Greenhouses Are More Efficient For Marijuana Production

Greenhouses Are More Efficient For Marijuana Production


GrowCo builds and finances greenhouses, and leases them to legally licensed cannabis growers in Colorado.

Updated May 28, 2015


Marijuana may well be the next big frontier for greenhouse growers. Cannabis growers and advisors are starting to move production out of the warehouse and into the greenhouse, to benefit from the efficiencies that the sun’s natural light and environmental controls provide.

In Colorado, Tim Beall, chief operating officer of GrowCo, a Denver-based company that builds and finances greenhouses, and then leases them to legally licensed cannabis growers, is helping growers make the transition from indoor growing to an environmentally controlled structure.

It’s a way, he says, to make production more cost-efficient for growers supplying Colorado’s ever-expanding recreational cannabis market. The state’s Marijuana Enforcement Division estimates that residents and visitors 21 and over consumed 130.3 metric tons of marijuana in 2014, with only 77 metric tons supplied by legal producers. However, growers are also subject to high taxes: A combination of state and county taxes in Denver add up to a 29 percent tax rate.

Greenhouse Structures Offer Energy Savings And Production Efficiencies

Beall, a former greenhouse vegetable grower who used to be chief financial officer for Sunblest Farms, Rocky Mountain Growers and Cherry Creek Systems, is well-acclimated to the benefits growing in a controlled environment offer. He says there are three main reasons to take cannabis to the greenhouse: significant energy savings, a much faster rate of plant metabolism and the advantage of natural physics.

The energy savings is the biggest attraction — a greenhouse is going to use only about a quarter of the energy used in a warehouse, he says. In addition to getting natural sunlight for free in a greenhouse, versus using artificial lighting, warehouse growers would save on the high electricity bills they currently incur by running air conditioning units, even in winter, to offset the heat given off by the lights.

“In a greenhouse, though, the only time I would add light is the times of the year when I probably need to heat the greenhouse anyway,” Beall says. “So that light for them is basically worse than 25 percent efficient, because 75 percent is the heat that they end up having to pay for air conditioning to get rid of, whereas in a greenhouse, that light becomes 100 percent efficient to me because I need that heat.”

Photosynthesis is also double in a greenhouse versus indoor facilities, allowing for faster plant growth rate and optimum plant health, Beall says.

“Think of it this way: Your average indoor grower is going to put in 500 to 600 micromoles of light, but in Colorado, we can get up upwards of 1,500 to 2000 micromoles of light in a greenhouse,” Beall says. “Now, can an indoor guy put in 1,500 to 2,000 micromoles of artificial lighting? Sure, but he’s not going to get the same growth rate out of that. Maybe if he put in LED, HPS, metal halide and something else, he’d come close to meeting that full spectrum of the sun. But studies over the years have shown that light from the sun is 30 percent more efficient for photosynthesis than artificial light.”

Humidity is another problem in warehouses, where growers have to run humidifiers, adding to the already high electricity usage. With their flat ceilings and insulated walls and ceilings, warehouses keep in moisture and heat, compared to the high peaks in a greenhouse, which naturally allow hot air to rise. With vents at the top, as in high-peak, open-roof greenhouses, the heat and moisture can easily escape.

“Inside the warehouse, they actually have to grow slower because they are so worried about keeping their humidity low, which means they’re watering less frequently. When you water less frequently, you have to have a much lower fertilizer or EC rate to avoid root burn,” Beall says. “So there’s a whole combination of issues, whereas with greenhouse technology nowadays, compared to the old hoophouses and Quonset huts, the high-roof greenhouses are so much better.”

Cannabis Greenhouse Ranges Are Small But High-Tech

Because the state of Colorado currently mandates the number of plants growers are able to produce, licensed growers are only able to build in two-acre increments to remain most efficient. But the greenhouses are typically expensive, high-tech, high-peak, open-roof greenhouses that are fully automated and environmentally controlled, similar to a hydroponic vegetable facility, Beall says.

GrowCo currently has three greenhouses under construction. One was scheduled to open in March 2015, one in April 2015 and the third in May 2015. To date, GrowCo advises up to 25 growers.

Leave a Reply

Pete Pond says:

Here at Aeroponics Global Initiatives are working with some growers that are growing the Auto Flowering Dwarf plant and because these plants don’t grow very tall we can plant them in our towers. We also have talked to seed and seedling producers. All of this can be done very well in greenhouses and in much less space.

