How Do Container Farms Allow for Year-Round Growing?
Could the conventional growing season eventually be a thing of the past? Historically, farmers have been entirely dependent on the cycle of the seasons, not to mention favorable weather, to grow their crops. Today, however, controlled environment agriculture (CEA) facilities and techniques allow produce to be grown all year round, at any time and in any climate.
How exactly do these cutting-edge facilities manage to replicate, every single day, the perfect spring or summer day that most crops need to thrive? The answer is advanced climate control equipment and methods.
Container farms, for example, like the shipping container models from companies such as Freight Farms, are fully kitted out with advanced features that allow for perfect growing conditions inside, regardless of what the weather might be like outside. As described in a recent Freight Farms blog post, these features include:
Heavy-duty insulation
An uninsulated shipping container isn’t a very effective growing environment on its own — metal simply allows heat and cold to pass right through from the outside to the inside. To help maintain a consistent, ideal temperature inside the shipping container, it must be effectively insulated. The growing units from Freight Farms, for example, are lined with a custom-built layer of R-28 insulation (R-values relate to the system that is used to measure how effective insulation is; the higher the R-value, the better the insulation).
For comparison, a typical refrigerated container has an insulation rating of just R-16. A level of R-28 helps keep the environment inside the container cool in the summer and warm in the winter, just the way plants like it.
Environmental sensors
The electronic systems that run inside a container farm are impressively high-tech. At the center of this setup is a series of environmental sensors that are constantly measuring and monitoring specific climate conditions, such as humidity levels and temperature, inside the container. The sensors then relay this information in real time to the in-farm controller, which makes automatic adjustments as needed to other equipment inside the container to keep the environmental conditions consistent.
LED lights
If you’re wondering how crops get the sunlight they need to grow inside a shipping container, the answer is they don’t have to! This is because container farms like the Freight Farms module are outfitted with high-efficiency LED lighting systems.
These systems are typically optimized to deliver only the red and blue spectra of light that plants need to grow. Interestingly, plants don’t use or require all the wavelengths that are available in sunlight, which is why most container farms or vertical farms you see are illuminated by a purple glow.
Furthermore, in the Freight Farms growing system, these LED lights not only provide light, but they are also the key heat source for the container. Believe it or not, the LEDs generate enough heat that there is no need for a traditional heater inside the container, even in very cold climates.
Air conditioning
It’s just as important to protect growing crops from extreme heat as it is extreme cold. To achieve this, container farms keep things cool with in-container air conditioning systems.
The Freight Farms unit, for example, uses a 36,000 BTU A/C system, which offers the same output as a commercial freezer and includes an integrated economizer that gauges outdoor temperatures through a special sensor. This device lets the system pull in colder air from outside on days where outdoor temperatures are lower than those inside the container. This allows the farm to be cooled passively rather than by running the air conditioner, saving energy.
Dehumidifier
Plants certainly need moisture to grow, but when humidity is not properly managed inside a container farm, it can have a serious, negative impact on plant growth and farm yields. Excess humidity is most likely to be a problem when temperatures inside and outside the container are very different. To address this issue, container farms use dehumidifier systems (sometimes, although not necessarily, integrated into air conditioning units) to pull the extra moisture out of the air inside the container. Some systems allow this moisture to be filtered directly back into the farm’s water supply tank, which nourishes the plants, thus reducing water usage and helping create a circular water system.
Tips and tricks for farmers
In addition to all the features described above, there are some simple tips and tricks that container farmers can use to help make sure that growing conditions inside the unit are as ideal — and as easy to maintain — as possible. For example, farmers can:
Choose a shady site — Whenever possible, farmers should ensure that their container units are placed in a shady site to limit direct sun exposure. This helps things stay cool and reduces the electricity costs of running an air conditioner during the hottest months.
Choose a light color — It’s common for the exterior of a container farm to be covered with a vinyl wrap for both protection and branding. Choosing a light-reflecting wrap color, such as white, prevents the container from absorbing too much sun.
Make use of snow — Container farmers who live and grow in colder climates have access to a surprising source of insulation: snow! Piling snow up against the sides of a container farm is like adding an extra layer of insulation, and helps keep the in-container environment toasty warm.
