Welcome to our annual list of the best HPS grow lights for your grow room! As one of the most trusted voices in indoor growing, we're often asked, "What's the best HPS grow light for my plants?"

The truth is, finding the perfect light for your plants depends on your budget, the size of your growing area, your skill level, and most important, the intensity and coverage your indoor garden requires.

That's why we've put together this list of the top 10 HPS grow lights of the year based on their power, affordability, and versatility. Combining our expert testing, customer feedback, overall build quality, and plant count, we present you with the best HPS grow lights to fit any budget and any garden.

1. Editor's Choice

$239.95 ⭐⭐⭐⭐⭐ (63 Reviews)

600W HPS+MH Air Cool Hood Grow Light Kit

This 600w grow light is a staple of any grow room, whether you're a first-timer or you're growing your hundredth grow.

With 90,000 lumens, 5500k MH spectrums, and 2100k HPS spectrums this grow light gives you optimal intensity and wavelengths to grow 6 plants from seed to harvest. To that, its dimmable ballast can reduce intensity by up to 50% while plants are young and increase peak intensity by 10% toward harvest for a truly tailored experience.

And with multiple focal points, a domed design, and air cooled capabilities, this grow light maximizes intensity onto 16sqft. canopies while reducing heat.

Control light intensity from 50%-110%

Connects to exhaust fans to reduce grow room heat

Peak PAR: 900 (HPS), 602 (MH)

Peak Lumen Output: 90,000 (HPS), 61,000 (MH)

Covers 4-6 Plants

2. Coolest Running 1000w Light

1000w HPS and MH Air Cool Hood Grow Light

$259.95 ⭐⭐⭐⭐⭐ (22 Reviews)

100W HPS+MH Air Cool Hood Grow Light Kit

This 1000w grow light gives you all that and lasting power. With a peak output of 130,000 lumens, this grow light will give you at least 8-9 grow cycles of intense light.

The hood reflector connects to your ventilation system and cools your bulbs to reduce wear for longer lasting intensity. Paired with the tempered glass shield, this reflector also helps trap and remove heat to lower its impact on your plants.

Its dome shape and multiple focal points give helps spread its peak PAR of 1300 PPFD across a 16sqft. footprint. So if you need a grow light with enough for up to 8 plants and want to avoid overheating your plants, this is the kit you need.

Cools bulbs for maximum longevity and intensity

Reduces heat to stabilize grow room environment

Peak PAR: 1,377 (HPS), 907 (MH)

Peak Lumen Output: 130,000 (HPS), 110,000 (MH)

Covers 6-8 Plants

3. Perfect for Covert Growing

400w HPS and MH Air Cool Tube Grow Light

$189.95 ⭐⭐⭐⭐ (9 Reviews)

400w HPS+MH Air Cool Tube Grow Light Kit

This grow light is perfect for lighting space-saving grows like closets, small grow tents, and anywhere you need to keep plants thriving without being seen.

Its 25x6" reflector utilizes air cooled vents to keep optimal environmental conditions in compact, covert spaces. With a peak output of 55,000 lumens and a 2x4ft coverage area, this grow light has enough intense light to grow 2-4 plants.

The digital dimming ballast helps you dial in light intensity from seed to harvest in any compact growing area. So if you've got to keep your plants out of site but still well lit, make sure to grow with this kit.

Great for spaces as small as 2x2ft

Cool tube reduces heat output for stable environment

Peak PAR: 534 (HPS), 416 (MH)

Peak Lumen Output: 55,000 (HPS), 36,000 (MH)

Covers 2-4 Plants

4. High Intensity, Low Cost

1000w HPS Wing Reflector Grow Light

$189.95 ⭐⭐⭐⭐⭐ (23 Reviews)

1000w HPS Wing Reflector Grow Light Kit

This 1000w grow light kit is one of the only ones to give you a wide, intense coverage area without sacrificing intensity, and do so at a cost-effective price.

The wing reflector offers multiple focal points to spread across across an 8-10sqft growing area. With a peak PPFD of 1377, you get more than enough light to grow up to 8 plants evenly, compared to other reflectors that leave plants on the outer edges of your garden with less than 50% peak PPFD.

