400W vs 600W vs 1000W HPS

400W vs 600W vs 1000W HPS: Choose The Right One!

HPS light is the most essential element for indoor growing. However, with the option of many wattages choosing the appropriate one is confusing.

So, which one is better when it comes to 400W vs 600W vs 1000W HPS?

400W light uses the least electricity compared to 600W and 1000W HPS. However, 400W can cover 3.20 square meters, whereas 600W covers 3.34 square meters. But 1000W can cover the most at 4.55 square meters. Also, you can grow 6-8 plants with 1000W. But only 1-3 plants with 400W and 4-5 plants with 600W.

This information is very useful. However, you need more in-depth knowledge about each wattage of HPS light.

So, let’s get going.


There are many myths surrounding the HPS light and growing hemp. Some of those are true, some are just not. 

Source: todaysgardener.com

So, before starting the comparison, we will bust the myths. That way you can make a better selection of HPS light for growing hemp.

1000W HPS Light Is Required to Grow Hemp.

No, you absolutely don’t need a 1000W HPS grow light for Hemp. In many cases, you may end up losing 60% of the wattage.  Because the hemp plants can grow within 400W-600W. Thus, you are nothing but wasting your energy.

However, 1000W HPS lights are useful in larger areas. Also, if you are planning to grow more plants, 1000W HPS light is the ideal option. But, for a small area, 1000W HPS light is not always required.

Too Much Light Help to Grow Hemp Faster.

Again, it is another misconception. Too much light will never help your Hemp to grow faster. Actually, it will burn the plants. Your plants will go to photoinhibition. It is a situation where plants use more energy to utilize light.

As a result, your plants will end up being dead or unusable. This is such a waste of time, energy, and money.

Watering Your Hemp Plant Under HPS with Juice Will Enhance Its taste.

This myth is true. Many use apple juice or molasses to enhance its flavor. Although, watering with juice should be done before a week of picking off hemp. That way the sugary, sweet smell will be intact.

Now that the myth-busting has been done, let’s move on. 

Quick Comparison

HPS (High-Pressure Sodium vapor) light for growing hemp is very useful. However, many people don’t know which HPS light they actually need. So, what are the differences between 400W, 600W, and 1000W HPS lights? 

Apart from wattage differences, each light has significant differentiating accomplishments. So, choosing the right one is necessary. Otherwise, problems like no buds from hemp after 4 weeks can arise.

With that said, let’s see a quick comparison between 400W, 600W, and 1000W HPS lights.

Differentiating Factors400W HPS600W HPS1000W HPS
Wattage400 Watts Per Hour600 Watts Per Hour1000 Watts Per Hour
Actual Wattage150-380 Watts270-500 Watts900 Watts
Required Wattage460 Watts640 Watts1100 Watts
Coverage Area3 Square Meters3.34 Square Meters4.55 Square Meters
Working Frequency25-40hz25-65hz25-80hz
Light Output50,000 Lumens90,000 Lumens120,000 and 145,000 Lumens
Heat Least TemperatureGets Hotter than 400W HPSGets Hotter than 600W HPS
Number of Plants 1-3 Plants4-5 Plants6-8 Plants
PriceCheck Price on AmazonCheck Price on AmazonCheck Price on Amazon

This quick review is useful indeed. However, it is not enough. You need to dive deeper for a better understanding.

So, let’s move on to the next section.

In-Depth Comparison

Here I will talk about in-details regarding each HPS light. 400W vs 600W HPS is somewhat similar. But, 1000W is the game-changer. But, which HPS light do you require?

Source: zamnesia.com

By going through this section, you will find out the appropriate one. Also, knowing how much light is needed for an 8X8 grow tent yield is important as this is the standard size of most vegetations.

Now, let’s head-to-head compare each HPS light.

Required Power

Higher wattage means higher power consumption. But how much power does each HPS light require?

For starters, 400W HPS lights run 400 watts per hour. So, each hour it’s consuming 400 watts. However, the actual wattage of 400W HPS light is 150-380 Watts. Also, you need to have at least 460 watts of power supply to use it.

On the other hand, 600W HPS lights run 600 watts per hour. Nevertheless, you need to have 640 wattages of electricity supply to run this HPS light. Compared to 400W HPS, 600W HPS lights require and consume more power. 

Here are some of our favorite 600W HPS lights on the market as of now: 

Lastly, 1000W HPS lights run 1000 watts per hour. Also, you need to have a minimum of 1100W of electricity supply. The power consumption and requirement of 1000W HPS is the highest.

Summary: 1000W HPS requires and consumes the most electricity. Then comes 600W HPS and 400 HPS respectively.

Coverage Area

Each wattage of HPS light can cover area sizes. For indoor hemp growing, the coverage area is particularly important. That way, you can set up your indoor farm.

