CropDev Version 1.1 – Software for Timing Cut Flower Rose Production


Authors: Neil S. Mattson and J. Heiner Lieth

Plant Sciences Department

University of California, Davis






Purpose of CropDev software

            This software program is intended for growers of cut flower roses.  It can be used to help growers in scheduling and temperature adjustment for their crop.  The information described below is intended for the professional rose cut-flower grower who produces roses commercially by timing for specific dates (for example: Valentines Day). The software tool will run on computers using Windows 95/98/NT/2000/ME/XP.


Mathematical basis for the CropDev software

            This section includes technical information that you don’t need to have to use the software tool.


            The basis for this software is that there is a linear response between temperature and the rate of rose stem development.  That is, the higher the greenhouse temperature the quicker rose stems will grow and be ready for harvest.  The information contained in this document and within the software is extracted from rose development research by Dr. Heiner Lieth and his team at the University of California, Davis (see references below).


            This software uses the concept of heat units (also known as degree days or thermal units) to calculate how quickly rose flower stems develop.  For roses heat units are calculated as the temperature minus the “base temperature” (Tb); this difference is multiplied by the fraction of the day represented and then summed over time.  Tb is the temperature below which development does not occur.  For example, if the one-day average greenhouse temperature is 18.5 C, the number of heat units accumulated on such a day would be 18.5 C – 5.2 C = 13.3 heat units.


            If negative numbers were to occur as the differences, then these are added as zero, otherwise the roses would be calculated to be moving backwards, which they don’t do.  For example, if the day temperature in the greenhouse is 15 C for 12 hours; and the night temperature in the greenhouse is 4 C for 12 hours: then the heat units accumulated during the day time is (15 C – 5.2 C) × (12 hours ÷ 24 hours) = 4.9 heat units; and the heat units accumulated during the night time is (4 C – 5.2 C) × (12 hours ÷ 24 hours) = -0.6 heat units, BUT since this is a negative number this is turned to zero.  So the total heat units for the 24 hours period is 4.9 (day time) + 0 (night time) = 4.9 heat units.


Developmental stages of rose flower stems

            The CropDev software is used to time a flush of flower shoots – this flush is initiated by cutting/pinching back plants or bending stems (abbreviated CT).  During developmental a typical rose shoot then goes through the following stages: Bud break (BB), First leaf unfolding (L1), Visible bud (VB), Last leaf unfolding (LL), and the stage where the flower bud is deemed to be harvestable (HV).  An illustration and description of these events is shown in the table below.


Stage CT – stems are cut back/pinched or bent to initiate a cycle.

Stage BB – bud has reached the length of 1 cm and is clearly viable

Stage L1 – first true leaf unfolding (red circle); the vestigial leaf, not a fully developed leaf with leaflets, doesn’t count  note this on the right shoot (yellow circle)

Stage VB – the flower bud is just barely visible (red circle); the picture on the left is taken prior to VB and on the right just after VB.

Stage LL – last leaf unfolding (note the leaflet is beginning to unfold)

Stage HV – ready for harvest – the sepals are reflexed from the flower bud


Disclaimers and known issues with the software



Known Issues



            Click on the link below to download the software (it will be downloaded as a .zip file).  Find the file you saved (  Then right click on the file and choose “extract all” (if you have older Windows software you will need to install zip software).  The windows extraction wizard appears, click on the “next” button.  Choose the location (directory) where you would like to extract the files – save it to a place you can locate later (for example: c:\My Documents\RoseTiming\).


Download version 1.1C (begins in degrees Celsius)

Download version 1.1F (begins in degrees Fahrenheit)


            Once the files are extracted, you should notice **five** files: “instructions.doc” and “instructions.pdf” which are the instruction documentation you are reading; CropDev1.1.exe, this is the software program to run; HUParms.csv, this is the database with heat unit set points that the software program will use; “twoyearC.txt” or “twoyearF.txt” this is an example of a temperature data file.


            You can create a shortcut to the CropDev1.1.exe program on your desktop by right-clicking on the CropDev10.exe icon, then select “Create a Shortcut”.  You can now drag this “Shortcut to CropDev1.1.exe” to your desktop (or anywhere else you’d like).



