking for light-emitting diode. LED grow lights are made up of hundreds of these LED chips, which allows for many of the benefits they possess. Each of these LED chips can be specifically set to emit a chosen spectrum of light. With each of the many chips set to different spectrums, LED grow lights can offer your plants a large surface of full-spectrum light.

You can get LED grow lights in many different forms because they are made up of many different chips. You can get long strips of LED grow lights – perfect for greenhouse growing – or panels, which are more suited to indoor growing.

LED grow lights are easily adjustable. With little effort, you can dim your LED lights from blue to red spectrum. This allows you to have extreme delicacy when looking after your plants in every stage of their growth. All this, without having to move your plants to a finishing room or change the bulbs in your grow light.

In the long run, LED lights will save you money. They don’t need to be replaced – you buy them once, then you’re set – and they don’t harm your energy costs as much as other bulbs. The usable light they give off is at a lower wattage than other light options, burdening you with less of a cost. Typically, they save 15% on energy costs.

However, LEDs have a high upfront cost. The price of an LED grow light will differ, depending on where you buy it from, but it can range from $100 to $2,500. As you can see, some of these prices can be quite steep.

Pross and cons LED grow lights

Why Use LED Grow Lights or CMH Lights

Both LED and CMH grow lights boast manifold benefits. When it comes down to it, the best bulb to pick will depend on your own personal growing habits, spaces, and budgets. To help you decide, this table outlines the differences between the two grow lights.


LED grow lights

CMH grow lights

Light output

LED grow lights give your plants a very specific set of light wavelengths to promote growth. The particular light spectrums and colour lights can be chosen and changed with a dial, allowing for different lights at different stages of development.

CMH grow lights have different bulbs for different stages of the process. One focuses on blue light, the other on red. CMH grow light’s focus in the yellow/orange spectrum of light allows for a very natural-looking light that mimics the sun.

Heat output

Depending on the LED grow light you buy, the heat output will differ. However, most LED grow lights are low heat and low fire risk.

CMH grow lights run cool due to their ceramic bases. Even though, as they have a bulb, you might expect them to heat up, the ceramic base ensures they stay cool.


LED grow lights take up little space. They can be kept very close to the plants and so are great for those who don’t have plenty of space to spare.

CMH grow lights don’t take up too much space, but the size will depend on the type of bulb you choose.

Ease of use

LED grow lights are incredibly easy to use. You can adjust light levels and colour spectrums with a turn of a dial. Bulbs do not need to be replaced when the plant moves through different growth stages.

CMH grow lights are favoured by beginner growers because the technology is easy to understand and use. However, the grower must put in a little more effort: bulbs must be changed depending on whether your plant needs red or blue light.

Upfront cost

The upfront cost of LED grow lights is steep. They often are above $100, and can go up to $2,500, depending on the type you go for.

A CMH grow light has a much lower upfront cost. Typically, it will not cost you more than $500, but prices can be as low as $80.

Replacement costs

LED grow lights do not need to be replaced for different growing stages or overuse.

CMH grow lights require yearly bulb replacements. This cost will be double if you have a dual fixture grow light. On top of this, different bulbs are needed for different stages of growth. For example, you need a 4100K bulb for the vegetative stage, a 3100K for the flowering stage, then back to the 4100K from then on.

Energy usage

LED grow lights save around 15% (average) on energy costs, due to emitting usable light at a lower wattage.

CMH grow lights are incredibly energy-efficient. Though they may cost a little more to your energy bills than LED grow lights on average, they still are cheap to run and efficient.


As you can see, there are some areas in which LED and CMH grow lights diverge and others in which they offer very similar things. So look at the areas that affect you most as a grower, and see which gives you the best plan.

Best valuable LED grow lights and CMH grow lights on the market

So you’ve decided to buy an LED grow light, or a CMH grow light. Your next dilemma is which of the many products on the market you want to buy. Your choice will depend on what you want to get out of a grow light, but here are three options that may suit you well.

  1. Growealth LED grow light

The LED grow lights from Growealth come in three different wattages: 150W, 300W, and 480W, depending on your needs, ranging in price from $169.99 to $789.99.

These grow lights have four modes, offering different light levels, incorporating UV, IR and full-spectrum light. You can easily switch between these modes – quite literally with the flick of a switch. The full spectrum of light offered has specifically been optimized for rapid and efficient growth throughout the plant life cycle. As a result, it can adapt to all types of plants.

The package includes everything you need to start growing: fixtures, accessories, and, of course, the lights. It arrives within days and has free shipping and returns.

  1. Luxx Lighting – Luxx 630W CMH

Luxx Lighting’s CMH grow light offers two 315W CMH bulbs to grow your plants with. It has a three-year warranty and can be delivered within three days.

This bulb runs cool, so it can be used in small spaces. The light produced by Luxx Lighting’s CMH grow light works specifically to reduce shock during the transition to the flower cycle.

  1. 1000W Lunar LED grow light

This high power LED grow light is incredibly energy-efficient. In addition, it has a low heat output, allowing your grow room to keep cool.

Cannabis plant with red light

As this grow light is stronger than most on the market, it is perfect for vegetation and flowering your plants to their best outcome.

At $412, the power of this LED grow light is incredibly cost-efficient too.

  1. Maxibright Daylight CMH 315W Ipac Kit

This CMH grow light is only $82. It comes in both blue and red lights (each must be bought separately). The kit includes the bulb, a euro reflector and a powerpack ballast.


Both LED grow lights, and CMH grow lights offer benefits to your plant growth. Depending on how involved in your plants you wish to be, the ease of use of LED grow lights versus CMH grow lights may affect your decision. As may price. Questions of space, heat, and light may all factor into the decision you make.

When it comes down to it, LED grow lights may be better for more experienced growers, whereas CMH grow lights offer a great starting block for beginners in indoor growing. The high upfront cost of LED grow lights works best for those who can get the most out of this high-end growing kit.

However, whichever light you choose for your plants, you will end up with good vegetation, growth, and flowering.

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