5 ways to improve temperature and humidity in the greenhouse

Successful growers know how to adjust their greenhouse environment inside to complement changing environmental factors outside. Here are five ways to do just that.

1. Look at humidity levels.

Many growers who have problems with their plants wilting are focusing too much on temperature levels in their greenhouse and not enough on humidity, says Steve Froehlich, horticultural engineer and crop consultant at CropKing. Growers who are still heating at night should be aware of the high amount by which relative humidity drops once the sun comes up and forces the fans on. “Sometimes it’s better to let the temperature rise a little bit more in the greenhouse and slow down that ventilation rate, he says. It’s preferable over maintaining a constant temperature by bringing in dry outside air, but at the expense of the humidity levels, which will plummet.

2. Adjust electrical conductivity (EC) levels depending on humidity.

When the relative humidity in a greenhouse drops, growers can decrease the EC of the nutrient solution so the crops can take up water faster, says Jim Brown, horticulturist at CropKing. When relative humidity jumps, increasing EC can reduce or prevent damage to the crops.

3. Adjust watering levels to accommodate humidity.

When relative humidity drops, growers can increase watering, and when relative humidity jumps, they can reduce it, Brown says. “These problems occur because of quick and drastic changes,” he says. “Environmental control systems are not designed to anticipate these changes nor are they designed to react so drastically and quickly as is needed. That would cause more problems when quick actions are not needed. Growers need to override their automatic equipment in order to minimize or eliminate plant damage.”

4. Wet floors when relative humidity drops.

When the relative humidity drops, growers can wet down the floors to bring the humidity back up, Brown says. Froehlich agrees, claiming that by spraying or wetting the floor, growers can get more moisture into their greenhouse.

5. Turn on your evaporative cooling pad.

In general, the water going over an evaporative cooling pad is in the last stage of cooling, Froehlich says. “This time of year, if you’re battling humidity problems, have that water come onto the pad in maybe your first or second stage of cooling, so that you’re getting some moisture into that air you’re bringing into the greenhouse as you try to control temperature,” he says.

Photo courtesy of CropKing