So if you've got lots of plants to grow but you're working on a budget, this is the most cost-friendly and effective 1000w grow light you'll find.

Extra large wing reflector helps spread light evenly across canopy

Easy to assembly, easier to use

Peak PAR: 1,377

Peak Lumen Output: 130,000 (HPS), 110,000 (MH)

Covers up to 8 Plants

5. Widest Coverage Area

1000w HPS and MH Cool Tube Hood Grow Light

$259.95 ⭐⭐⭐⭐ (4 Reviews)

1000w HPS+MH Cool Tube Hood Grow Light Kit

If you have a large canopy to cover, this 1000w HPS grow light has the intensity and footprint your plants need to thrive.

Its hooded shape helps direct light downward down onto plants for maximum intensity, while extra large size has help spread light across a 5x5-6x6ft canopy. With a peak intensity of over 125,000 lumens, this grow light pumps out intense light without sacrificing coverage area.

With air cooling capabilities, this light will keep your plants thriving without overwhelming them with heat. So whether you're going lots smaller plants or a few large plants, this is the light you need to keep 6-8 plants thriving.

The best features of XL hoods and cool tubes

Extra large hood covers 25-36sqft.

Peak PAR: 1,377 (HPS), 907 (MH)

Peak Lumen Output: 130,000 (HPS), 110,000 (MH)

Covers 6-8 Plants

6. Strongest Coverage

1000w Double-Ended Cool Hood Grow Light

$325.95 ⭐⭐⭐⭐⭐ (18 Reviews)

1000W Double Ended Cool Hood Grow Light

This double-ended grow light give your plants 10% more intensity than their single ended counterparts, making them perfect for up 6-8 tall plants. Add that to the super lumens on each ballast, and you're looking at nearly 20% brightness over standard bulbs!

With a peak lumen output of 159,200 lumens and with a peak PPFD of 1776, this light will penetrate canopies deeper than any other 1000w grow light. With a collapsible glass lens and 6" vent ports for better ventilation than other cool hoods.

So if you're looking for extra strong, deep penetrating light coverage, this is the grow light you need.

The most intense cool hood on the market

Deepest leaf penetration in its class

Peak PAR: 1,776 (HPS), 1,222 (MH)

Peak Lumen Output: 159,200 (HPS), 85,200 (MH)

Covers 6-8 Plants

7. Best Beginner Grow Light

400w HPS and MH Wing Reflector Grow Light

$169.95 ⭐⭐⭐⭐⭐ (75 Reviews)

400W HPS+MH Wing Reflector Grow Light Kit

This 400w grow light will give you the optimal lighting you need to make sure your first harvests are flavorful ones.

This kit's equipped with HPS and MH bulbs that give you 360000-55000 lumens of light, enough light for 2-3 plants to thrive. The extra large 20x20in. wing reflector, and you get an 9sqft. light footprint for your favorite flowers, veggies, and herbs.

You can also give your plants a 5-10% boost of intensity via the on-board super lumens setting on your ballast. So if you're just starting with your first indoor plant, this is the perfect HPS grow light to work with.

Optimal spectrums and intensity for first-timer's

Easy to assemble, simple to use

Peak PAR: 55,000 (HPS), 36,000 (MH)

Peak Lumen Output: 534 (HPS), 416 (MH)

Covers up to 3 Plants

8. Strongest Compact Grow Light

1000w Double-Ended Grow Light Complete

$299.95 ⭐⭐⭐⭐ (2 Reviews)

1000W Double Ended Complete Grow Light Kit

When you need professional levels of light coverage but don't have the room for pro-size reflectors, this grow light will get the job done.

Its electronic ballast on this light gives you 15% extra intensity. During super lumen, you get a peak lumen output of 183,000 and peak PPFD of over 2,000. That's enough deep penetrating light to grow up to 8 tall plants over a 16sqft. canopy.

Its compact design eliminates the need to mount an external ballast, making it the most compact and easiest grow light to install and use.