What the software calculates

            The software uses a database that includes the number of heat units required to reach each developmental event – this is a set of parameter values.  For each variety of rose you will use a different set of parameter values.


            The user specifies a certain date that they wish for a developmental event to occur (for example: harvest (HV) to occur on February 9, 2006).  The software program uses the parameter values for the certain variety and projected greenhouse temperature and calculates the dates when the other events should occur.  The grower can use this information in several ways:

  1. Use these calculated dates to plan when to initiate a flush of growth.  For example, given the HV date of February 9th and a projected temperature, the program tells you the date that cutting/bending (CT) needs to take place.  The grower can ensure this action takes place on the appropriate date.
  2. Determine if the crop is on track.

·        A grower can monitor say 10 representative rose shoots throughout development.

·        The grower can determine the average date the shoots reached a developmental event.

·        Compare the actual date to the date scheduled by CropDev.  If the shoots are behind schedule – the grower can determine if they need to raise the temperature to push the crop; if the shoots are ahead of schedule the grower may determine that they need to lower the temperature to hold back the crop.

  1. Determine the greenhouse temperature needed to produce a crop on a specific date.

·        Let’s say you just harvested on a crop on February 9th; now you want to see what temperature you would need to time this crop for Easter; in the program.  You would set February 9th as the new CT date and adjust the temperature panels until you find an appropriate temperature where the crop would be ready in time for Easter.

Loading a parameter database

            Now let us start using the software.  You will start running the software by double clicking on the CropDev1.1.exe icon.  If this is your first time running the software you will see a message indicating that the Calculator history file does not yet exist and that a new file will be created; click on the “OK” button.  Then, you should see a window like below:



            Next we will open the parameter database.  If this is the first time you are using the program, then this will be in a file called HUParms.csv.  Click on the “Open a Parameter File” button (red circle in the picture above).  A window will pop up prompting you for the location of the parameter database.  Find the folder you extracted the program to (for example: c:\My Documents\RoseTiming\), for “File name:” choose the file HUParms.csv and click on the “Open” button.  You should now see a window similar to below:



            Note that you can only select a few varieties; you can add parameter values for your own varities into the database using your production records (see section below on the Calibration Tool). 


            In this example, let’s say we are timing ‘Fire and Ice’ growing under winter conditions; select its parameter values for by double clicking on the variety ‘Fire and Ice’ (red circle above).  The program automatically switches to the Timing Calculator tab (window below).  We are now ready to develop our first crop schedule.



Developing a crop schedule

            Let’s develop a schedule for ‘Fire and Ice’ with a target harvest date of February 7th , 2006.  Start by clicking on the dot in front of HV (red circle above) – this selects the harvest as our fixed date, all other dates will be calculated relative to this one.  Now fill in February 7th, 2006 as the harvest date – you may do this by manually filling in the blank next HV as 2/7/2006; or by clicking on the down arrow next to the date – this brings up the calendar utility where you can scroll through months to select the appropriate date as in below:



            Notice that the time of 12:00 PM is listed next to the target date.  In this version of CropDev the user cannot change the time for the target dates, the software assumes it happens around 12 noon.


            Now that we have set the target harvest date – we need to specify the projected temperatures in the greenhouse during each developmental stage.  Let us say temperature will be 22 C during the interval from cut to bud break (CT to BB); then 20 C through visible bud stage (intervals BB to L1 and L1 to VB); and then 18 C for the final two intervals (VB to LL and LL to HV).  Go ahead and change the interval temperatures in the average temperature box as below (you can do this by typing in the appropriate number or using the up and down areas next to the temperature).



            Now click on the “Calculate dates”.  The software has now calculated the dates that the other developmental events should occur as in below.



            The software calculated that the crop flush should begin on December 15th, 2005 for the average harvest date to be February 7th.  The projected dates for the other events to occur are all listed.  The grower can make sure the crop is on schedule by observing some representative shoots over time – on January 15th half of the representative shoots should have visible buds.  The times of day are not particularly important at this point; they are provided so that you can see how close a calculated date is from the next or previous date. For instance, if an event is calculated to occur at 11:50 PM then that is only a few minutes away from being the next day.