The coverage area of 400W HPS lights is 3 square meters. You can easily grow 1-3 plants using 400W HPS lights.

However, 600W HPS lights cover more area than 400W HPS lights. The coverage area of 600W HPS lights is 3.34 square meters. You can even grow more plants than 400W HPS at 4-5 plants.

Nevertheless, the 1000W again overrules the other two lights. It consumes the most electricity and also covers the most area. The coverage area of 1000W HPS lights is 4.55 square meters. You can easily grow 6-8 plants using 1000W HPS lights.

Summary: 1000W HPS covers the most area and grows the most hemp plants. Then comes 600W HPS and 400W HPS.

Light Output

Every plant needs lights to produce energy and grow. The prime source of light is the sun. 

However, to grow indoor hemp the light source is the HPS light. So, knowing the light output or illumination of each HPS light is important.

The light output of 400W HPS is 50,000 lumens. It is bright enough for plants to grow effectively.

Albeit, 600W tops off 400W with 90,000 lumens light output. 

However, 1000W HPS has a light output ranging between 120,000 and 145,000 lumens. Which means it produces the brightest light. Here are some of our favorite 1000W HPS grow lights on the market as of now:

So if you’re looking for super bright lights then get the 1000W HPS grow lights.

Summary: 1000W has the brightest light. Then comes 600W and 400W HPS respectively.


HPS light tends to get hot. So does the environment. Heat can be a necessary evil for your hemp. Because not enough heat will slow down the hemp growth. Also, too much heat can destroy the hemp plants. So, let’s talk about the temperature of each HPS.

400W HPS remains at a stable temperature throughout the operation. Because it uses low wattage to illuminate and also is the least bright. So, growing small numbers of plants under 400W HPS can be effective.

Source: bbier.com

However, 600W tends to get hotter than 400W HPS. Still, the temperature will be well under the limit of the required room temperature. So, it is also a safe option for many as you can see-

Lastly, 1000W tends to get very hot over time. This can cause your hemp to be ruined. So, proper air ventilation is very necessary if you set up 1000W HPS. 

Here are some ventilation systems that we’ve used to grow hemp along with the 1000W HPS: 

Now if you don’t want your grow tent to be too hot then get the 600W or the 400W HPS.

Summary: 400W HPS is the least hot. Then comes 600W and 1000W HPS.


Finally, let’s talk about the cost. Whatever HPS light you need should be within your price range. So, let’s compare the price of each HPS light.

The cost of a 400W HPS bulb is not more than $15. Yet, there are many options out there on the market.

However, keep in mind that some tend to be of inferior quality. So try to choose a good quality one. Here are some of our tried and tested 400W HPS:

Nevertheless, 600W HPS bulbs cost slightly more than 400W HPS bulbs. However, well within $20, you can find HPS bulbs. 

Now, 1000W HPS bulbs will cost more than $30. This is the most expensive compared to 400W and 600W. 

Summary: 1000W HPS is the most expensive. Then comes 600W HPS and 400W HPS.

That’s all regarding the head-to-head comparison. Make sure you properly follow ways to grow hemp indoors.

Now, let’s move on to the next section.

So, Which Light is Better for Your Indoor Grows?

The HPS light you choose has to cover many criteria. According to those criteria, we will give our thoughts. Here’s a table that summarises everything regarding this debate:

400W and 600W HPS lights are good for small numbers of hemp plants. Also, the lights don’t get hot so you can keep them closer.

However, for the large quantities of hemp plants, you need 1000W. Otherwise, taking this will be a waste of time.

Whatever you choose, consider hemp plants’ quantities first.


How Long Does Hemp Need to Completely Mature?

Hemp takes 90-120 days to mature from seed to plant. The buds bloom once more before withering off in preparation for the next hemp batch. Hemp is an annual plant, unlike vegetation that comes and goes each year. So, you can grow a maximum of 2 batches each year. Also, you need to take care of hemp.

What Are The Benefits of Indoor Hemp Cultivation?

There are many benefits of indoor hemp cultivation. You can grow hemp in a small space. Also, you don’t need to change soil over and over again to grow hemp. In addition, hemp fertilizes the soil and makes it strong. Furthermore, Hemp’s seed, oil, and fiber have thousands of uses on the market.

What’s The Difference Between Hemp Grown Indoors and Hemp Grown Outdoors?

The main difference is hemp grown indoors has higher cannabinoids than outdoor-grown hemp. However, you can grow more hemp outdoor than indoors. Also, indoor hemp requires artificial light and water supply. But with outdoor hemp, you don’t need artificial light and a continuous supply of water.


That’s all regarding the 400W vs 600W vs 1000W HPS. Hopefully, you can choose the right option for yourself after going through the article.

Here’s a tip, increase the humidity of the room for hemp plants. That way, your plants will be fresh and nutritious.

Have a good day!

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