Nice article. When Marijuana was first legalized the majority of licenses were still issued to warehouse growers. This was more comfortable for regulators, and also many of the early adopters were not from the greenhouse industry. Over the course of the year we have seen this shifting globally, and more and more traditional horticultural companies are getting involved. Cannabis is a good crop for greenhouse production, but be careful of assuming all horticultural knowledge transfers. The really successful groups we have been working with are blending traditional greenhouse efficiency with depth of product knowledge.

Steve says:

Sounds to me like a whole bunch of greenhouse manufacturers who would like a piece of the growing structure pie to me. It would be interesting to find out just exactly what these “expert’s” background and motivations are…

These guys are following the leader who has a massive marijuana farm in Pueblo.

Alex white says:

Greenhouse = $1,000/Lb quality B-
Cost per MG of THC = $.05

Alex white says:

$1,000/lb greenhouse costs. $1,200 warehouse costs. Difference in quality or % of THC?

martin white China bay trading inc. says:

Alex white please send me your best production support research materials? [email protected].
Hands on research in colorado in greenhouses.. only practise innovation time will tell.

Alex white says:

You’re in the business. You know its $1,000/lb for greenhouse and a B- product. What research are you seeking?

Alex white says:

Btw, it’s the milligrams of THC (and others) that matter for grow-value. Indoor grown is worth more than greenhouse based on the percent of active cannabinoids.

Alex, measuring just off % of THC would not be accurate because different strains are bread for different levels, and growers do not all grow the same strains. The same can be said for lbs ( or grams ) / SqFt, or even profit / sqft. Different climatic geographies, and different licensing requirements all reflect on what needs to be invested in. We have supplied more greenhouses for marijuana growing and more warehouse growing facilities than any other company across North America. As a greenhouse manufacturer I am encouraged to see greenhouses gaining in popularity in this field, though warehouse production also has it’s place, and both have a lot of room for continued improvements in production efficiency, mostly because the growers with plant experience do not have the experience at this scale, and growers with experience at scale need to gain experience with the plant.

Alex white says:

Great reply Leigh. I’m try to get very specific. In the future it won’t be about strains, but rather formulations. Therefore, the cost-per-milligram of raw material is the inevitable future. Specific formulations of up to 12 cannabinoids will provide consistency.

I’m looking past grow methods. I’m looking at production of milligrams and their costs. I believe Greenhouse grows are between $700-$1,200 per pound. The quality, percent of valuable YHC, etc., is my interest. Greenhouse grows seem to be less than 20% valuable MGs. If indoor grows exceed that amount, they may still be more valuable.

Alex white says:

Btw, Leigh.. If you’re not looking a cost per MG, you’re missing the future. It is about dosing and consistency – similar to a pill. It’s not about smoking

Alex I agree that the future is in further processing for oils and edibles, etc. This is not my area of expertise, however, I am not sure there is an easy comparison to the levels of mg produced from flower grown in a greenhouse vs a warehouse. It would seam logical to me that different plant genetics may account for variation in processing similar to other food products, just as the level of THC, CBD, and other varies from one strain to the other cannabinoids.

Alex white says:

Non-smoking consumption is at 70%. It will be 90% in 3 years.

Alex white says:

It’s the raw chemicals. Research I’ve funded indicates the relationship of cannabinoids matters. I speculate that relationship defines the various “highs” or medical benefits. In the end, (3-5 years) it will be about milligrams. That means the grow (or production) will be about chemicals, not strains. Therefore, ultimately as an industry, the cost to produce milligrams of THC,CBD and others will be the most important part of the industry.

I’m focused on that first, understanding both profit and purpose (medical benefits) will be determined by production costs and I intend to win that battle.

It’s not about “growing,” its about production.

bongstar420 says:

Breeders are the only way outs or greens will get anywhere….disease and pests are barely anything now. Wait till all the morons with $ get out there feeding the pests.

Alex white says:

Btw, it’s not greenhouses.

bongstar420 says:

Correct…most growers aren’t good enough to produce consistent top shelf

Concentrates, how ever, are farmer territory…something average people with advisers can do.

bongstar420 says:

Its regional….in Oregon, greenhouses are near parity with indoors..

Our summer greenhouses require cooling and our winter greenhouses require substantial BTU input beyond what a light could supply.

Indoors is better unless you live in a high sun, moderate temperature region with cheap methane.

Wm M Roberts says:

Is there any way to determine what an average yield is per light in a greenhouse grow?

mojave desert heating and air conditing inc. says:

how do you deal with the heat load when its 110 degrees out side with out air cond. ?