Saving the crop schedule into Calculator History

            Once you have performed a calculation, you may choose to save this information into the Calculator History.  The Calculator History allows you to reload the saved calculation into the Timing Calculator.  The calculator history will store the cultivar specific parameter values, and the dates and temperatures used in the calculation.  Once a calculation has been saved to the Calculator History you can reload this data into the Timing Calculator where you can modify various parameters and then recalculate the dates.  (This may be useful, for example, if you have new temperature values for some of the intervals, and you would like to see how the new temperatures influence the projected target dates.)  Also, you may export the data from the Calculator History to a comma separated value file (*.csv) which could be loaded into a spreadsheet program.


            To save a crop schedule that you have just calculated into the Calculator History, first, enter any comments that describe the calculation into the comment field (noted by the red arrow in the picture below).  Then click on the “Save calculation to Calculator History” button (yellow arrow below).



            You can view the Calculator History by clicking on the “Calculator History tab, you will see a window similar to below:



            Each time you save a crop schedule into the calculator history a new record is created.  The record stores the following information: record number, the comments the user entered, the date the calculation was performed, the target developmental event, the dates that each event were calculated to occur (some of the events will be blank if there were not part of the calculation), the average temperature during each of the developmental stages, and the parameter values used in the calculation (variety, base temperature, and the heat units required for each stage).  You will need to use the horizontal scroll bar to view some of this information.


            To save the calculator history to a *.csv file, click on the “Export Calculator History” button.  A save window will appear and you will be prompted for the file name and location where you would like to save the history.


            You can load a record back into the Calculator, so that you can modify some data and conduct new calculations.  To do this, click on the line that corresponds to the record you wish to load.  This line will be highlighted.  Then click on the “Load Record into Calculator” button.  (If a temperature data file was used in the original calculations, this is not stored Calculator History.  Instead, it will store the average temperature during each developmental event.)


            Finally, if you are sure you no longer wish to save a record in the calculator history you can delete the record.  To do this, click on the line that corresponds to the record you wish to delete.  This line will be highlighted.  Then click on the “Delete this Record” button.  A window will appear to ask if you are sure you wish to delete the record, click on “Yes” or “Cancel”.


Additional Features

temperature graphs

            There are some additional features of CropDev to point out.  Notice there are two graphs on the bottom.  The first graph represents the temperature during the course of the production cycle that was entered in the “Average Temperatures” box.  This is useful especially when you are using a temperature data file (described below) and want to make sure the program has read in the temperatures appropriately.  The second graph represents the number of accumulated heat units during the production cycle.  If average temperature is low you’ll notice that relatively less heat units are accumulated per day (a gradual slope); while if temperature is high you’ll notice a steep slope (relatively more heat units are accumulated per day).


convert between Fahrenheit and Celsius

            Our initial demonstrations were in degrees Celsius – if you prefer to see these numbers in degrees Fahrenheit you may click on the “Convert temps to F” button (red circle below).  You can click on the “Convert temps to C” button to back to degrees Celsius.  CropDev also has a built in function that will convert temperature between F and C if an unsuitable temperature is detected – in the average temperatures pane, if a temperature greater than 40 is entered it is automatically assumed that this is in degrees Fahrenheit; if a temperature less than or equal to 40 is entered it is automatically assumed this is in degrees Fahrenheit.  The same assumption is used for the Day temperature in the “Greenhouse temperature calculator” (described below), and for Night temperature values greater than 35 are assumed to be in Fahrenheit.



greenhouse temperature calculator

            In our first scheduling exercise we entered the temperature manually.  If you have projected greenhouse temperature in terms of day and night temperature set points you can use the “Greenhouse temperature calculator” on the right side of the panel (as shown below).



            In this example, we have specified our day temperature as 23 C, our night temperature as 18.5 C, and our daylength as 13 hours.  The calculator determined the average 24-hr temperature was 20.9 C.  Let’s say we want to use this as the temperature during our last two production intervals (VB to LL and LL to HV).  You could manually change the temperature in the “Average Temperatures” box.  Or you can automatically use this temperature by clicking on the 3rd circle for the last two intervals (red circle in picture below).



using a temperature data file

            Let’s say you have a data file with daily temperatures in your greenhouse throughout a year.  You can use these temperatures in the CropDev software.  Your data file needs to be in the following format:

·        the data is in two columns

·        the first column lists the day/time

o       the number in front of the decimal point is the day: 1=January 1st, 365=December 31st (on a non leap-year year)

o       if you have hourly averages for January 1st, the first column could simply list “1” for the first 24 values (the CropDev programs then reads that there are 24 values for day 1 and averages them for a daily average temperature)

o       or you may list the specific time of day after the decimal point (as in the example below) – with 24 hours in a day 1:00 AM is 1÷24 which = 0.04167

·        the file needs to be saved as a tab delimited text file (if you are creating this in Excel, select the Save as type to be: “Text (tab delimited) (*.txt)”



            To use this data file for specifying temperatures click on the “Load data file button”.  Here choose the sample file included with the software “twoyearF.txt” (or if you prefer Celsius “twoyearC.txt”).  Set the “Beginning year of data file:” to be 2005.  The “Day range of data:” should now list that there is day for days 1 through 731 – when you have more than one year of data you should continue the numbering from the first year – so if January 1st, 2005 is day 1, December 31st, 2005 should be day 365 and January 1st, 2006 would be day 366.



            Now let’s use this data file to plan a crop where the target harvest date is December 20 th, 2005 and variety is ‘Kardinal’.  Remember to select HV as the fixed date by clicking on the dot in front of HV, then click on the drop menu next and use the calendar to select December 20th, 2005 (as below).



            Now in the “Average Temperatures” pane you need to specify the temperature for three intervals (CT to BB; BB to VB; and VB to HV) – for each of the three intervals click on the middle dot (as in the red circles below) this means the temperature will be specified in the data file you loaded.  If you had forgotten to already load a data file, you would be prompted for the temperature data file.



            Now click on the “Calculate dates” button.  Notice that the CT, BB, and VB dates were calculated so as to achieve harvest on Dec. 20th.  You’ll notice that you can verify the temperatures used from the data file by looking on the average daily temperature graph – because were specified through a temperature data file rather than manually typing in the average temperature during an interval, that these changed daily during the production cycle.



            A final note in using temperature data files, is that you need to be careful to include the appropriate range of dates especially when your production schedule overlaps two years (for example, your production schedule for Valentine’s day may begin in 2005 and extend into 2006).  In this case the “Beginning year of data file” needs to be set to 2005 and your temperature data file would need to include some temperatures that take place in 2005 (day number < 365) and temperatures for some dates in 2006 (day number > 365).  Let’s say you have a data file with average temperature in a greenhouse over the past 9 years and you want to use average values of this for projected temperature.  To be able to use this for the Valentine’s day example: you first use average temperature by day for days 1 through 365 in the file, then copy the same temperatures for the same dates in year 2, except now the days are 366 through 731.


calculating dates for previous or future crop cycles

            Given your harvest date (for example, February 7th) you may wish to calculate when the following flush of shoots would be ready.  You can do this by clicking on the “Set CT=HV, Calc”.  This will set February 7th as the next cut day (CT) and then calculate the dates of developmental events for the next production cycle as in the window below.



            The new harvest date is calculated to be April 2nd, 2006.  Let’s say you would like the second production cycle to be ready for Easter (April 16th).  The harvest date may be a bit early for Easter sales.  You can adjust the temperature lower during certain intervals to see if it could be feasible to hold back the crop till Easter.  As an alternative you may decide that greenhouse temperatures will be higher during this cycle so you could wait a couple weeks before bending plants back to initiate the cycle.  In this case you would set CT to be say February 21st and then adjust temperatures until you arrive at an appropriate harvest date.


            The “Set HV=CT, Calc” button works in the opposite direction.  It will set the harvest date to be the cutting day from the current cycle and calculate when the previous production cycle should be initiated.


selecting a variety from a drop down menu

            In our first scheduling example we selected the parameter set for ‘Fire and Ice’ by double clicking on it in the ‘Parameter Database’ tab.  Another way to select the variety to schedule is to use the Variety drop down menu in the ‘Timing Calculator’ tab.  Click on the down arrow across from the listed variety (red circle below), a list of the other variety appears – here choose Kardinal.



            If you look at the parameters for Kardinal you will notice that it has parameters determined only for Cut, Bud break, Visible bud, and Harvest (window below).  Consequently, you can only select one of these stages as the target date and when you are defining temperatures you do this for the intervals CT to BB; BB to VB and VB to HV (second window below).




