MSU launches petunia scheduling tool for greenhouse growers

A team of Michigan State University researchers teamed up with PanAmerican Seed to develop a spreadsheet to help greenhouse growers predict the effect of temperature on flowering time for 15 varieties of Wave petunia.

The team performed experiments to quantify the effects of temperature and photosynthetic daily light integral (DLI) on flowering time and characteristics of 15 Wave petunia cultivars. The goal was to generate temperature-based flowering time models for more predictable greenhouse scheduling, according to MSU reports.

Based on controlled greenhouse research experiments, researchers developed mathematical models that predict flowering times at average daily temperatures of 54 to 75 °F.  Those equations were then incorporated into a Microsoft Excel program that allows a user to enter two temperatures to estimate time to flower (see Figure 1).

In addition, the program predicts the effect of changing the DLI between 5 and 14 mol•m²•d¹ on flowering time. Flowering times are from transplant of a 288-cell plug grown under long days and assumes plants are finished under long days.

Examples of the crop predictions for three varieties are shown in Table 1. Increasing temperature, increasing the DLI, or both, accelerate flowering, but the values depend on the specific variety.

“We hope this tool can be used by growers to improve the predictability of flowering, and to predict the consequence or raising or lowering the temperature to accelerate or delay flowering to meet a desired shipping date,” said Dr. Erik Runkle, one of the MSU researchers, in a press release.

The program can be downloaded free at the MSU Floriculture webpage and on the PanAmerican Seed webpage.

Charts provided by Michigan State University.

Fig. 1. The Wave Smart Scheduling tool can help growers predict the effect of temperature and daily light integral on flowering time of 15 different Wave petunia varieties.

Table 1. Estimated number of days from transplant of 288-cell Wave petunia plugs grown under long days until first flowering. Timing is from the Wave Petunia Smart Scheduling Tool and assumes long days are provided during the finish stage.