3 tips for end-of-year greenhouse maintenance

Greenhouse production serves many purposes, one being to grow healthy crops year-round. While growers may be busier in the warmer months, winter is no time to hibernate and let the technology work alone. Like the plants within them, greenhouses require year-round maintenance. Jeff Balduff, technical sales and services representative at CropKing, explains.

1. Keep heating costs down.

Heating costs are one of the largest expenses in operating a greenhouse in the winter. Growers should make sure their heating equipment is operating efficiently, Balduff says. In the case of older equipment, a certified HVAC professional should check the equipment to make sure no exhaust gases are reentering the greenhouse and that fuel isn’t being wasted. “You want to make sure your air circulation equipment is working correctly, whether it’s HAF fans, or vertical fans, jet fans — anything that’s belt-driven,” he says. “Belts should be inspected and changed as needed if they are getting age to them.” It’s also important to ensure your vents are closing and sealing properly. A vent that was stuck open a few inches in the summer may be forgotten about, but those few inches could cause a headache in colder temperatures.

2. Manipulate crop-specific environmental control strategies.

Crop types can have a large bearing on environmental control considerations, Balduff says. Below are a couple crop specific issues to consider as we transition from the Fall to Winter season.

Tomato: Condensation control is important in the winter months. Modifications to your daytime temperature setpoints and ramp times may need to be made in order to limit the amount of unwanted moisture in your greenhouse. Growers may think that they do not need to run a dehumidifier in the winter months, hoping to cut down on costs, but that is a big misconception. Running your dehumidifier is an important tool in controlling condensation and preventing damage to your plants.

Lettuce: Lettuce and other leafy greens will slow in growth during lower temperature and lower light conditions, however adjustments can and should be made to ensure proper nutrient intake. Plants will be using less water, which means you may need to increase the concentration of fertilizer compared to your routine in the summertime. It’s important that the plants have access to the same levels of nutrients no matter how much water they do or do not use throughout the changing seasons.

3. Change greenhouse covers.

Growers should regularly change their greenhouse covers, especially poly film covers, Balduff says. Reductions in light transmission are generally greater in the southern United States than in the northern part of the country. “That holds true to any kind of poly cover,” he says. “In the case of polycarbonate, it has a lot longer lifespan. You may need to check the light levels in your greenhouse to gage how effective your cover is. Your eyes are a very poor judge of the quality of light transmitting through the cover. As it gets to the end of its lifespan, it may look like its transmitting light well to the naked eye, but in reality there may be issues that you can’t physically see.”  Finding someone with a high quality light meter can take a reading outside and then inside to determine how much light your covers are keeping off the crop.

Photo: Patrick Williams