Introduction
Optimal growth can be achieved, among other influences, by creating the right temperature - light balance on a daily basis. Depending on the climate zone and region, the relationship between the average temperature and PAR sum or light sum can vary significantly from day to day. To obtain maximum production and quality, the plants need a constant relationship between temperature and light. But how can you check this? The Plant Balance Module provides insight into your realized temperature and light balance (RTR).
The desired ratio of the average temperature (consumption of assimilates) to the daily light sum (production of assimilates) can be defined by entering two values:
- The desired base temperature
- The desired temperature rise per 1000 J/cm² or 10 mol / RTR target - °C / (kJ or 10 mol/m²)
With the help of the cultivation advisor you can determine which target values are optimal for the desired situation. These values only need to be entered the first time and can be changed if necessary.
Setting up the Plantbalance
The Plant Balance uses an RTR calculation. The RTR uses the light sum (also known as DLI), the 24-hour temperature of the greenhouse, a base temperature, and a target RTR.
RTR target - °C / (kJ or 10 mol/m²)
The number of degrees Celsius the greenhouse temperature (over a 24-hour period) may rise per 10 mol PAR light or 1000 joules.
Base temperature - °C
The 24-hour temperature used as the starting value for the target temperature - °C (24 hours)
Light sum
This is the amount of light measured over a 24-hour period, which can be either PAR sum - mol/m² or radiation sum - J/cm².
Greenhouse temperature
This is the measured 24-hour temperature available on MyLetsGrow.
Graphs and overviews
The RTR calculation for the plant balance can be displayed in various ways.
This can help to gain a better understanding.
The different ways are explained in more detail below.
The parameters can be easily set via “settings overview.” After setting up the parameters, you can find the result of the calculation in the “RTR point cloud” graph and in the “weekly overview.”
The RTR scatterplot
The GPE plant balance RTR calculates and presents the desired and realized RTR in different ways. One such way is the RTR Point graph. This shows the realized greenhouse temperature versus the light sum in the form of a point cloud. The light sum is on the horizontal axis and the temperature is on the vertical axis. Each point represents one day within the selected time period. The selected time period is displayed in the top right corner.
In the chart, some points are highlighted in bold. The last seven days are in bold to give insight into the realization of the last seven days. The other dots represent the days before the last week, back to 30 days. If the climate has recently been adjusted, you can quickly assess whether further adjustments are necessary. In addition, a red line is visible. This red line is the trend line through all of your points. So this is your realized light-temperature ratio. The formula of this line can be requested by clicking on 'analysis options' (gear wheel at the top right of the graph) and then choosing 'trendline formula'. The trend line can then be read in the top left corner. The last number in this formula is equal to the base temperature and the number before that is the increase per 1 KJ/10 mol/m². The graph also shows a green, pink, orange and red line. The green line indicates the desired greenhouse temperature in relation to the light sum. You can enter this in the settings overview. The pink and orange line are one half RTR more and one half RTR less. Ideally, all points are between these lines. The more of these points are close to the green line, the more the climate is in balance. With this information you can immediately see if the greenhouse temperature is too high or too low and make faster adaptation to the climate, even before you see a reaction on the plants. If the bold dots are around the green line, no further adjustments are needed. You have already achieved a constant relationship between temperature and light sum.
The settings overview
The settings overview is a table showing the set parameters.
In addition to viewing the set parameters, they can also be easily adjusted.
Clicking on the manual entry button opens a new tab where the parameters can be easily entered.
The weekly overview
We also have a weekly overview. Here you can read the results of the past 7 days, including the realized greenhouse temperature and the target greenhouse temperature; what you can achieve based on your realized RTR.
Temperature setting - DayNight (4 weeks)
The target temperature graph shows the actual 24-hour greenhouse temperature over the past 4 weeks. In addition to the realized greenhouse temperature, the target cabinet temperature is also shown, with bandwidths of 0.5°C warmer and 0.5°C cooler.
The target cabinet temperature per day is a daily temperature that calculates the target greenhouse temperature based on the set parameters. The target greenhouse temperature per day is calculated based on the actual light sum for the day. The target greenhouse temperature per day is determined based on the combination of the base temperature and target RTR.
This graph makes it easy to look back over a longer period.