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Making Indoor Cannabis Cultivation More Efficient

By Matt Walstatter

One of my least favorite parts of being an indoor cannabis grower is the obnoxious amount of power that we use. Of course, the obvious solution to this conundrum is to move outdoors or into greenhouses.

While I believe that sun-grown cannabis represents the future, both for Pure Green in particular and the industry at large, it is not quite that simple. Personally, I prefer indoor cannabis, as do most of Pure Green’s customers.

As long as the demand for indoor remains substantial, people will produce indoors.

So while we are looking at expanding into sun-grown cannabis in the next few years, I also see tremendous value in working to make indoor cannabis cultivation more energy-efficient and less wasteful of water.

Fortunately, the progressive legalization and normalization of cannabis has spurred significant research and development of new, more efficient technologies for indoor agriculture. A savvy grower can use these technologies to save power, water and significant sums of money over time.

Today, I’m going to talk about some lighting technologies that can save substantial amounts of power. Next time, I’ll get into some other ways for indoor growers to reduce their environmental footprints.


Lighting accounts for the majority of the power consumed by indoor cultivation, which also means it offers the greatest opportunities for energy savings. Since the dawn of indoor cannabis cultivation, high pressure sodium lamps have been the industry standard. These fixtures come in a variety of sizes, with the overwhelming majority of growers choosing 1,000 watt bulbs.

These HPS lamps are highly effective for cannabis cultivation, but they use a significant amount of power. Until recently, no other affordable options could produce comparable quality and yield, but recent advances in lighting technology have opened up a great deal of possibility.

LED (light emitting diode) lights offer perhaps the greatest potential for energy savings. This technology has been around for more than 50 years, but only through recent advances have LEDs become viable for indoor agriculture.

A typical LED fixture uses about 330 watts, but each is designed to replace a 1,000 watt HPS light. Light emitting diode’s create significantly less heat than HPS, which allows a grower to save on both the power and equipment needed for HVAC (heating, ventilating, and air conditioning. The lower temperature also means that the lights can sit closer to the canopy. And, LED bulbs can last 10-20 times longer than HPS bulbs.

There remain some pretty significant concerns about LEDs.

First of all, they are very expensive. They can cost 3-4 times as much as the HPS fixture that they will replace.  The good news is that while the cost is greater up front, the power savings that comes from running LEDs should offset the additional expense in 1-3 years, depending on individual circumstances.

The larger problem with LEDs involves concerns about both the quality and quantity of cannabis that they produce. I know a couple of growers who are completely content with their LED setups, but most growers that I have talked to feel that the technology isn’t quite there yet.

Quality is less of an issue, although it remains a concern for some. There is even some evidence that the ability to fine tune the light spectrum that your plants receive under LEDs can actually help to optimize terpene and cannabinoid production, although many growers still feel that they get better quality under a traditional HPS.

Yield, however, remains an issue. One grower that I spoke to in my research ran a side by side comparison of LED vs. HPS, with all other variables remaining identical. The LED room yielded less than 50 percent of what the HPS room produced.

The general consensus seems to be that most LED technology is not quite ready for prime time. I have heard from several people I trust that most of this technology is 3-5 years from really being ready. But, I do know a few people who are thrilled with their LEDs, so I encourage you to do some research on your own.


Another promising technology is called LEC, or light emitting ceramic. These lights are also known as ceramic metal halide.  Many growers use these lights for vegetative growth, and an increasing number have begun to use them for flowering as well.

Growers have begun to replace 1,000 watt HPS lamps with 630 watt LECs, with comparable yields and quality. In fact, many growers I have spoken to feel that they produce superior product under LECs. One even presented a stack of terpene profiles to show that the LEC-grown cannabis contained more terpenes.

While the LECs are more expensive up front, they can reduce the power needed for lighting and HVAC by as much as 40 percent. Because they produce less heat, growers using LECs need to purchase less HVAC equipment up front, savings that can offset the additional lighting costs.

Next time, we’ll look at some tips to save water. We’ll also discuss some examples of regulatory and structural changes to the industry that can result in improved energy efficiency. I’ll also tell you about some organizations working to help growers save power and water.

Matt Walstatter

Matt Walstatter

Matt Walstatter and his wife, Meghan, are the owners of Pure Green, a patient owned and operated dispensary in Portland, Oregon. They have jointly owned and operated cultivation centers since 2001. Their dispensary opened in 2013. Matt can be reached at (971) 242-8561 or [email protected]

This Post Has 4 Comments
  1. Nice Matt … As with your outlook our experience with levels of productivity still tip the scales in favor of the HPS lamps (DE) but find that using a room with an efficient HVAC system (in our case Stulz … Clean room qualified efficient gear) we expect our power footprint for the cultivation operation to perform in the $60 per pound cost range all in noting our latest indoor innovations are getting between 3.5 and 4 lbs per light based upon a five harvest cycle covering 20 different strains. We agree that LED’s will certainly develop over time to match the HPS performance metrics.

  2. People will be quick to accept greenhouse grown when they seeing the quality that results from doing it right. Anyone can have a basement and a light and call it an indoor grow, and we all know it takes a lot more than that. Right now, greenhouse grown can come from a few pieces of pvc and some plastic with little control or quality. That’s changing quickly. High-efficiency greenhouses produce consistent results that don’t sacrifice quality!

  3. Nice article, however what about all the power draw from AC and Dehumidifiers, etc. What if there was a machine that provides ALL of your power, without CO2 emissions or fossil fuel usage, and costs less per Kilowatt / Hour for power than grid power over the life of the machine? This Hybrid Generator will take you 100% off grid, wherever your operation is located. You-Gen Hybrid Generator is the solution in 60kwh increments. Contact me for more information.
    Aaron Turner
    [email protected]

  4. Nice article but your LED information is not current. The story of lost yields with LED is probably related to the wattage you mentioned to replace 1000W HPS of 330W. If you use µmol/J as a measurement of efficiency you can accurately compare technologies in an accurate manner. Therefore, the most efficient LEDs will require at least 585W-660W to equal 1000W HPS on a one-for-one basis. The “black-eye” of the LED industry can be accredited to false equivalencies like this one. You will lose half your yield if you are only providing half the light. We implement LED lighting in production environments that regularly get 20-40% yield increases over HPS, triple digit percentage terpene increases and consistent cannabinoid profiles amongst both technologies.
    Ryan Ryall – Horticultural Lighting Consultant
    Ryall Grow, LLC – [email protected]

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