15% Super Lumen feature

All-in-one design is the most compact in its class

Peak PAR: 1,776 (HPS)

Peak Lumen Output: 159,200 (HPS)

Covers up to 8 plants

9. Great Value

600w HPS and MH Wing Reflector Grow Light Kit

$189.95 ⭐⭐⭐⭐⭐ (58 Reviews)

600W HPS+MH Wing Reflector Grow Light Kit

When you're ready to grow but don't need any extras or features you won't use, this is the light you need.

You get 61,000-90,000 lumens of light to cover a 16 sqft. canopy without any complicated, decked-out reflectors. In fact, the 20x20" extra large wing reflector focuses and spreads a max PAR of 900 PPFD across a 4x4ft area. Best of all, the digital ballast can adjust lumen output from 50% to 110%, giving you full control over your light output.

So if you're looking for the same powerful coverage as any other 600w without all the pricey bells and whistles, this is the grow light for you.

Cost-effective design with vital components and features

Lightweight, easy-to-assemble design

Peak PAR: 900 (HPS), 602 (MH)

Peak Lumen Output: 90,000 (HPS), 61,000 (MH)

Covers 4-6 Plants

10. Huge Power in Tight Spaces

1000w HPS Cool Tube Grow Light Kit

$219.95 ⭐⭐⭐⭐⭐ (14 Reviews)

1000w HPS Cool Tube Grow Light Kit

When you're looking for a high-powered light but don't have the room for a bulky hood or wing reflector, this is the grow light you need.

This grow light is slim enough to fit in growing spaces as small at 2x4ft but strong enough to cover 25sqft. canopies. With 130,000 lumens and a peak PAR of 1377 PPFD, this light is bright enough to cover at least 4-6 regular-sized plants with the penetrative power to help 2-3 taller plants thrive all the way down to the bottom branches.

So when you're in need of a compact light for your not-so-compact plants, this is the grow light you're looking for.

Air cool design keeps tight spaces as cool as possible

Perfect for tall and bushy plants alike

Peak PAR: 1,377 (HPS)

Peak Lumen Output: 130,000 (HPS)

Covers 6-8 Plants

What is an HPS Grow Light?

HPS (high pressure sodium) grow lights are one type of HID (high intensity discharge) light used to grow plants. HID lights are all filled with gas that emits light when heated.

  • HPS bulbs generally contain sodium, mercury, and xenon. These chemicals are held inside what’s called an arc tube.
    • The bulb is powered by a ballast that ignites the gas by sending energy through the arc tube.
    • This energy is expressed in light and heat energy.

If you're wondering what "HPS" refers to, it speaks to the wavelengths of light these bulbs give off.

  • HPS grow lights have lots of red, orange, and yellow wavelengths in their spectrum which stimulates root and flower growth. This makes them an ideal grow light option for flowering plants.
  • HPS lights offer some blue light which helps branch and leaf growth. That also makes them helpful during the clone and vegging stages of growth, too (though they're not as effective as MH bulbs with vegging).

Benefits of Using HPS Grow Lights

So why should you use an HPS grow light as opposed to all the other types of grow lights on the market? There are a number of benefits to these lights that make them the best choice:

They Mimic Natural Light: Plants thrive when they have the wavelengths and strength closest to their natural amount. HPS grow lights are the best at doing just that, and their light contains a spectrum almost identical to the sun. Combined with the strength of a given ballast, a plant will receive optimal amounts of light to grow- sometimes better than it would in nature.

They’re Powerful and Effective: One of the biggest benefits of HPS grow lights is their high potential for light output. A 1000w HPS bulb, for example, gives off 130,000 lumens of light at 1150 PPFD, compared to other forms of lighting that offer far less lumen output. That means you can grow a wider variety of plants than you would with other grow lights.

They’re Affordable: For starters, HPS bulbs are as affordable as grow lights come, and you’re not sacrificing any quality for the price! Plus, if one part of your HPS light system fails, it’s easy and cost-efficient to replace as opposed to having to buy a whole new system.

They’re Adjustable: Most HPS lights have dimmable ballasts. This makes it easy to control the intensity of light your plants are getting to ensure optimal intensity.

Flexibility: There are a lot of different types of reflectors to give you the light that your plant and spatial needs. No matter if you need tons of light for lots of plants or a little bit for a few, there's an HPS grow light to suit any indoor garden and gardener.

