How to Choose HPS Grow Lights for Growing Cannabis

Also feel free to check out my main page about cannabis grow lights! This page talks just about HPS grow lights while the other page covers all grow lights.

High Pressure Sodium grow lights, or HPS grow lights, are the golden standard in growing cannabis. HPS lights can be used for the entire cannabis grow from seed to harvest (though some growers like to start with Metal Halide or florescent grow lights before the cannabis hits the flowering stage). HPS grow lights also seem to help growers produce the best cannabis yields. However, HPS lights use a lot of energy and produce a lot of heat. These issues can prevent a beginning grower from deciding to use HPS grow lights.

HPS grow lights produce a harsh yellow light. Read the Complete Guide on HPS Grow Lights!Cannabis plants flowering in a grow tent under the harsh yellow light of an HPS

HPS grow lights are extremely well suited for grow areas that have…

  • Cooler temperatures (since HPS lights will heat up an area)
  • Good Ventilation / Strong Airflow
  • More plants (more than 5 plants)
  • At least 5-6 feet of vertical space (up-and-down room) for the plants to grow

HPS grow lights are not as well suited for grow areas that have…

  • Little ventilation or no way to get air in and out through a hole or window
  • Limited vertical space(such as inside a cupboard). Learn about growing cannabis with CFL lights, which are suitable for small grow spaces.

Another consideration when using HPS lights for a grow area that has a natural temperature that is higher than 65 degrees(F) or 18.3 degrees(C), is that you will need to set up some sort of exhaust system to control heat. A simple exhaust system that consists of some tubing/ducting and an exhaust fan will do the trick most of the time. As long as you have a way to get air in and out of the grow area, you’re golden.

Learn how to easily vent out heat from your HPS grow lights

Setting up an HPS system takes careful planning because you generally need to buy more than just the bulb, reflector, and ballast. In most cases, you will need to set up some sort of ventilation system with an HPS grow light, even if it’s as simple as a fan pulling hot air away from the lights and venting that air outside. Many set up simple ducting systems to manage the hot air. Just remember to make your intake hole bigger than your exhaust hole or you may cause your fan to struggle! This is especially important in a small or airtight grow area because the exhaust fan will be working extra hard to get enough air through the intake hole unless the intake hole is bigger than the exhaust hole in size. In general, when setting up your HPS system, you want to set things up so the hot air from the HPS are blown directly out a window or some other escape with as short a path as possible. This will help make the exhaust system more efficient. You may need to set up a carbon odor scrubber to eliminate any smells before they reach outside. More info on buying a carbon odor scrubber to control the smell of cannabis below, or read the carbon scrubber tutorial.

Digital Ballasts vs Magnetic Ballasts

While magnetic ballasts are cheaper, a digital ballast will start up more quickly, run silently, produce less heat, last longer, and even produce more lumens (light) than a magnetic ballast. More light means more yield and digital ballasts can somtimes produce 20-30% more light than a similar bulb on a magnetic ballast. What’s more, a digital ballast may extend the life of your bulbs so you have to buy new bulbs less often. There really is no comparison in quality between a digital and magnetic ballast, the digital ballast is just better. A magnetic ballast can take up to 20 minutes to start up, and tends to run noisy and inefficiently while producing less light and burning through more bulbs. If at all possible, spend the couple of extra bucks and get the digital ballast!

Learn more about using HPS grow lights when growing cannabis.

Get Started Shopping for HPS Grow Lights Today!

I hope the product links below can help get you started so you can see some concrete examples of what sort of cannabis grow lights are recommended. The grow light systems and growing accessories on this list were specifically chosen for quality and effectiveness.

A full grow light system contains a ballast, a reflector/hood, a bulb, cords and plug, and some systems even include the hanging equipment. I personally recommend starting with a full light system that is made to go together as opposed to trying to buy all the pieces separately and put them together. Whenever you are buying from any grow light seller, make sure that they are a reputable seller and not some guy selling lights out of his garage. There’s nothing worse than spending hundreds of dollars for equipment that is broken or doesn’t work properly. When buying from unrespectable sellers, you may run into customer services issues if you need to return something. I personally like because they have a great return policy and will stand behind you, the customer, if there’s a problem with one of their sellers.

Grow Tents

Some growers choose to use a grow tent to be able to better contain and control the heat. You can set a fan to expel hot air directly out of the tent to a window or other vent. Make sure to allow enough vertical (up-and-down) room for the HPS, the plant, and 1-2 feet of extra space that will need to be between the light and the top of the plant when it’s at full height. Remember 60 inches = 5 feet.

Learn about cannabis grow tents

You May Need an Inline Fan with a Carbon Scrubbers to Remove Odors

Learn about carbon scrubbers and removing smells

Read the Complete Guide to HPS Grow Lights!


Return to Top of Page