HPS vs MH Grow Light Bulbs – Know The Difference To Pick the Right one

A disagreement has been running for a long time about going for HPS or MH bulbs. They don’t look similar in practical as well as constructed differently. Apart from that, they are different in prices too. Experts have different opinions on using specific lights for specific purposes.

HPS(High-Pressure Sodium) light is a top pick for flowering cycles. On the other hand, MH(Metal Halide) light is an assistant to vegetative cycles. Except for this difference, there is a lot to talk about HPS vs MH grow light bulbs. 

So, here you learn some prime differences between the depicted two lights. The construction material to efficiency- everything will be elaborated precisely. You can receive an outstanding output in your vegetable or flower production after going for these lights.


HPS vs MH grow light bulbs key differences

Some key differences of HPS vs MH grow light bulbs are presented here. Going through this segment can help to simplify your decision. 

Which powering material they use

Both of the bulbs express their power using different materials. The MH bulb uses metal halides to produce light. Though metal halides have a low lifespan, it produces efficient light. Metal halides are used along with vaporized mercury for an optimum result. Besides, the bulbs are made of metal halide and are capable of running around 6000 to 15000 hours. 

On the flip side, the HPS bulb goes for high-pressure sodium to power itself. It’s known as high-intensity discharge(HID) traditionally. The specialty of this powering material is its broader spectrum. High-pressure sodium produces light near 589 nm wavelengths. Therefore, the difference in the powering material between HPS & MH grows lights must be cleared now. 

Their Purpose of using

People may think about versatility as two lights are associated with hydroponic lighting. Specifically, MH light is friendly for vegetative cycles. It’s engineered for accelerating the plants’ growth more effectively. Similarly, the HPS light also has a dedicated side. This light is engineered to produce the flowers nicely. 

Some key factors keep the HPS light ahead in rapid flower growth. The core one is its reddish output. Once it’s autumn, reddish output helps to absorb the natural sunlight. As a result, the flower production rate gets maximized. It should be kept in mind- the more light, the more flower production. 

Which color light do they produce?

The produced color of MH & HPS light is considered as the key dissimilarities among them. Simply, the presence of the high-pressure sodium helps to produce warm-colored light from HPS light. Usually, they tend to have reddish light along with orange or deep yellow output. 

When it’s about MH light, it produces cooler light than HPS light. It emits blue or purple light in general cases. By the way, the bluish-white look is the most common emitted light from Mh light. However, the color may vary in visualization sometimes as there are two types of MH grow bulbs.

How is the quantity of the emitted light 

Before starting, get some briefing about lumens if you haven’t. In a simple assertion, lumens are the unit of emitted light. It represents the amount of light emission from a light source. The higher lumens are the broadcaster of brighter light. Similarly, the lower lumens say about a dimmer light. 

Metal halides help to provide around 80,000-110,000 lumens from a 1000 watt bulb. In addition, a 60 watt of regular bulb produces around 800 lumens. So, the MH bulb produces a huge amount of light undoubtedly. But, the HPS bulbs produce an extremely brighter light than MH bulbs. It produces 130,000-155,000 lumens per standard 1000 watt MH bulb. Therefore, the intensity of HPS light is stronger than the MH light.

How is their working principles 

HPS bulbs contain pressurized sodium as we have mentioned earlier. This helps to contain a lot of pressure inside the HPS bulb. However, an arc gets created after entering the electricity inside the bulb. The newly created arc moves from the ceramic arc tube to get in the bulb. After a certain time, it meets with the sodium vaporizes. In that circumstance, the temperature increases & the light is seen.

There is a different setup when it’s the arc tube of MH bulbs. Quartz glass, mercury & the combination of metallic halides are used here. When it’s a high temperature, the tube gets operated. And the depicted material of the arc tube helps to produce the desired light from an MH bulb. Because of being coated with reflective powder, they easily cope with temperature fluctuation. 

How is their Efficiency & usage time

If the talk is about efficiency, then the HPS bulbs win. HPS bulbs are more than 30% efficient than MH bulbs. The high efficiency represents the capability of producing a high yield. But, it has 3% blue in the spectrum which can cause the plants to be stretched excessively. However, the MH has 78-95% initial efficiency which isn’t good for producing a high yield. 

When the discussion is about using time, the MH lamp wins here. You may need to replace your MH bulb for 6-12 months after 18 hours of regular usage. But, the HPS bulbs may require replacing after using 12 hours per day with the same interval. Therefore, it’s clear that MH bulbs can serve for a very long time, unlike HPS light.

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Having some questions on the distinction between HPS & MH grow light bulbs? Here are the common questions along with straight answers relevant to this topic. 

Is MH better than HPS?

The answer depends on the circumstances. HPS bulbs produce brighter light as well as last longer than MH bulbs. Besides, MH lights are more expensive than HPS lights. Though the MH light has its field, HPS is slightly a good pick.

Is MH or HPS better for flowering? 

A successful flowering story is highly dependent on the amount of received light. It requires a huge amount of light for better output. As HPS produces higher lumens light, it’s more suitable for flowering than the MH light. 

Should I use MH or HPS for veg?

For vegetative purposes, MH light should be a better option. MH light is almost blue which is convenient for plants growing. In practical application, indoor gardeners found MH light as an effective catalyst. So, you should use MH light for veg purposes.

Which is hotter MH or HPS?

MH light is hotter than the HPS light. MH bulbs produce 25-40% fewer lumens than HPS bulbs. This happens for the differences in internal construction. Hence, MH light produces lower lumens as well as seems hotter.


You have grown enough sapient on HPS & MH light through the whole time. The key differences between HPS vs MH grow light bulbs must be cleared now. Different materials are required to produce these lights. Moreover, their output & working principle is different. Here you get a proper concept of these basic things to distinguish between them. 

However, what’s your plan? If you want to cultivate some veg, then go for MH bulbs. Otherwise, you should pick HPS bulbs as it’s good with flower production. Both the lights have their application according to the fields. But, the HPS is cheaper & brighter. So, the winner must be HPS in our eyes. Hence, select the bulb wisely to finish your desired task.

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