The Importance of Lumens and PAR

The key to ensuring you give your plants optimal lighting, it's important to understand PAR and lumens. These two terms refer to the intensity and brightness of a grow light, and only the right about of each will help your plants grow, so let's take a look at what these terms mean:

Lumens

Grow Light Lumen Output

Lumens measure the amount of light that a light source (like a grow light bulb) emits per second, or it's "brightness". This light emitted by a source is called its luminous flux (if you want to get really technical), and it’s the light power perceived by the human eye. There are wavelengths of light that we cannot see, but lumens measure what we can.

If your head, don’t worry. All you really need to know are two things:

  • The more lumens a grow light emits, the brighter it is.
  • Fewer lumens means you'll get a dimmer light.

Optimal lumens vary from plant to plant, but generally, these are the necessary lumens for successful plant growth.

  • 2,000 to 3,000 lumens per square foot are ideal for the vegging stage when plants begin going through photosynthesis.
    • Note: 2,000 lumens per square foot are the bare minimum of what you'd want for plants that require very minimal light intensity.
  • 7,000 to 7,500 lumens per square foot make up the ideal measurement for most grow rooms.
  • 5,000 to 10,000 lumens per square foot will be necessary during the flowering stage when your plants are producing fruit.

PAR

Grow Light PAR Output Chart

PAR (measured in PPFD) is a measurement of how intense a light is, or its "penetration". A grow light's intensity is an indication of the potential for that light to penetrate leaves in order to perform photosynthesis and grow.

  • Without enough PPFD you'll find that plants are light-deprived if they start to grow upward and their stems begin to stretch rapidly. This means they’re reaching for light.
  • Too much PPFD means your plants are getting too much light. If your grow lights are too intense, you may run into issues like light burn, light bleaching, and overall stunted growth.

Each plant is unique and will require a different amount and intensity of light based on its specific needs. The key to ensuring you get the light best for your plants is to research the plant you want to grow.

  • 250 to 500 PPFD is needed for clones and seedlings up to vegging plants.
  • 600 to 800 PPFD is generally used for flowering and fruiting plants.
  • 900 to 1000+ PPFD is usually too intense for plants, though with the correct CO2 regulation you would be able to utilize that light for fruiting plants

Grow Light Spectrum

Grow light spectrum for vegging and flowering stages.It’s important to also consider the light spectrum of certain grow bulbs and the spectrum your plants will need in order to thrive when picking out a grow light.

  • Flowering and fruiting plants work best with warmer, red light, which is closer to light from the sun during the fall and winter.
  • Meanwhile, a wavelength with blue light is more ideal for vegging plants that need that whiter spring/summer light.

As previously mentioned, different types of grow bulbs give off different spectrums depending on what sort of chemicals they contain. Two main types of HID bulbs are HPS and MH.

  • HPS grow lights give off a red/orange glow. The warmer wavelengths of HPS lights make them an especially good option for plants that are in the flowering stage.
  • MH grow lights give off more blue and white light. These cooler wavelengths make MH lights ideal for plants in the vegging stage.
  • Most plants will need the wavelengths from HPS and MH spectrums to thrive, so it's a good idea to consider using both. However, as we've mentioned, HPS bulbs have enough blue in them to help young and vegging plants grow into the flowering stage.

Optimal Light Footprint aka Light Coverage

Indoor Grow Room with HPS Grow LightAnother vital factor to finding the right grow light for your needs figuring out exactly how large the area you’ll need to cover. Contrary to popular thinking, though, it's a better idea to consider canopy coverage rather than entire grow room coverage. That's what we'll be doing here.

Canopy coverage refers specifically to the light that will be spread across the plants in your grow room or grow tent. This ensures you get lights that provided the actual coverage your plants need for a successful grow.

There are two key factors to getting the ideal grow light footprint:

  1. Figure out the size your canopy will be. The size of the canopy will be what your footprint needs to cover. The top canopy refers to that layer of leaves at the top of your plants, and will depend on how many plants you want to grow and your desired size.
  2. Decide how high you want to position your grow lights. The higher up you position the lights over your canopy, the wider the footprint will be. Just remember that the farther away your lights are, the weaker the light will be once it reaches your plants.
    • For most plants, the minimum height requirement is usually around 12 inches above your plants.
    • Depending on what you're growing or the stage of growth your plants are in, though, that requirement could increase to 24 to 36 inches.

