No matter how well-built a commercial greenhouse is, things can go wrong, especially if you skip regular greenhouse maintenance and overlook early signs that point to needed greenhouse repairs.

Vents get stuck. Dust builds up on sensors. Controls get out of whack.

That’s why we pulled together a panel of greenhouse pros from Prospiant and Wadsworth to talk through some of the most common greenhouse troubleshooting and maintenance challenges—and how to fix them fast.

Here are seven tips from the conversation with Terrell Jones, Project Manager at Prospiant; Nick Earls, Crop Specialist at Wadsworth Control Systems, and Amanda Debevc in Sales at Wadsworth:

1. Crack Open Your O&M Manual

Read your Operations and Maintenance (O&M) manual before things go wrong, not after.

You’ll find it’s packed with useful operational guidance and greenhouse maintenance information. Flip through your manual and you’ll find:

• Technical details and equipment specs
• Instructions for operating and using controls
• Troubleshooting guidance
• Routine maintenance timelines and checklists
• Parts lists and diagrams
• Safety guidelines and procedures

Taking time to review your O&M manual early makes maintaining your greenhouse much simpler down the road, and you’ll prevent many problems before they start.

Tip: Use sticky notes to mark troubleshooting pages you need to refer to often.

2.  Inspect Vents as Part of Greenhouse Maintenance

Make a circuit around your greenhouse, inside and outside, to check your vents for anything that looks off—vents opening unevenly, bent rack arms, motors not working like they should, etc.

Sometimes you’ll find a problem that has a simple fix, like moving plant trays blocking a vent.

During your walk-around, take a close look at the alignment of the rack arm and pinion. Make sure the rack arm is straight and aligned with the pinion. And keep an eye out for motors that stop or only turn in one direction—they may need attention.

This kind of regular greenhouse upkeep helps you catch vent problems early and avoid emergency repairs.

For a deeper look into maintenance for greenhouse ventilation systems, check out the UF/IFAS maintenance guide for greenhouse ventilation, evaporative cooling, and heating systems.

Tip: Carry a good pair of binoculars with you during your walk-around. They’ll save you from climbing up and down ladders to get a good look at your roof vents.

3. Re-time Your Environmental Controller After Repairs

Your vent motors and environmental controller need to work in sync for your vents to open and close properly. If you replace a vent motor but don’t re-time your controller, things can go sideways.

Controllers are set to open or close vents in a specific length of time. For example, 30 seconds to completely open or close. If your new motor runs faster than the motor you replaced, has a different stroke time, or turns in the wrong direction, it can throw off the whole system.

Bad timing can also lead to extra wear on the motor or, worse, damage to your vent system.

So anytime you repair or replace a vent motor, follow up with a controller check to make sure everything’s in sync. Your O&M manual can walk you through it, or your tech team can assist over the phone.

Skipping this step can lead to bigger issues down the road that may require costly greenhouse repair.

4. Flip That Switch Back to Auto

Sometimes greenhouse issues come down to small oversights.

One of the most common? Someone flips a switch to manual and forgets to turn it back to the auto position before heading home or moving on to another task. It’s an easy mistake that can cost you a lot of time and bother. Always double-check those switches before you walk away.

Now and then, flipping a breaker can solve your issue, that is, if you have clearly labeled your breaker panel. Some breakers may be off for a reason. When troubleshooting, it’s difficult to know which ones you can turn on or off without proper labeling.   

Another issue techs encounter frequently is growers programming the heating and roof-vent-opening setpoints too close together—like setting your heating equipment at 70°F and your roof vent opening at 72°F. This causes the systems to fight against themselves. Spread out those setpoints to avoid that internal tug-a-war.

Tip: Even if you’ve used the same setup for years, it’s worth having someone from your supplier do a yearly site visit.

People move, roles change, and systems get upgrades—sometimes without anyone realizing it. A quick retraining visit gets everyone up to speed.

