As much as cultivators wish they could predict what their outdoor growing season will be like, they are always at the mercy of Mother Nature. Whether it’s an early freeze, smoke pollution, drought or hailstorm, extreme and volatile weather patterns are becoming more frequent and are an increasing threat to our crop yield and food supply.
Greenhouses can and have been a solution to this issue as they allow farmers to grow in a more controlled environment that is more protected from outside conditions. Some greenhouse designs are better than others when it comes to all-season or all-weather durability. In this blog we will discuss what makes a greenhouse an all-weather greenhouse and give recommended greenhouse system setups for different climates.
What makes a greenhouse an “all weather” greenhouse?
Simply put, an all weather greenhouse is designed for durability with high quality materials. In order to endure strong winds and/or heavy snow falls, depending on your location, a greenhouse should have a strong frame made out of metal, such as aluminum or steel. At Ceres, all of our greenhouse frames are built with galvanized steel and we design truss spacing to accommodate local snow and wind loads. Other greenhouse materials like polycarbonate (for the roof glazing) and insulated metal panels (for the walls) increase structural durability and help make a greenhouse an all-weather greenhouse.
An all-weather greenhouse, or an all-season greenhouse, should be insulated so as to better retain heat and prevent large temperature fluctuations within the growing space. Greenhouses use free energy from the sun for plant growth and heating. With insulated walls, heat is less likely to escape, which decreases the need for additional energy input. This is especially helpful in places with cold climates. Stability of the indoor environment is also necessary to ensure plant health and robust growth.
Ceres greenhouses optimized for all seasons are built with passive solar design principles. A passive solar greenhouse captures sunlight that would otherwise be wasted and reflects it back onto the plants. This is achieved by orienting the greenhouse to the south, with the long axis of the greenhouses running east/west and. The north wall and roof of the greenhouse is insulated to help “harvest” sunlight and keep it in the greenhouse. This type of design ensures higher light levels in the winter, which is beneficial for growing year-round or for growing in northern regions.
For more information on the benefits of passive solar design, check out our blog Light Harvesting Advantages of Passive Solar Design.
Even with all the attributes mentioned above, an all weather greenhouse will rely on integrated climate control systems to maintain a healthy growing environment. Traditionally, greenhouses in less temperate zones require a lot of heating or cooling and use a lot of energy to operate. That’s why it’s beneficial to implement appropriate technologies where possible to regulate greenhouse temperature and humidity levels.
At Ceres we have two different types of geothermal systems to help with heating and cooling, the GAHT® (ground to air heat transfer) system and the EcoLoop™.
To learn more about them and compare their capabilities, check out our blog Ceres GAHT® System Versus The Ceres EcoLoop™, Which Geothermal System Is Right For Your Greenhouse Operation.
Greenhouse Environmental Control Setups For Different Climates
Now that we’ve covered the main attributes of an all-weather greenhouse, let’s talk about the integrated systems within. The following graphs offer a range of recommended equipment setups for different climates in the US. We created these graphs to align with Ceres’ vented greenhouse design but they give a good idea of the systems needed to maintain comfortable growing conditions year-round.
Climate Zone 1 – Marine
*PCM stands for “phase change material” and is a greenhouse wall covering that consists of pockets of a substance that is constantly changing from a liquid to a solid. When the material changes phases it releases or absorbs heat, passively heating or cooling the growing space.
As you can see, this graph represents improvements of the yields in terms of quality and consistency in respect to the investment of additional equipment. It is possible to grow year round with minimal equipment. However, additional equipment will achieve a more optimal environment and more consistent yields.
For zone 1, the key climate considerations for greenhouse equipment are high relative humidity in the winter and low relative humidity in the summer. In this region there are moderate temperatures year round.
Climate Zone 2 – Cold & Very Cold
According to this graph, the key climate considerations for greenhouse equipment in this zone are very low relative humidity in winter and high relative humidity in the summer. The winters here are very cold and the summers are warm to hot.
Climate Zone 3 – Hot Dry & Mixed Dry
Key climate considerations for this zone are low relative humidity year round, very hot summers and moderate winters. In this zone there can be wide temperature swings in a 24-hour period with cool evenings even during the hottest months.
Climate Zone 4 – Cold & Mixed Dry
In this zone there is relatively low humidity year round with moderate temperatures in the summer and cold temperatures in the winter.
Climate Zone 5 – Mixed Humid
The key considerations for greenhouse equipment are the hot summers and cold winters in this climate. Relative humidity is moderate to high year round in this zone.
Climate Zone 6 – Hot & Humid
Not only does this zone get a lot of sun, the relative humidity here is very high year-round. Other climate considerations are the very hot summers and the warm winters.
Whole System Greenhouse Design for Any Climate
To recap, an all-weather greenhouse should have the following:
- High-quality and durable building materials
- Insulated walls and roofing material
- Passive solar design principles
- Energy-efficient climate control systems
- A custom equipment setup to align with climate considerations and growing goals
In order for a greenhouse to perform its best in any climate, year-round, it must be designed as a whole system from the get-go. At Ceres we specialize in just that. We work closely with our clients to deliver a system suited to their needs and goals and that will support healthy plant growth in their local climate. When we combine our greenhouse design with handpicked customized systems, we provide our growers with a holistic grow-solution that will increase their productivity while helping them save on energy costs.
We’d also like to note that all-weather greenhouses do more than just offer heightened crop protection and increased yields. They allow us to build local food systems in places where perhaps it previously wasn’t possible. When we diversify where we grow our crops we increase our overall food security and decrease our food miles – beneficial for us and the environment.
We’re here to help you with your all-weather greenhouse project. If you have any questions or are ready to get started, contact a Ceres greenhouse expert today!