It’s important to keep in mind that over time, your plants are going to get larger than their initial size. This means the size of your canopy will also increase over time, so you should make sure to consider this when determining how many plants you’re going to grow and the footprint you’ll need to cover them.

When picking a grow light, keep this tip in mind: You’ll need to find a plant light with the right combination of footprint and intensity.

HPS Grow Light Reflectors

The next vital aspect to consider are your reflector. Grow light reflectors help direct, spread, and intensify the light coming from an HPS bulb onto your plants. Reflectors are what help provide ideal coverage out of your grow lights, and they come in many shapes and sizes to ensure that you’re getting the coverage you want for your plants. Let's take a look at the most common reflectors you'll be using:

Winged Reflectors

HID Grow Light Wing Reflector

Wing reflectors help spread light across your canopy. They have a bat-wing shape with different reflected points to optimize spread and intensity without overwhelming plants.

Hood Reflectors

HID Grow Light Hood Reflector

Hood reflectors have a domed shape that offers a great amount of intense light in a distinct, confined footprint. This footprint has the most intense of all reflectors.

Cool Tube Reflectors

HID Grow Light Cool Tube Reflector

Air-cooled reflectors offer the ability to limit the amount of heat they emit by running air through the reflector, past the bulb, and pushing hot air away from your garden.

Single-Ended vs. Double-Ended HPS Grow Lights

The last decision you'll make when it comes to choosing your HPS grow light is whether you're want to use a single-ended HPS grow light or a double-ended HPS grow light. Each offer their own unique advantages to your grow room, so let's take a look at how each will benefit your grow room:

Single Ended Grow Lights

Single-Ended Grow Light

Single-ended HPS bulbs are a lot like your typical, Edison-style light bulb: They screw into a single-ended socket, known as a Mogul base. These bulbs are long and wide. The base of the bulb connects to the arc tube and is held up on each end by a metal frame wire.

Single-Ended Bulbs Run Cooler: Single-ended HPS bulbs run significantly cooler than double-ended lights because they take less energy to power. That means they won't add as much heat to your grow room as a double ended would just to get the light your plants need.

Single-Ended Have More Manageable Intensity: Single-ended HPS bulbs give off much gentler light than double-ended's which means you won't need to raise your lights over 24" to avoid burning like you would otherwise. This saves space in your grow room and helps avoid stretching of plants.

Conclusion: Single ended HPS grow lights are perfect for all growers, whether they're beginners growing a couple plants or a pro growing a lot of them.

Double Ended Grow Lights

Double-Ended Grow Light

Double-ended HPS bulbs function more similarly to fluorescent tube bulbs. The arc tube is supported by two small wires that fasten into the reflector’s two sockets. They’re also much thinner than single-ended bulbs because they have no frame wire to take up space inside.

Double-Ended Bulbs Crank Out Intensity: Overall, double-ended HPS lights provide 10-15% more power than their single-ended counterparts, resulting in more intensity than single ended grow lights. That intensity helps tall plants get the light they need further down than single-ended's can.

Double-Ended HPS Light Distribution: On top of all the power they offer, double-ended HPS bulbs typically offer a larger coverage area. This is especially helpful for gardens with large bushy canopies or grow rooms with lots of foliage to cover.

Conclusion: Double ended HPS grow lights are perfect for growers who want to grow tall plants, need to cover large canopies, and experienced growers looking to push their yields to the limit.

What's the best HPS grow light for you?

From closet grows to larger operations, HPS lights are an excellent choice when it comes to producing quality harvests. All you have to do is find the best one to suit your needs. And with the knowledge you've gained in this article, you'll be able to navigate through all of the sales pitches to find the grow light that's truly the best one for your plants. Just keep two pieces of info in mind:

  1. Always make sure you’re giving your plants the right amount of lumens, as well as the proper wavelengths of light for them to thrive in.
  2. be sure you use a grow light reflector that’s a good fit for your grow room.

