From

Location

Message

Date Posted

Mount Prospect,illinois

What daytime outside temp would it be best to open the cloches so the plants dont cook? Seems it gets pretty warm inside even when the outside temps are in the 50's. I figured it might be good to have an idea before actually planting.

4/17/2007 7:59:01 AM

Nikiski, Alaska 99635

Depends on whether it is cloudy or sunny. Temperatures in the 50s can cook your plants. www.leevalley.com sells some great heat sensitive gas charged cylinders that require no power. Made in the UK and fully reliable. Adjustable knob on the botttom to provide for lower or higher opening and closing temperatures. Have some pictures of these Dave on last years grower diary and one photo on this years diary. Good Luck in 2007.

4/17/2007 11:03:36 AM

Menomonie, WI ([email protected])

Also depends on what interior humidity levels are.

4/17/2007 1:01:08 PM

Indiana

I am way off the norm, but I like to let them get 110º F before I open them up. This does cause them to wilt, and like Shannon said thats 110 degrees at high humidity reducing evaporation. That allows them to take more heat. The abscisic acid produced is not beneficial, but at such a small size I think is completely insignificant at a more mature size. I have accidentally taken them up to 136 degrees(temp in the shade) in the full sun with 100% humidity with no lasting ill effects.

I only do this for the first week or so. I think it helps toughen up the plants for later in the summer. Like I said, most will vehemently reject what I do as acceptable so take what I say as an opinion.

Tom

4/17/2007 1:34:31 PM

Mount Prospect,illinois

Tom,
You have the experience with these things for sure but i think i would cook them if even tried to keep it closed on a warn sunny day. I am simply looking for a rule of thumb general daytime temp in which i would open them prior to going to work. The gas charged cylinders is interesting but way too advanced for what i am doing.

4/17/2007 6:24:12 PM

Deer Park, WI

Beach you goof ball what the H are you doing letting em get that toasty. I like your idea of torching them in preparation for brutal summer heat. Lets hope there's some merit to that idea.

My devil's advocate 2 pennies- Photosynthesis begins to shut down when you get into the 90's. Temps that high begin to degrade the enzymes necessary to photosynthesize and metabolize nutrients. I'd have to believe that 136 (good lord) would all but nuke the poor suckas. I dont think a day or so would hurt em bad, but a weeks worth of this stress for sho would have detrimental effects.

4/17/2007 8:38:26 PM

No Place Special

I take Beachy's side on this issue. I like to push mine up to 100* durring the day. (I think i may have taken this idea from Beachy some time ago.... hey all, Beachy is not as stupid as he looks!) This I do mostly for my state fair plants. I have found that these warm temps produce plants that can handle the heat MUCH better when the hot summer gets here. Serious, works for me. I dont get nervous about the temps until the hoop gets over 110* deg. Matter of fact mine got to 116* today before i got the fan out to blow in some cooler air. As for me.... I open the huts door all th eway in the morning and close them in the evening. as the season gets warmer I cut some additional windows that can allow more air flow. Keep in mind a sunny day...even an unseasionally cold one will heat the hoops easily over 100* without ventilation. The sun is key.

4/17/2007 10:03:24 PM

Phoenix, AZ

Absolutely let them heat up and harden. Heat Shock Proteins (pro-tee-ins if your my old philosophy professor) are produced and do harden the plant to both extremes of heat and cold. Also, photosynthesis does shut down but this is for only a portion of the day remember.

4/18/2007 12:53:12 AM

Rhode Island

a lot depends on the size of your greenhouses. the large ones will take a bit longer to get to the extreme heat and the small ones cook real fast.
we always err on the side of caution. if in doubt about the eather leave them open.
no need being at work wondering if your plants are being cooked.
heat stress only sets the plant back.

4/18/2007 7:02:22 AM

Georgia

Ive seen some growers that cut four or five flaps in the hoops and just keep them open all the time. Not to hot or to cold is this a good idea or just less work????

4/18/2007 1:22:35 PM

Mount Prospect,illinois

Thnaks all for the info. I dont trust myself to do what Frantz and Beachy do. I think i will simply open them up before i go to work unless it is going to be overcast and cold. The flaps idea may be an option too but then i would be getting back into the "am i allowing enough air flow?" while i am at work thing.

4/18/2007 1:51:34 PM

Oswego, New York

Do what Skip from Maine told me, "just have fun".

4/22/2007 9:12:59 PM