I notice when I want to purchase some African violets for my collection or sell some of my plants in those transition months of Nov-Dec and March-April where the day temperatures are cool and the evenings are just above freezing (>32 degrees F), buyers and sellers alike request heat packs be used. The question I had was, is that really necessary? Considering shipping of chimera and regular African violets is usually a 3 day (72 hr) process, cannot in the worse case situation, African violets be maintained at just above 32 degrees Fahrenheit (0 degrees Centigrade) for 3 days? Is there really any damage done to the plants? I decided to do a little experiment.
I found a volunteer plant. I had a nice Yukako chimera African violet in bloom that would do well. I was so confidant in the outcome (as my hypothesis was that at about 37 degrees for 72 hours no effect would be noticed) I had no qualms about using a Yukako. I also obtained a small temperature monitoring device that I set to take the temperature every 5 minutes for the duration of the 72 hour experiment. Below is an image of the plant bloom and plant with measuring device just before it was placed into the refrigerator.
The plant and monitoring device prior to placing them in the refrigerator (below).
Plant and monitor are place in the refrigerator.
The door was closed and not opened for 72 hours. I used 72 hours since that is the typical shipping time. So what was the outcome? What did the plant look like? Can African violets survive temperatures for a 72 hour period near at 37 degrees F?… …I was not certain exactly what to expect but confident my assumption that only minial plant damage would occur. I had in the past, in Chicago grown African violets outside under shade well into fall without any issues. Below is a chart of the temperature that was monitored every 5 minutes for the 72 hour period. As is evident the temperature was stable at 37 degrees F during the experiment.
Below is the plant after being exposed to 37 degrees F for 72 hours. Not looking good. The leaves were wilted and limp, even though the soil was moist, and general color was a brownish green.
After the plant was returned to it’s place in the plant stand the plant continued to deteriorate and it became evident that 37 degrees F for 72 hours thoroughly did the plant in.
The question now becomes, what is the coldest temperature above 37 degrees F that an African violet can be maintained at for a 72 hour period without damaging or destroying it?