Do that, and you'll find your perfect grow light in no time. Of course, you can't go wrong with any of the top 10 we've listed, either. So what are you waiting for? Go find the HPS grow light you need to start pumping out the yields you've always wanted.

What Makes Growace Different?

  1. We provide the best support and customer service in the industry. Whether you're just getting started or you've been growing for some time, you'll notice that most shops end your relationship at checkout. Our in-person and virtual grow experts will help you choose the best equipment for your needs, get your grow room running, and give you the knowledge to keep your plants happy from seed to harvest.
  2. We offer everything your plants need for maximum growth. On top of offering the highest value HPS grow lights in the industry, we offer everything else your plants need to reach their full harvest potential. From grow tents to ventilation, nutrition to mediums, down to measuring tools and training accessories, we're your one-stop shop for everything in the grow room.
  3. We offer the best warranty on HPS grow lights. When it comes to warranties, we offer coverage that's beyond compare. In fact, each Yield Lab HPS grow light has a 3-year exchange warranty on ballasts, a 1-year exchange warranty on HPS grow bulbs and reflectors, and each come with our 120 Day Satisfaction Guarantee to ensure you have the best experience growing from the moment you receive your light.

What do our Customers Have to Say?

HID grow light setup in grow tent.
HPS grow light setup in grow tent.
HPS grow light in grow tent.
HPS grow light used for growing plants in a grow tent.
Growing tomatoes in an indoor grow tent.
Plants growing in an indoor grow tent.
Growing plants in a grow tent.
Indoor grow tent op with an HID grow light.

⭐ "Simply amazing." - Brian

Bought this and used it through a whole grow. All I can say is simply amazing. Works like a charm very quiet, runs very cool and I can't say enough about the construction and quality. Very heavy duty. Also the hangers are great they work like a charm.

⭐ "This is a really nice grow light system." - Lodus

I've been growing for 25 years. I've outdoor gardens, but I've mostly grown indoors and have had several setups. This one is especially nice, though! The ballast is quiet, and the adjustable hangers make positioning the light distance from the plants a breeze. Perfect for a 5x5 grow area and 4 plants.

⭐ "Highly recommended." - Camron

Ever since I hooked it up and set it over my garden, all my plants look strong and healthy and ALIVE. When ever the lights are on my babies are standing up proud and strong, I definitely recommend this ( if you have a small garden).

⭐ "Great versatility." - Steven

This light performs very well. I really like the dimmable feature. It's like having the versatility of having a 1000w, 600w, or 400w without having to buy different bulbs and ballasts.

Frequently Asked Questions

Q: What's the best size HPS grow light?
A: The best size HPS grow light is the wattage that gives your plants the lumen and PAR (PPFD) they need to thrive. So the first key to unlocking the optimal size grow light for your plants is finding the optimal PAR and Lumens for your plants (note: most plants need 50-70 PPFD per sqft., but it's safe to make sure you know the right levels for your plants).

After you know how the intensity your plants need, you'll want to find a light that'll give you the PAR you want. Most HPS grow lights- like those from Yield Lab- will offer PAR charts that show you the PPFD at all points of a light's footprint. Read the charts and find the light with the coverage you need within the area you'll be growing plants. For example, if your plants will need a max PPFD of 1050 like most flowering plants, you'll want to go with something in the 600w range or higher.

It's important to keep in mind that PAR requirements will vary as your plants grow. Make sure your light can reduce/increase PAR as needed for optimal growth.

Q: How much heat do HPS grow lights produce?

A: HPS grow lights operate at around 5400°F, and thankfully most of that heat is infrared. However, the energy that comes off of your bulb is in the form of heat temperature, and there's lots of it the stronger your light is.

The heat energy given off by bulbs won't raise your grow room's temperature significantly, but in enclosed growing areas with poor ventilation, that energy can become a problem. That heat will build up and throw off your grow room's environment, raising temperatures and humidity levels. That's why it's important that no matter what size HPS grow light you choose, your growing area has optimal airflow and ventilation.

Q: How do I put an HPS grow light together?

A: Thankfully assembling an HPS grow light together is simple. It's essentially done in 5 steps:

  1. Assemble your reflector.
  2. Install the grow bulb (HPS or MH) into the reflector.
  3. Hang your reflector above your plants.
  4. Connect your reflector to the ballast.
  5. Connect the ballast to the power source and turn on on the ballast.

