Winterizing Greenhouses 

As the photoperiod begins to shift and plants begin to sex, farmers across the Northern Hemisphere are preparing to reap the bounty of their work.

As the flowers begin to form and harvesting and processing areas are cleaned up, built out, and prepared to receive the crops we must also turn our attention to shorter days, cooler nights, and temperatures that will drop before we know it. In preparation for the turning of the seasons, how can you prepare to winterize your greenhouse?

The answer is, it depends.

It depends on what kind of structure you have, how late your last cycle will finish, and whether or not you plan on running plants through the winter.
At FFg, with over 30 years of Cannabis cultivation experience and over 14 years of designing commercial light dep greenhouses, we have some suggestions that may apply to your specific scenario.

Non-Code Structures
Firstly, any non-code, unengineered structure will most likely not hold up to the load requirements of snow, ice, or winter winds so it may be best to take your cover off and let it ride through the cold months.
The benefit of this is that your ‘ribs’ won’t get bent, covers will remain untorn and worthy of another season and any bug pressures will most likely be cleaned out from the cold weather.
Make sure when storing your greenhouse and blackout tarps that they are clean, dry, and placed in areas free from potential rodent damage.
Engineered structures and buildings designed to accommodate the varying load requirements have the ability to be upgraded and prepared to grow late into the season or through the Winter so that you are Forever Flowering.

As the Sun goes lower into the horizon so does the quality and efficacy of the light growing your plants.
As we grow late into Fall and into Winter, supplemental lighting is required to continue to produce top-shelf flowers with the type of structure that the commercial market is expecting so as to not have to process the flower as biomass bound for extraction.
Lighting allows you to extend the amount of light the plants are getting in the latter parts of the season when the amount of hours of Sunlight begins to dramatically decrease.
In addition, supplemental lighting will allow you to increase the spectrum and lumens and/or micromoles that your plants are exposed to.
When considering what type of lighting to invest in please pay attention to your local and State regulations as some States are talking about implementing regulations for certain types of lights due to their electrical draw as early as 2023 and these regulations should be taken into consideration with your business plans.

Heat is more important than most people tend to prepare for.
When the temperatures drop so does the ability of your plant to photosynthesis and grow to its maximum capacities.
The root zone is the most important part of the plant to be kept warm.
In fact, when the soil temperature drops below 55 degrees growth more or less ceases to occur.
Soil temperature is most ideal in the low 70s and everything between 55-low
70s will begin to decrease production.
Because root zone warmth is the most critical we focus on the most efficient approach, radiant root heat.
At FFg we design engineered systems that go just under your plant’s roots including heating systems for rolling benches, plants on the ground as well as ‘in-bed’ heat for plants growing directly in beds.
These closed looped systems are offered with 97% efficient boilers and come in LP and NG fuel options.
As the radiant heat warms the root zone the heat also passively rises through the canopy of your plant providing the majority of the plant’s heating needs.
Though forced-air above canopy heaters are less expensive to initially acquire and install they don’t provide the amount of root zone heat fully desired in a year-round grow space.
We recommend these styles of heaters to reduce condensation and make for a more comfortable work environment though they are greatly less effective than the radiant systems.
In addition, every time your greenhouse is ‘cycled’ for fresh air all of the environmental warm air from forced heat is removed along with the ‘old’ air and the cycle of heating starts over whereas a radiant system will provide a heat blanket to the root zone that remains even as fresh air replaces the old, moist, stagnant air.
Also, consider that though a greenhouse cover should not be depended on for an R-value, a light dep curtain can be closed throughout the night reducing the volume of air in the greenhouse needed to be treated as well as creating an R-value to hold in heat and keep out the cold!

Molds and mildews can devastate your crop in its’ last weeks and days as the buds get greasy and dense with crystals and often from a reduction in airflow due to the increasing plants mass in the greenhouse, evaporation from overwatering, condensation and wet/foggy weather outside.
Though some debate the acceptable levels humidity/relative humidity or Vapor Pressure Deficit (VPD) science has shown that it is the ‘dew point’ that is needed to be avoided in order to reduce or prevent these types of dis-eases from setting in and destroying your harvest.
The two most effective ways of accomplishing this is with ample air movement, a ‘happy plant is a dancing plant’ and with a quality dehumidifier.
FFg offers engineered solutions for the dehumidification of your grow space so that it is done in the most effective, efficient and cost favorable manner to stay within the desired parameters of your operating budgets while continuing to create the ideal environment to grow healthy and abundant plants.
For many locales, dehumidification will ‘make or break’ your harvest in the late Fall, Winter and early Spring so plan on investing in the proper equipment if you plan on growing year-round.
Growing in an automated greenhouse properly designed for year-round cultivation is possible in just about any location on the planet with the correct amount of supplemental heat, dehumidification, and lighting, in concert with an environmental controller to take the guesswork out of what is needed when.

Though warranties on the construction of high-quality greenhouse covers may last for many years, the reduction in the amount and quality of light penetrating those ‘skins’ may occur more rapidly depending on the location and intensity of the seasonal factors on those covers.
Indoor growers understand that even though their grow light shines bright there is a reduction in its efficacy cycle after cycle and the same can hold true when we consider the cover, or ‘filter’, of the Sun entering your greenhouse.
The Winter months could be a great time to reskin your greenhouse in preparation for the next season.
A high-quality, woven greenhouse cover with the correct amounts of light transmission and diffusion is the single most cost-effective way to improve the quality and quantity of the flowers you produce!!!

top tier greenhouse fabric

Winter is also a great time to retrofit your structure with a new automated light dep system.
We are excited about our new internal Omniverse(™) light dep system that has been designed to retrofit any structure with 90-degree angles (no hoop houses).

Whatever your Winterizing needs are, our highly qualified staff is here to answer your questions and obtain whatever products are needed for your project’s needs to continue to grow into the future of your company’s business plans.
Contact FFg today to have a specialist begin your greenhouse retrofits and upgrades including light dep, mechanical intake, and exhaust, air circulation, lighting, dehumidification, heating, reskinning, rolling benches, or steel building designs.
Here is to a healthy, safe, and abundant harvest!!!