1. 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
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.
2. The GPE plant balance RTR
Go to "modules" and then to "GPE plant balance RTR"
You will now see an overview of the department(s). Click on the relevant department for which you want to see the graph and overviews.
You will then see a screen with various options. Here you can find a number of graphs, overviews and manual entries.
You can set the module via "settings overview". Read in section 2.2 how to set the parameters. After setting up the module, you can find the result of the calculation in the graph "RTR point graph" and in the "week overview".
2.1 The RTR point graph
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, see section 2.2. 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.
2.2 The settings overview
In the settings overview, the set strategy can be read and changed. As an example for the explanation we take a base temperature of 16.0. This means that when there is no light at all on a day, the minimum temperature of 16°C must be achieved. The RTR target stands for the number of degrees one wants to go up per KJ/10 mol/m². This can be set using the hand tool.
Is it possible to work with the PAR sum?
It is possible to work with the PAR sum (if you have these measurements). For this, the PAR sum must be connected instead of the radiation. Please contact your LetsGrow.com Implementation Manager or the LetsGrow.com Service Desk if you are interested in using this measurement.
2.3 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.