Tips to avoid common, costly greenhouse mistakes

All Photos by Kayla Matherne

Cannabis is a living, breathing plant, so it is imperative that you provide it with the variable light, irrigation, inputs, temperature and humidity that it requires. Being adaptable in and around the greenhouse — and on the go — will take you far in maintaining an optimal greenhouse environment.

Follow these nine tips to prevent expensive pitfalls and keep things running smoothly.

1. Winterize your system and facility.

Properly going through your systems before the winter and ensuring everything will work at full efficiency, when necessary, can be the difference between being profitable or not during the most challenging grow season.

If you are not running your greenhouse in the coldest months of the year, make sure to drain all water pipes, reservoirs and evaporative pads to save you from having to replace frozen pipes and possibly pay an expensive repair bill. Turn off all power when possible and unplug everything you can to prevent machinery from drawing power while not in use and to avoid fires.

If the greenhouse is in use, be sure to test run your boiler and/or heaters before they are needed. If necessary, get a technician out to fire them up for the first time. This is necessary if you let your system completely run out of gas or if it has been a while since you have used them. Still, make sure to empty any evaporative cooling systems and insulate any piping that could be exposed to the cold. Wrapping exposed pipe with insulating foam and sealing cracks in the structure around them should be a quick and simple fix if kept up with yearly. Check your floor heating system (if you have one) for leaks once everything is at operating pressure.

The final step in the winterizing process is to seal your greenhouse as much as possible. Seal around exhaust fans and cover them if you will not use them in the winter months. Check to make sure any automated windows seal completely when closed and adjust if necessary.

2. Check your cooling systems.

Spring is the best time to work on these different cooling elements of your greenhouse before it gets too hot and the equipment is in great demand.

Checking for leaks in your pad pump and waterwall system is a quick way to save both water and money. Small leaks can add up and get worse over the summer. Sealing up any PVC leaks and making repairs to those pipes will help you be more efficient during peak season.

Make sure your fan belts are tight and in decent shape to help them run at optimum efficiency. Check to see if they are tattered or frayed. Pull on them to ensure they are tight but also to make sure they are not brittle. Double check that all your horizontal air flow (HAF) fans are working properly and replace them if necessary.

Finally, make sure all mechanical parts work correctly, like side wall vents, shade curtains and roof vents that open and close.

3. Maximize square footage.

When trying to maximize your grams per square foot, you want to expand your canopy or square footage as much as possible. One way to avoid later regret is to always have more than one person look at the layout before making any permanent or semi-permanent decisions.

Use equipment as it was intended to be used. For example, if you are using rolling tables, make sure you place them in a way that maximizes the rollers and does not limit them.

Try to limit walkways. If you can make them smaller or share one between growing canopies, you will be able to quickly free up space in the greenhouse.

Lastly, choose the smallest size pot possible that you can flower in without getting root bound. In addition to saving money on soil, this will allow you to fit more plants in an area in less expensive pots. Every time you transplant and touch the plant, you are adding expensive labor hours.

4. Acclimate your plants.

Cannabis, like any plant, has an ideal environment in which it grows best. This can even be cultivar-specific, but given a few months’ time, most new cultivars will eventually adapt to your greenhouse. With seeds and clones alike, try to look for plants that seem to be more resilient to pests and mold. If they seem to be able to keep pests away or fight mold off, then think about taking cuttings or making those plants into mothers. These more resilient plants and cuttings will speed up the acclimation process while simultaneously also helping with IPM and plant health.

5. Always double check your systems while you’re away.

Automated systems are crucial in a greenhouse, even just when it comes to heating, cooling and lighting. Being able to step away from the facility and not require someone to watch it 24 hours a day is not only practical — it’s usually cost effective.

The downside is those systems must be trusted while you are away from the facility. Check camera systems to make sure your lights are running through the night in the vegetative zones, light bleeds are not happening at night in your flowering zones, and any other automated system (like blackout cloth) is working properly. At least once a quarter, or any time you switch a setting, check cameras to make sure lights are working and no light leaks are happening — this can be the difference between a great harvest and one full of seeds or all your plants in veg going into the flowering cycle.

6. Train for vacation.

It’s important to properly train your team for when managers are away so multiple people are able to take the reins when people are out on vacation or sick. This includes designating someone to operate all backup systems, make fertilizer decisions, operate any environmental controls, troubleshoot small problems, handle emergencies and any other duty the manager would normally take care of, including either contacting ownership or making a major decision in a split second if necessary.

Run through those processes with the trusted employee or employees regularly, whether it is logging in or giving them a once-over on the system. Make sure they are completely confident in an emergency. There are always going to be times when you are unreachable, and making sure they can act in a timely manner to avoid further crisis is imperative.

7. Stay compliant.

This tip is, by far, the most important and may also be the most costly if not thoughtfully planned for. Normally new rules or regulations come out at least a few months before they are enforced, and they sometimes can add a grace period as well. It’s critical to look through the rules as a company or have a third party that is responsible for compliance update you on the new rules as soon as possible. Then you can make sure you have everything you need well in advance of the deadline.

Before any new regulation comes out that could affect an item, such as packaging, make sure you test that item and figure out how you are going to incorporate the new regulation in your standard operating procedures (SOPs) to follow the new rules.

Finally, conduct weekly in-house compliance checks. Have one person check the compliance of a few areas of your operations once a week, trying not to check the same thing consecutive weeks, unless it is at risk of becoming non-compliant. Dedicating a couple hours to this each week will allow them to catch little things that may have slipped through the cracks and save you from potential fines.

8. Do not fall behind on maintenance.

Maintaining your greenhouse not only increases the lifespan of your investment but also can increase profits by keeping the greenhouse running optimally and plants growing quickly.

Whether you hire a full-time, part-time, or third-party maintenance company, make sure the greenhouse is structurally sound. Grease motors and moving parts like racks and pinions, and make sure they are working properly at least twice a year to ensure your systems are operating smoothly, which could save you from catastrophic failure.

Also, designate someone available in case of emergency repairs if they cannot be done in-house. Be sure to have your HVAC systems maintained regularly.

Last, but certainly not least, do not forget about your septic system if you have one, and have it emptied regularly.

9. Do not forget to adjust your systems.

In most U.S. climates, the winters and summers are vastly different, and with those changing temperatures and light exposure levels, you may need to adjust many of your environmental controls.

It is important to remember to adjust your lights for daylight saving time in the spring, and it is also a good time of year to adjust temperature settings, make sure you turn on your waterwall, reevaluate any light plans and make any light-level shutoff adjustments, if necessary.

The same thing goes for the fall season — make sure your heating settings are set optimally, boiler units are available in the system, heaters are turned on and the lights are adjusted to account for the darker winter days.

Always remember to turn off your lights when there are no plants under them; if there are no plants under the lights, they do not need to be on, wasting power. However, leaving environmental controls on may be necessary to prevent freezing or overheating.