Best temp for tomatos

colokid(5)July 17, 2011

I still have 10 tomatoes in pots in my little green house. Mostly grow outs from my own cross. GH is in shade during the top of the day, but in afternoon the swamp cooler kicks in. It is keeping temp at 84 degrees max. Temperature at night goes to 60 regularly. Should I raise it a bit? or is 84 about right? I seem to have complete control over the maximum temperature and the cooler provides a nice strong breeze when it is running.

Out in the raised bed, my stupice it starting to blush, about time to get a fresh tomato.


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dan_staley(5b/SS 2b AHS 6-7)

84 is fine. Mid-90s is not.


    Bookmark   July 17, 2011 at 7:26PM
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The man who grew tomatoes in 3 large greenhouses around here tried to keep his 90 degrees or just under if I understood it right. He let it bump 90 to conserve on power costs some. Up to and just over 90 with temps around 60 of a night and he had good fruit set. So 84-85 should be great. Many say fruit set drops off depending on the variety around 92-93 degrees. Some varieties set well up into the mid 90's. Like I stated earlier I'm seeing fruit set with temps around 100 or over during the day. And a few varieties are starting to stick out. Personally from my experience I feel that the lows of a night are more important than the highs of the day. A subject that everyone has an opinion on and has been debated longer than the politicians has our national debt. Jay

    Bookmark   July 17, 2011 at 11:23PM
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One thing to keep in mind with a greenhouse is the higher humidity.

Before ventilation, obviously there is high humidity. Even after the vents are open, inside air is likely to be a bit higher. Turn on the swamp cooler and it is all evaporation cooling - nice, humid cool air!

Given Jay's experience with and information on humidity and fruit set: that may suggest keeping a lower temperature than higher.

Many plants are comfortable with 85F. We'd throw water on everything if the temperature looked like it might climb above that. There's that humidity thing, again!


    Bookmark   July 18, 2011 at 1:01AM
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Actually it got up to 90 Sunday. Outside was 103 degrees. Humidity is still very low inside, even when the cooler is running. Guess I will leave the settings alone. thanks for the comments,

    Bookmark   July 18, 2011 at 9:28AM
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I thought after I posted I should of stated that with a swamp cooler the humidity can cause clumping of the pollen. So the cooler the temp within reason is best.

Kenny I would imagine you are fine. My friend who had the greenhouse turned some form of bee loose in the greenhouse to help with pollination. So shaking the plants might help. Also the breeze from the cooler should help. Jay

    Bookmark   July 18, 2011 at 3:42PM
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