Developing parameters for your own varieties using the Calibration Tool

            The real strength of the CropDev software is that you have the ability to create a set of parameters for your own rose varieties and growing conditions.  To do this you will need average dates that some of the developmental events occurred and average greenhouse temperature during this production cycle.


            The more detail oriented you can be in developing parameter sets the more precise the CropDev software will be in scheduling.  We make the following recommendations:

·        You should develop a parameter set for each different variety you use. 

·        The tool is more precise if you develop different parameters for each season.  We have noticed that the number of heat units required during production can be different for winter versus summer conditions for the varieties we work with.  This may be due to light levels, stem quality, or the effect light has on heating up plant tissue.  We recommend that you create parameter sets for different seasons and compare them to see how different they are.

·        It may be more precise to develop unique parameters for each greenhouse range.  Depending on how uniform your facility is, each range may have its own microclimate (light/shading levels, degree of temperature control, etc.).\

·        We have found that parameter sets calculated for a crop that was pinched/cut to initiate a cycle could be used when the same variety was bent to initiate a cycle.  You may wish to test whether or not this is the case for your own varities.

·        Again, it should be noted that we cannot guarantee the accuracy of the software.  Users should test the software themselves and check everything against their own experience.


            Let’s say that you produced a new variety during fall/winter 2005 and you would like to create a parameter set for it.  You made the following observations:


            First, start by click on the “Calibration Tool” tab.  Next, fill in information for “Variety” and any additional “Comments” (as below).



            Now enter the dates that the developmental events occurred and the temperatures.  Click the box in front of CT to place a checkmark, adjust the date to 10/29/2005.  Click the box in front of BB and adjust the date to 11/10/2005.  Now adjust the “Temp during interval:” between the CT and BB lines to be 20 C.  Click the box in front of VB and adjust the date to 11/27/05.  Adjust the “Temp during interval:” between the BB and VB lines to be 21.5 C.  Click the box in front of HV and adjust the date to 12/20/2005.  Adjust the “Temp during interval:” between the VB and HV lines to be 18 C.  This should now look like the window below.  (Note the picture on the right side of the window below.  You can click on the tabs for a picture of each developmental event.)



            Now we are ready to perform the calculations.  Click on the “Calibrate” button (red circle below).



            You will notice that the number of accumulated heat units from cut to bud break, visible bud, and harvest has been calculated.


            Finally, you can add these values to the parameter database by clicking on the “Copy, Save, and Return” button.  You will be prompted to resave the database – you must save the parameter database to be able to retrieve the values the next time you run the CropDev software.  You will notice that this new variety is now available to be used from the drop down menu in the “Timing Calculator” tab or can be selected from the “Parameter Database” tab (as below).





            If you are experiencing software errors, please contact Neil Mattson, at  Please do the following:


            If you have questions regarding how to operate the software please make sure you have read this documentation completely before contacting Neil Mattson.


If you are using the CropDev software we are interested in getting feedback from you.  Please email Neil Mattson, at  Include the term ‘CropDev’ in the email subject line.  In particular we are interested in learning the following:



Mattson, N.S. and Lieth, J.H. 2006. The effect of temperature on year-round development of rose shoots initiated using cutting or bending.  Fourth International Symposium on Rose Research and Cultivation. September 18-22, 2005. Santa Barbara, California. Acta Horticulturae. submitted.


Pasian, C.C. and J.H. Lieth.  1994. Prediction of flowering rose shoot development based on air temperature and thermal units. Scientia Horticulturae. 59:131-145.


Pasian, C.C., and J. H. Lieth. 1996. Prediction of rose shoot development: model validation for the cultivar ‘Cara Mia’ and extension to the cultivars ‘Royalty’ and ‘Sonia’. Scientia Horticulturae. 66:117-124.




The initial CropDev software tool was developed by Heiner Lieth.  The research that the tool is based on was funded by the Joseph Hill Foundation, Roses Incorporated and the International Cut Flower Growers Associations; with some work supported by the EISG/PIER program funds from the California Energy Commission.


The current version of CropDev was developed by Neil Mattson and Heiner Lieth with support from the International Cut Flower Growers Association.


CropDev version 1.1, copyright 2006 by Neil S. Mattson and J. Heiner Lieth. All rights reserved.