Traditionally the best time of year to make upgrades and repairs around the farm is right after the fall harvest, but those who are producing cannabis in a greenhouse have more flexibility when it comes to making upgrades to their facility.
With harvests happening throughout the year, greenhouse growers aren’t confined to making upgrades in the late fall and early winter. Despite this flexibility, it’s still best to make greenhouse upgrades soon after the fall harvest — but for a different reason than traditional outdoor growers.
During the colder months of the year, heating represents one of the largest costs for an operation. With this in mind, it’s surprising how many greenhouse heating systems across the country are in need of an upgrade. Making the necessary improvements to a heating system can lower an operation’s heating costs, allowing for more profitable winter crops for years to come.
When it comes to improving a heating system it’s all about efficiency.
Efficiency ratings should be a major factor — if not the biggest factor — when purchasing greenhouse heaters. The higher the rating, the more heat is created based on the fuel or energy used. Heater manufacturers have put a real emphasis on heating efficiency in recent years, giving many growers the opportunity to upgrade to more efficient heaters. Currently several companies are offering heating units that provide 93% efficiency. The high efficiency rating allows growers to save significantly on their heating costs, while also reducing an operation’s carbon footprint. Luckily, a lot of these heaters are actually small in size and their compact nature makes installation easy and quick, allowing cultivators to spend less time troubleshooting the installation process and more time growing.
When making greenhouse upgrades, it’s natural to worry about the initial investment. While these heaters are certainly not cheap, growers are often making their money back within the first two years, due to the improved efficiency. Plus, integrating energy-efficient heaters will make some operations eligible for utility rebates, so growers in regions offering these rebates should absolutely consider upgrading as soon as possible. Being the first to realize the combination of heating savings and utility rebates can allow growers to set the standard and rise to the top of their local market.
While the actual heating units being used are a major factor, growers can also look elsewhere to improve their efficiency.
Perhaps an even more basic way to improve heating efficiencies is to look at the materials from which a greenhouse is actually constructed. Growers will benefit during winter months from having a greenhouse cladding with a high R-value. A material’s R-value represents its thermal resistance; the higher the number, the better insulation it provides. In cold climates, upgrading to materials with a higher R-value can make a big improvement.
Cold-weather growers should definitely consider using twin-wall polycarbonate. Some operations may prefer the aesthetic value of a glass greenhouse, but for pure functionality, polycarbonate is a far superior option. Three-millimeter glass has an R-value of 0.95. Polycarbonate, which has an R-value of 1.72, reduces heat loss by almost two times compared to glass. This difference alone makes polycarbonate a better and more profitable option, but polycarbonate also has a number of other benefits.
Growers appreciate the durability of polycarbonate. In cold regions it can easily withstand hail and heavy snow loads, and in most cases polycarbonate is accompanied by a 10-year warranty. Polycarbonate is also light and easy to install — a factor that can’t be overlooked since growers will want to make greenhouse upgrades as quick as possible in order to avoid missing valuable growing time. Polycarbonate is light enough for one person to move, and two people working together should easily be able to upgrade the cladding without needing professional installation.
Of course, upgrading to polycarbonate may not be in every operation’s budget, and if this is the case, an air-inflated double-poly film could be a cost-effective way to improve a greenhouse’s insulation. Air can provide exceptional insulation, and forcing air between two layers of poly film creates an effective buffer. An air-inflated poly cladding can provide an R-value as high as 1.5 and is cheap to purchase and quick to install.
When using this cladding, growers are able to feel the actual warmth being preserved just by touching the greenhouse wall. The interior wall generally doesn’t accumulate condensation, as this tends to happen between the two layers. Condensation will run to the bottom of the film and can be easily drained to avoid any mold or bacteria issues.
It’s also important to note that the fan used to provide the inflation consumes little power — often comparable to a light bulb — so growers really don’t have to worry about additional energy requirements.
Make the Upgrades
Cannabis growers using greenhouses have a lot of advantages when it comes to flexibility regarding timing of repairs and upgrades.
A lot of cold-weather operations can improve their business substantially in the winter by upgrading their heaters and by taking a look at the R-value that their greenhouse cladding provides. Making conscientious upgrades to a heating system can allow for a quick return on investment and make winter crops more profitable now and well into the future.
Christopher Machnich is a digital marketing manager for GrowSpan Greenhouse Structures (www.GrowSpan.com). He is a cannabis industry enthusiast who loves reading and providing content for many industry publications. His points of interest are greenhouse and hydroponic production, as well as the cultural and economic impact of cannabis legislation.