In fact, to see a full demonstration on setting up and running our Editor's Choice grow light, check out our video review below:

Q: How much does it cost to run an HPS grow light?

A: The cost of running an HPS grow light can be calculated by taking your energy provider's rates (KWH), factoring in the wattage light you'll be using, and multiplying that by the number of days in the month. Don't worry, it's a lot easier than you'd think- here's an example:

  • First, let's establish that rates are measured in KWH, which is 1000w's per hour.
  • Now let's take a light, like a 600w grow light, and figure out how much power it will use in one hour. To do that, simply divide 600 by 1000, which is .6, which means in 1 hour, your light will have consumed .6KW.
  • Next, you'll want to multiply that number by the number of hours you'll be using your light. Let's say you're vegging: that means you're running for 16 hours each day. So take 16 x .6 and you'll find 9.6, which means you're using 9.6KW of power a day.
  • Take that number and multiply it by your rates. Let's say you'll be charge an average of $0.26/KWH. Take 9.6 x .26, and you'll get an estimated daily cost of about $2.50.
  • Last, take that daily rate and multiply it by the days in the month, and you'll have a rough estimate of what you'll be paying per month. In this case, 2.50 x 30 would be an estimated monthly bill of $75.

For an in-depth look at calculating your monthly electric bill, click here to read our article and figure out your energy budget.

Q: How long do I leave my HPS grow light on each day?

A: The length of time you leave your grow light on each day depends on the stage of growth your plants are in. Most plants are phototropic plants, which means they rely on light to tell them how to grow. That's why you'll be leaving your lights on at various durations depending on the stage of growth you're at:

  • During the seedling and clone stage, most growers leave lights on 16-24 hours a day, with 0-8 hours of darkness.
  • During the vegging stage of growth, growers will leave lights on for 16 hours with 8 hours of darkness.
  • When plants are flowering and ready for harvest, growers will leave their lights on for only 12 hours a day.
  • Note: for non-phototropic plants (aka auto-flowering plants) you can leave lights on between 12 and 24 hours throughout it's life cycle, as their genetics- not light- trigger flowering.

Q: How high do I hang my HPS grow light over my plants?

A: When it comes to hanging your grow light, it all depends on the strength and intensity of your light. While you'll want to make sure your plants have optimal, intense light across the canopy, you'll also want to ensure that light isn't over/underwhelming them.

  • Too close and your plants will be at risk from overheating, burning, and bleaching.
  • Too far and your plants will stretch, become weak, and not have the intensity they need to grow healthy foliage.

That's why hanging your light at the right height is vital to growth. A general rule is to have your lights anywhere between 12-30in. away from the top of your canopy. However, that will depending on the strength of your lights:

  • 400w HPS grow lights can be 12"-19" away from plants
  • 600w HPS grow lights should be hung 14"-25" away from plants
  • 1000w HPS grow light lights should 16-31" away from plants
  • Note: As plants grow you'll want to make sure to adjust light height accordingly. However, as plants get into the flowering stage they'll need more intensity. That said, in the vegging stage you can keep your lights at 16-30" height above plants, and toward the flowering stage you can keep them at 12-20" above plants.

Q: Are there warranties on HPS grow lights?

A: The great thing about the grow lights we've featured is that they each come with up to 3 years of coverage on top of a 120 Day Satisfaction Guarantee! While most grow shops have a limited, hard to use warranty, we have a two pronged approach to making sure your grow lights run grow after grow:

  • Our 120 Day Satisfaction Guarantee gives you a chance to put our lights to the test, guaranteeing your full satisfaction over an entire grow cycle- or you money back.
  • Each Yield Lab ballast is backed by an industry-leading 3 year warranty, and every bulb and reflector from Yield Lab is backed by a full year warranty.
  • We also offer lifetime grower support online, over the phone, and via our Facebook group. Long after your first harvest with us, we'll be here to give you advice on growing and help you achieve the harvests you're looking for. Just give us a call at (888) 621-0062, email us at support@growace.com, or contact us via online chat, and we'll get you growing like a pro in no time.

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