Tips for Using a Greenhouse Monitoring System to Protect Your Cannabis Plants


Water pH Sensor

Many commercial cannabis growers raise their crops in greenhouses to protect their plants from outdoor elements, to control environmental conditions, and to harvest throughout the year. However, even with regulating the conditions inside your cannabis greenhouse, you need extra protection to make sure they aren’t fluctuating outside of your set ranges, which could indicate a possible problem that can harm your plants.


Properly selecting and installing a remote monitoring system can help cannabis growers identify trends in environmental conditions to make sure they aren’t fluctuating outside of pre-set ranges, which could indicate a possible equipment problem that can harm the plants and future profit.

Conditions to Monitor

Temperature: Cannabis plants are happiest when the air temperature is between 70°F and 80° F. You’ll need to adjust the temperature depending on the plants’ growth stage and desired densities. That’s why you should place temperature sensors throughout the facility. They should be next to your thermostats and in the center of your greenhouses, preferably away from direct sunlight.
• Humidity levels: Low relative humidity (RH) can cause water to evaporate too quickly for photosynthesis, while high RH can cause mold and fungus. Because the ideal RH range varies for each growth stage, it’s important to monitor and track which level works best for your plants at the different phases. Cuttings and seedlings grow best with a higher RH. But as the plants develop, you should decrease the RH.
Power supply: Obviously you want to be notified immediately of any power outages. Critical greenhouse equipment that requires consistent electrical flow includes your lighting systems, water wells, heater fans, ventilation fans, louvers, sprinkler/watering systems, humidifiers, and dehumidifiers.
CO2 levels: The amount of carbon dioxide required for your cannabis depends on the size of the facility and the amount of light the plants are receiving. A standard cannabis grow area can maintain a CO2 range from 1,000 to 1,500 parts per million (PPM). A level below that threshold can result in slower growth of the plants, while a level above results in unused and wasted CO2.
• Irrigation and soil moisture: Monitoring your soil moisture level is vital to the long-term health of your cannabis. When the soil is waterlogged, the roots will become oxygen deficient and die. The size of your greenhouse, temperature, and humidity affect the soil’s moisture content.
Air circulation: An exhaust system helps control the temperature and humidity, while preventing the invasion of mold and pests that thrive in hot, stagnant air. Automatic ventilation systems include vented roofs, side vents, and forced fans that run on electricity. Therefore, it’s important to place sensors on these units to alert you if they stop running or begin operating outside of preset parameters.
Water pH: Monitoring the pH level will help you to prevent nutrient deficiencies caused by over- or under-acidic water. Look for a monitoring system that accommodates a pH sensor with an adapter that allows it to screw into a water supply pipe. Once installed, the sensing element samples water as it runs through the pipe.
Greenhouse security: Whether your greenhouse operation is in a secluded or populated area, any intruder could be detrimental to your overall yields and profit. Remote monitoring systems can give you peace of mind and instantly alert you when there is an unwanted presence in your greenhouse.


A sample greenhouse monitoring data log

Selecting the Right Monitoring System

Base units: Each condition in your greenhouse that you want to monitor requires its own input on the base unit of the monitoring system. A good fit for a smaller cannabis greenhouse may be a lower-cost, non-expandable monitoring system. An expandable system would work for larger facilities with many monitoring points and those poised for growth.
The monitoring system should have an internal rechargeable battery backup to ensure continuous monitoring and alerts in the event of a power outage. To protect it from moisture, dirt and other hazards, make sure the base unit comes in a weatherproof enclosure.
Hardwired vs. wireless sensors: A hardwired monitoring system connects the sensors to the base device with wires. Generally, trenching long distances for wires is time consuming and costly. A wireless system uses built-in radio transmitters to communicate with the base unit. Some monitoring systems can accommodate a combination of hardwired and wireless sensors.
Communications to your site: Monitoring devices that use cellular communications must be registered on a wireless network (like Verizon or AT&T) before you can send or receive messages. Therefore, it is important that there is sufficient signal strength at the greenhouse. It is a good idea to check the signal quality in the area before purchasing a cellular product. If the cellular network has less than desirable coverage, it’s possible to install an external antenna to help increase the cellular signal.
Alarm notifications: When a monitoring system identifies a change in status, it immediately sends alerts to people on the contact list. If you don’t want all of your personnel to receive notifications at the same time, some devices can be programmed to send alerts in a tiered fashion or on a schedule. Multiple communications methods like phone, email, and text provide extra assurance that you’ll get the alert. Check the number of people the system can reach and if the system automatically cycles through the contact list until someone responds. Make sure the system allows for flexible scheduling so that it doesn’t send alarms to off-duty personnel.
Programming and status check: Select a system that delivers real-time status of all monitored conditions and sensor readings on demand. Options to access your sensor readings include calling to check status, viewing a web page or accessing it via an app on your mobile device. If you don’t select a cloud-based system, you will be limited to logging in through a local area network. Both allow you to make programming changes, access status conditions and review data logs. If internet connectivity is not available at your location, you will want to choose a cellular or phone system rather than an Ethernet-based option.
Data logging: Monitoring systems provide data history that is valuable in identifying trends in greenhouse environmental conditions. Identifying unusual patterns could provide insight regarding potential equipment complications. Monitoring systems record tens of thousands of data points, dates, and times. Cloud-based logging provides an unlimited number of records for users to view, graph, print, and export data trends.
Return On investment: When deciding how much you should pay for a remote monitoring system, tally up the entire cost, fully installed with additional peripherals and sensors and any labor fees for installation. Then consider the value of your cannabis plant inventory and greenhouse equipment. Finally, factor in the cost of downtime, should an environmental event shut down your operation for a period of time.