5. Greenhouse Sensors Drive Everything

Dirty and inaccurate sensors give you bad data. Your environmental controller can only make good decisions if it’s getting good information from your sensors.

You may think you need to add extra sensors when really you just need to clean and maintain the ones you already have.

Pay particular attention to your interior sensors because they send critical data to your controller, which tells your equipment what to do to maintain the right greenhouse climate.

Keeping your sensors clean and accurate is a core part of routine greenhouse care that ensures your systems perform the way they should. It also saves you from wasting time on unnecessary greenhouse troubleshooting.

Regularly monitor your sensors and check their placement (they should be at crop level).

Light meters, temperature sensors, and your outside weather station all need regular attention—even if it’s just reviewing the logs.

It’s also a good practice to keep a few spare parts on hand to make quick repairs in case of an emergency.

Tip: Watch for sensors missing their shields and repair them. Move sensors located in areas where direct sun beats down on them or water continuously blasts them to a different location.

6. A Little Attic Stock of Spare Parts Goes a Long Way

Spare fuses. Extra exhaust fan belts. Backup motors. A few glass or acrylic panels or patch kits. These inexpensive parts can turn a crisis into a quick fix—especially during a storm, on a holiday, or when tech support is six hours away.

Designate a spot to store your spare parts and keep them organized and labeled. It’s easier to have an extra part on hand than to experience the frustration of downtime while you wait for a part delivery.

A few parts you may want to stock include:

• Aspirator filters
• Aspirator boards
• A spare probe (to measure hot water)
• Fuses
• Glazing panels (glass, acrylic, etc.)
• Motors
• Limit switches
• Exhaust fan belts
• Pad pump

Smart growers know that preventive greenhouse maintenance starts with being prepared.

Tip: The wait for delivery of greenhouse-specific materials, such as tinted glass or customized opaque panels, can take some time.

Keep a few extra panels of the standard sizes on your greenhouse in stock to spare you two to three weeks of downtime. This simple practice can keep a minor fix from turning into a full-blown greenhouse repair situation.

7. Greenhouse Leaks and Maintenance: What’s Really Going On?

Glazing often gets the blame for leaks—but it’s not always the real culprit.

Before assuming you have a glazing failure, try to diagnose what’s actually going on. Is it a true leak, or could something else be at play, like condensation or a cracked-open vent?

If you notice leaking near the eaves or gutters, check your weep holes. Water backs up into the channels when debris plug the weep holes. A quick clean-out can often resolve the issue.

Here are a few more items to check:

• Gutters and drainage channels: Clogged gutters, especially on gutter-connected houses, can cause water to overflow and work its way inside the greenhouse. Clean them regularly, especially steel gutters, to prevent buildup.
• Vents: Vents can look shut from the ground, but if they’re slightly cracked, water can enter the greenhouse.
• Lapped glass: High wind events, where the wind blows at an angle, can push rain up under lapped glass panels with no sealants. Remember, these systems are weather-proof, not waterproof.
• Condensation: In the early morning, when your energy curtain pulls back, condensation can form when cold air meets warm surfaces. Minimize drips by slowly uncovering the curtains on cold days to ease the transition. This is especially important during the propagation stage.
• Hail damage: Tiny impact spots on polycarbonate and sometimes acrylic panels can become leak points over time, especially after a storm. If you see small dots or streaking on your panels, it’s worth inspecting them for hail damage. Otherwise, the next storm could start pulling your panels out or cause cracking because they’re too brittle.

While it’s normal to have some leaks in your greenhouse on occasion, consistent leak patterns often signal a failure point you need to look at, or they might warrant more investigation from a tech.

Tip: It’s tough to find the source of a leak if you’re focused on just one area. Look 10- to 15-feet upslope from where you find water when greenhouse troubleshooting.

Want the Full Breakdown?

This blog just scratches the surface. If you want to hear more about maintaining your greenhouse, troubleshooting common issues, and repair tips from the experts, check out the full webinar recording here.