A common mistake in greenhouse automation is choosing the wrong greenhouse controller for your operation.
It’s easy to invest in greenhouse climate control systems that have features you’ll never use, or buy something that’s too basic.
Consider how much of your greenhouse you want to manage hands-on versus letting automation do the job for you.
This gives you an idea of the capabilities your environmental controller needs to manage your automated systems.
When you match the level of control you need with the right type of greenhouse controller, you get great results without spending more than you need to.
How Greenhouse Controllers Work and What Each Can Do
A greenhouse controller can range from a basic thermostat to an advanced computer system that practically runs the greenhouse for you.
Greenhouse climate controls fall into three categories:
- Thermostats/Stand-alone controllers: Control a single system. Do not communicate with each other.
- Staged/Step-Based Controls: Turn on/off groups of equipment in steps or stages based on set trigger temperatures.
- Integrated greenhouse control systems: Also known as climate computers. They manage multiple systems and/or multiple zones using unified logic.
The table below illustrates the main differences between the three categories. Special thanks to Patricia Dean of Wadsworth Control Systems for providing key information for this table.
| Control Type | Control Level | Systems Integration | Sensor(s) | Remote Access | Logging/ Graphing | Applications |
|---|---|---|---|---|---|---|
| Thermostats/ Stand-alone controllers | Single device | No | One internal sensor; variable accuracy, difficult to calibrate | Sometimes | Minimal or none | Hobby houses, simple greenhouses, low-budget applications |
| Staged/ Step-Based Controls | Multi-stage for one zone | Limited (equipment grouped by stage) | One zone sensor + optional weather sensors | Often yes (many have apps/cloud) | Basic logs and simple graphs | High schools, home greenhouses, garden centers, low-tech commercial houses |
| Integrated greenhouse control systems | Multi-system, multi-zone, unified logic | Yes (heating, cooling, vents, shade, irrigation, CO2, lighting, etc.) | Multiple sensors per zone; averaging + weighting | Yes—common standard | Advanced data logging, trending, analytics | Universities, research, botanic gardens, CEA, large-scale commercial |
Thermostats/Stand-Alone Greenhouse Controllers: Less Money, Less Flexibility
At the simplest, most budget-friendly level, a stand-alone greenhouse controller like a thermostat manages only one device with basic on/off functionality.
Thermostats lack precision and are difficult to calibrate. They can also give conflicting temperature readings when you use several in the same house or bay. This might result in wasted energy if, for example, your cooling and heating run at the same time.
Thermostats and stand-alone devices work fine in temporary structures or small greenhouses with only a few pieces of equipment to manage. But in most cases, their limitations tend to outweigh their lower cost.
Staged/Step-Based Controllers: Manage Your Climate One Step at a Time
Staged/step-based controllers move through a series of temperature-triggered steps. Groups of equipment activate or deactivate at each stage to cool or heat the greenhouse.
These controllers rely on input from one temperature sensor per zone to coordinate heating and cooling equipment.
While staged/step-based controllers offer more flexibility, features, and some remote access, they fall short of fully integrated control. They’re usually tied to one task, don’t use unified logic, and aren’t easily expandable.
Integrated Greenhouse Climate Control Systems: One Smart Controller Runs the Whole Greenhouse
An advanced greenhouse controller, also called a climate computer, brings all controls and equipment together into one integrated network. It decides what should run, when, and for how long.
Integrated environmental control systems can control nearly every greenhouse function and manage multiple zones, each with its own climate strategy.
You have remote access to monitor the greenhouse and make changes from your phone or computer. When something is wrong, the controller sends you alarm notifications.
Integrated controllers also provide valuable data, analytics, and predictive tools. These benefits often more than justify their higher cost.
Factors That Affect the Type of Greenhouse Controller You Choose
Several things influence which level of control makes sense and how deep to go with automation:
- Grower type
- Crop mix
- Operation size
- Labor
- Climate
- Structure type
Let’s look at three of these areas a little closer.
How Present Can You Be in Your Daily Operations
Automating a greenhouse is all about saving time and labor.
If labor is plentiful or you operate a small greenhouse, having a high level of control may not be worth it since someone can be on-site to manage things.
If you manage 50+ acres of greenhouses and labor is scarce, having a high level of control with remote access becomes more important.
Ask yourself: How much hands-on attention can my team or I give this greenhouse? The answer indicates how much automation you’ll need and thus what type of greenhouse control systems work best for you.
Don’t Discount the Weather
We can’t stress the importance of factoring location into your automation strategy enough.
Climate plays a big part in what systems you need to grow your crops efficiently, and how hard your heating, cooling, shading, and ventilation systems need to work.
A greenhouse in coastal California with mild summer weather, for example, won’t need the same level of tight control and automation as one in Denver, Colorado, where summer temperatures frequently swing from hot days to cool nights.
Match the Controller to the Structure
Low-cost or seasonal structures, such as cold frames or high tunnels, aren’t designed to support heavy or complex growing systems, so installing advanced climate controls is a waste of money.
That kind of investment makes more sense for high-value structures designed to last many years, especially if they’re initially built with automated systems, and more will be added over time.
If the structure you want can’t support the automation you need today and down the road, it’s not the right fit. You need one designed to scale as your operation grows.
The same goes for your greenhouse control system. If you plan to expand your greenhouse or add automated systems over time, choosing an expandable environmental controller is a smart move, budget permitting.
Choosing the right greenhouse controller isn’t always easy, but when it’s the perfect fit for your operation, everything gets a whole lot easier to manage.
If you’re figuring out your options for greenhouse controllers, we’re here to help you find the right fit for your operation. Contact us today.
This article pulls key insights from our “Greenhouse Automation Series: Pre-Automation Essentials” webinar. Watch the full session
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