11 January 2022
During a grower webinar in November 2021, hosted by US trade magazine Greenhouse Management and Canadian control systems supplier Argus Controls, greenhouse controls consultant Jeff Woolsey addressed the relationship between using fully integrated control solutions and key concepts for greenhouse operations, such as return on investment, plant quality, efficient use of resources and product tracking.
These days every decision you make about managing your greenhouse and the crops you grow in it depends on data – and the more data you’re able to draw on, the better and more consistent your decision-making is likely to be.
Until recently for many, ‘data’ meant a grower’s accumulated experience, alongside any written records kept for future reference.
But modern integrated greenhouse controls to capture and use data from a vast array of sensors – from weather stations and temperature and humidity sensors to fertiliser dose settings and vent or screen positions – so have the game-changing ability to archive, and help you use, detailed records on everything that can have an impact on your crop.
The implications for improved decision-making and planning are almost as important a benefit from such systems as the more efficient and effective day-to-day climate control they deliver, according to US greenhouse systems engineering consultant Jeff Woolsey.
“We hear a lot about artificial intelligence but you don’t need it to make your control system smarter,” he told a grower webinar in November. “Integrated control can be a game-changer in smaller as well as large facilities. Whatever size nursery, it will bring the same advantages.”
Whether you’re introducing integration by upgrading an existing control system or investing in a new one, there are three key points to consider, he says.
First, integration means the system has to be capable of basing its control decisions on inputs from a range of sources. “The most obvious is an on-site weather station and you should not skimp on that as the system relies on weather data more than any other input,” he says. “But there are others you might not immediately think of, such as flow rates in the fertiliser dosing system.”
Weather stations, glasshouse climate sensors and so on can be linked to the controller via a wireless set-up – potentially offering more flexibility for positioning – or through ethernet or similar cable network. The heating systems, vents and screens being controlled can be connected in the same way.
Second, the system should base its decisions on variable inputs and targets rather than simple static set points, which Woolsey says makes it respond faster and more appropriately in changeable weather conditions, such as when clouds are rolling past on a sunny day. The system can forecast, and so make ‘pre-emptive’ changes, which keeps the environment more stable as well as reduces wear and tear on equipment such as vents and screens.
A further advantage of using variable inputs and targets to control the system is that it builds in an element of ‘self-correction’. For example, says Woolsey, if your fertigation dosing system uses multiple heads and one fails, it can automatically adjust the others to compensate as well as trigger an alert.
Third, you should be able to access and manage the system remotely over the internet, from your smartphone or laptop. “Remote access is a major advantage,” says Woolsey. “You may already be able to get an alarm if something goes wrong at 2am but remote access means you can see how serious it is and whether you need to go in to deal with it.
“You can also change set points remotely, or the way equipment such as a shade screen is being used, or check the performance of different zones over the past few days, without leaving your office.”
When it comes to judging the value of moving to an integrated control system, Woolsey says top of the list is the improved crop quality resulting from its ability to maintain the environment close to optimum. “That includes, for example, delivering a reliable and verified average daily temperature using energy as efficiently as possible; provision of fertigation at reliable and verified EC and pH using the least amount of fertiliser or acid stock possible; and being able to monitor water quality to flag up and control disease risk,” he says.
“Integrated control will give you a consistent high-quality product season after season.”
Alongside that is energy efficiency – a term Woolsey prefers to energy conservation, as a small increase in energy input can often greatly improve crop quality or cut growing times while some energy conservation measures do the opposite.
Then there’s the value of the archived data which is collected. As well as being fed back into the system to fine-tune its control decisions, the data is also available for the grower to analyse for troubleshooting and for planning. “You can troubleshoot the whole nursery from your desk,” says Woolsey.
“And when it comes to planning new projects the data can really help pin down specifications. It means you make better decisions, with less guesswork and less risk that equipment will be over- or under-sized.”