Unpacking greenhouse crop steering and RTR
Source: HD.com
"Plants do not respond to isolated values of temperature, light, or humidity, but rather to the balance between the energy they receive and the energy they consume to grow, respire, and produce." © Canna.biz RTR over time The scientific link between radiation and temperature has been on the record since the 1970s, but RTR as a practical tool has only entered the working vocabulary of growers in the last decade, driven primarily by Dutch researchers and by the evolution of climate sensors, control systems, and the data analysis layer that ties them together. This approach is important because it helps maintain the plant in energy balance, adjusting sugar production to the energy actually available, whether coming from sunlight, supplemental lighting, heating pipes, or air movement generated by fans." © Canna.biz Operationally, RTR functions as a temperature adjustment factor based on available radiation, expressed as a relationship between accumulated radiation and average greenhouse temperature over a given period, typically 24 hours.
The expected accumulated radiation over the next 24 hours, drawn from a local weather service or a greenhouse-specific forecasting model, is 1100 J/cm². On the assumption that 1°C is added to the average greenhouse temperature for every 1000 J/cm² of accumulated radiation, the target average temperature for the day works out to roughly 19.1°C, the 18°C baseline plus 1.1°C reflecting the radiation received.
"Even air circulation systems without active heating can deliver significant amounts of energy to the crop, often in the range of 30 to 40 W/m², depending on air speed and the temperature difference between the air and the leaf." That convective energy directly influences leaf temperature, transpiration, and plant metabolism, all of which feed back into the total energy balance shaping the plant's physiological response. Footprint calculations take center stage at Dutch horticulture sustainability event Airmix concept now usable year-round, with introduction of active dehumidification Activating plant stress physiology for more efficient greenhouse production Related Articles Unpacking greenhouse crop steering and RTR Chilies suit Belgian tomato growers group’s diversification plan Hungarian strawberry harvest at 7,000 to 7,500 tons “We’ve always been growers, with a deep commitment to our category partners” U.S.
Why this matters: For operators, this is a water-management story. The useful signal is that direct substrate measurements can help cut drain loss materially without giving up yield or fruit quality, which is exactly the kind of controllable efficiency gain a facility can build on.
Frequently Asked Questions
Why does substrate sensing matter in free-drain strawberry systems?
Because drain percentage tells a grower what already happened, while substrate moisture and EC data show root-zone conditions directly. That makes it easier to cut water loss without guessing.
What is the operator takeaway from this trial?
If the thresholds are understood well enough, growers can reduce drain water materially while protecting yield and fruit quality, which makes sensing an operational tool instead of a reporting tool.
