Advice Articles

Humidity Control – Keeping Crops Fresh From Farm To Table

June 10, 2022

The EU has over 2.2 million hectares dedicated to growing vegetables and leafy produce, and 3.2 million hectares to growing fruits. This produce is then picked, packed and shipped to countries all over the world. But have you ever wondered how farmers and logistics companies manage to keep crops fresh and edible? The answer is simple – humidification. Humidification is important for two main areas of crop production: post-harvest crop care, and extending the shelf life of crops.

Post-Harvest Crop Care

Once crops have been harvested and other products created and packaged, they need to be transported to stores with enough life left in them to survive on the shelves. Humidification (also known as fogging) promoted faster, more efficient cooling, using less energy in the process. In post-harvest, ultrasonic humidity control solutions are the tool of choice. This is because they use a finer water droplet size rather than high or low-pressure systems.

Keeping crops hydrated post-harvest is incredibly important, as it has a huge impact on their quality, flavour and lifespan. Once you separate the plants from their roots they will quickly dry out, especially in refrigerated environments. You can’t avoid refrigeration elements of harvesting, so instead farmers focus on how to reduce the amount of moisture the crops lose.

Reducing the temperature of produce without dehydrating it is a common problem. This is especially the case when the main market uses refrigerated air-cooling systems to get the job done. If not handled properly, refrigeration could damage delicate crops like herbs or other baby-leaf varieties. This is through harsh cooling methods such as blast chilling, leaving you with weak, dehydrated and broken produce. If you don’t believe us, one of the ways to tell how much your crops are being dehydrated is to measure the defrost water from the refrigeration system. It’s often alarming just how much water is being removed from products, simply through blast chilling.

The solution they came up with was called ‘fogging’. By ‘fogging’ the environment with a steam humidifier, transporters can sustain the life of these foods through natural hydration. This process uses ultra-pure water in fog particles to reach into every corner and stop dehydration from occurring.

Extending Shelf Life of Crops

Crops need to be stored ready for transportation and arrive in shops with enough life for the homes of buyers. With delicate crops like lettuce, this can present a real challenge.

Humidity control systems are needed at all stages of the produce’s life, starting in the picking trailer. By misting the field trailer, farmers can start the cooling process while the produce is still in the field, as soon as it had been picked. These misting devices produce a thin layer of moisture which can then evaporate during transit, stopping moisture being drawn from the produce itself.

Once the crops have been delivered into cold storage, most major growers, packers and shippers will then use an adiabatic crop hydration system to extend shelf life before shipping. These systems are now a standard part of all new-build cold storage units, but they can be retrofitted into old ones too. The idea is to humidify the air in the cold room to about 95% RH (Relative Humidity), and then fill the room with superfine purified water – to the point that it creates a visible fog. This allows moisture to fill every corner of the room using a vapour pressure system. Because the vapour pressure in the room is higher than the vapour pressure of the plants, it encourages the plants to draw in moisture through their stoma. This means that baby leaf crops, salad and brassicas can stay hydrated and field-fresh for up to 11 days.

At Humidity Solutions, we supply humidity control solutions to farms, cold stores, packaging plants and more – helping provide the perfect environment for crop harvesting every time and maximizing profit by preventing spoilage. If you would like to know more, get in touch with us today on 01372 571200 or email info@humiditysolutions.co.uk