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Germany

The past days we´ve had some alternating weather conditions, sometimes cool and wet, and then again warm for a couple of days. My daily measurements indicated that, upon weather having cooled down, the pumpkins kept growing at good rate for another one or two days before growth rate dropped. Then, when it had warmed up again, pumpkins seemed to require an induction period of one or two days before they reached their initial growth rate. Did others also observe this phenomenon, which I call FRUIT GROWTH HYSTERESIS? Is this just a phenomenon caused by cool pumpkins (it might take a while before they cooled down, and also takes a while before they reach higher temperatures when days are warmer), or does light have a much more important influence (so that "warm" pumpkins in greenhouses would show the same behavior when there are some cloudy days to drop growth rate after the second dark day and recover to high speed after an induction period of one or two sunny days)?

8/5/2011 5:51:31 AM

Jericho Vermont

I have observed this in Northern Vermont where I grow and we try to combat this with numerous quilts and blankets. We have had a morning low of 60 degrees F. only 8 mornings this summer with the rest colder even as low as 48 degrees F. I have also talked with other growers regarding temperature fluctuations and BES in the past. It seems that after a real cold night followed by a warm day we have more of a tendency to see splits. We also observed once growth slows it does not come back in the first warm day and even have had some pumpkins slow down to an almost stop regardless of what the temps are after the cold snap.

8/5/2011 12:50:32 PM

South of Buffalo

I have noticed this same thing.
In our heat wave mid late july night temps were low 80's high 70's. Then on 7/26 low temsp went to the low mid 60's. My growth measures dropped from 30-33#/day to 10-12#/day. This continued for about 6 days and after increased water and kelp drench/foliar the volume picked up. Was at 32-35#/day for 4 days until today where is dropped to 25#(another cool night last night) I have been using only a sheet with several t shirts over the fruit.

8/5/2011 1:03:21 PM

Midway, UT

We deal with the same thing in Colorado. The plants don't like dealing with the big swings in temperatures. Our overnight lows are about 59 degrees and highs at about 91 this time of year. I figure we lose about 2 pounds a day on average because of it.

8/5/2011 7:01:28 PM

Rhode Island

weather ---- the great equalizer

8/6/2011 7:33:52 AM

South Bloomfield, Ohio

Amen to that pap.

8/6/2011 8:03:21 AM

Germany

Thank you all for your comments. Looks as if temperature was the most important factor in that case, rather than the amount of sunlight.

8/8/2011 3:07:39 PM