Improve Greenhouse Tomato Production with Dehumidification and LED Lighting

Growing tomatoes in a greenhouse allows for better yields and longer growing seasons. Simply growing under cover can be beneficial. However, modern growers are taking things further, increasing yields, improving quality, and reducing costs, all by adopting active dehumidification.

High humidity is a major problem in almost any greenhouse. It’s inevitable, as tomato plants, like most plants, constantly release moisture. High humidity levels cause several issues, affecting yields, and even leading to high energy costs.

Why Does High Humidity Harm Tomato Production?

Tomato Disease Susceptibility

First, is disease and mold development. Tomato crops are susceptible to a wide range of humidity-related diseases, including botrytis (gray mold), leaf mold, powdery mildew, and blossom end rot. These affect fruit set, reducing yields, and harming fruit quality.

Small Yields & Low-Quality Fruit

Second, is by creating sub-optimal growing conditions. Modern tomato production focuses on maximizing yields, by creating an active climate that stimulates growth. Growers achieve this by increasing their control over all factors in the greenhouse, one major factor being humidity.

High Energy Costs

However, controlling humidity requires a lot of energy. Especially when relying on the traditional method of heating and ventilating. Tomatoes are a relatively warm-climate crop. So, the heating needed to compensate for the heat lost through ventilation can be very expensive.

As humidity affects both yield quality, and production costs, tomato growers these days are turning to new solutions. Active dehumidification, such as DryGair, provides an ideal solution to both issues, which many around the world have already adopted successfully.

Using DryGair to Improve Greenhouse Tomato Production and Reduce Costs

DryGair dehumidifiers reduce humidity by actively removing moisture from the air. This allows greenhouse operators to avoid ventilation whenever it’s ineffective or inefficient – overnight or during cold, damp, or rainy days.

As opposed to ventilation, active dehumidification provides a complete solution to humidity, that doesn’t rely on comfortable outdoor conditions. That means growers can create and maintain ideal growing conditions 100% of the time.

One tomato producer that has successfully implemented active dehumidification is Simon Hansen. Hansen is head grower of Miljøgartneriet, the largest tomato producer in Norway, specializing in different tomato varieties.

“Using DryGair, you have a much more even climate, leading to better plant health.” Hansen says. “You can keep your ventilation off, the roof shut, your curtains spread, and create a stable climate, keeping your carbon dioxide inside the greenhouse. This is really good for the plants, and really good for your yield, including the quality of your products.”

DryGair – Active Dehumidification & Air Circulation

All DryGair dehumidifiers include a patented air circulation system as well as dehumidification. The system uses a unique design and powerful fans to release the dry, warm air in all directions at once (360°). This ensures both adequate airflow in the foliage, as well as uniform conditions throughout the space.

By combining active dehumidification with air circulation, DryGair helps significantly reduce disease outbreaks, increases yields, and improves quality. It also saves growers a lot of energy, averaging 50% savings on heating costs.

Like Hansen, many tomato growers around the world use DryGair systems to create an active climate that stimulates growth, flowering and fruit development, while reducing energy costs.

Another example comes from Finland’s largest tomato producer, Svenn Sigg. Matts-Erik Lindqvist, president of horticulture supply company, Hatec Baltic, who works with Svenn Sigg, mentions.

“The company has witnessed substantial energy savings, reaching 50%, as well as 40% savings on CO2 enrichments.”

The Challenge of Growing Greenhouse Tomatoes with LED Lights

LED lights are much more efficient than traditional HPS lamps, such as SON-T, making them a great choice to cut energy costs. However, LED bulbs are also cold, meaning they do not emit heat like other lights. This creates a new challenge for greenhouse growers.

When switching to LEDs, greenhouse operators find themselves in a more humid, yet colder environment. Without compensating for the change, this creates the perfect conditions for mold or disease outbreaks.

In most cases, growers turn to active dehumidification, such as DryGair, to control the excess humidity. Actively removing moisture from the greenhouse allows growers to reap the most benefits from the LEDs.

On growing tomatoes with LED lighting, Simon Hansen says,

“The first year of growing with the LED lights, we didn’t have any dehumidifiers. To be honest, it was a nightmare. We managed to grow, but it was very hard.”

“The climate was very irregular, because of the enormous amount of transpiration from the plants, under the LEDs. That’s where DryGair came into the picture. It was a whole different world – steerable, controllable, beautiful plants, beautiful products.”

Coupling large amounts of radiation with optimal relative humidity levels stimulates the plants, maximizing their activity. Ultimately, this leads to larger yields, higher quality, and shorter grow cycles.

For these reasons, more and more modern greenhouses grow tomatoes under full LED lighting, with active dehumidification.

Adding Thermal Screens and Avoiding Ventilation to Save Energy

When growing with full LED lighting and active dehumidification, ventilation may become inefficient, or irrelevant, in many cases. Ventilation is used as a means to release moisture and reduce humidity. However, it also releases heat, requiring additional heating, which may be expensive.

With active dehumidification, venting becomes unnecessary. Growers can keep the greenhouse closed and retain the heat they’ve already produced. So, to complete the picture, and provide even greater energy savings, many greenhouse operators choose to add thermal screens and other insulation measures to prevent heat from escaping.

“Growing tomatoes with DryGair immediately reduces your costs, simply because you can close your ventilation frames on the roof of the glasshouse. The DryGair units take care of the dehumidification.” says Simon Hansen, of Miljøgartneriet.

“Without dehumidification, as much as 60% of your total heating costs are actually for controlling humidity. So, right away, you have huge cost savings when using DryGair. The actual savings depend on what you grow, where you grow, and how you grow it. But it’s certainly between 30%-60% in Scandinavia.”

Better Tomato Yields, Lower Costs

To sum thing up, Hansen says,

“Overall, it’s clear that you get a healthier and more even crop. If you have a wish for how you want your crop to be, it’s easier to get there with DryGair.”

“You have better control over your environment, you can keep your temperature and humidity more even. This all creates a better balance in your plants. I’ve increased yields by 20-30%.”