Can apple grafts that are bagged get too hot?

Hello,

My father-in-law has been grafting apple trees and found information about bagging grafts with plastic bags to retain moisture, and improve graft success.  

I had never heard of this technique, but I must admit that the grafts that he covered with bags are definitely doing well. The bagged grafts seem to be much more advanced than the grafts which are un-bagged.

I was wondering how the heat and sun will affect the bagged grafts.  Our weather has had some extreme temperature fluctuations with it snowing one day and then being in the mid 80's a couple of days later.  I think that those bags have to be retaining a lot of heat. Will the bagged grafts be too hot when the outside temperature is in the mid 80's?   I'm sort of worried that the grafts exposed to the direct sun will be cooked.  

It would seem best to remove the bags now that it's warmed up, but the temperature seems to be on a downward trend again. It's been a strange spring.  It wouldn't surprise me if it snowed again before summer.
We live in Pennsylvania.

Thank you for any replies. Have a great day!
Regards,
Tim

i'd be more concerned that leaves grown in a high-humidity bag might not deal with drier air/wind well. but it could get too hot too. if they're growing out, why not remove the bag? are the actual grafts wrapped with something inside the bag?

greg mosser wrote:i'd be more concerned that leaves grown in a high-humidity bag might not deal with drier air/wind well. but it could get too hot too. if they're growing out, why not remove the bag? are the actual grafts wrapped with something inside the bag?

I was wondering about the humidity too.  The bags are dripping with moisture inside.  When I was a kid I had one of those miniature terrariums that came as a prize in a cereal box.  The seeds grew really well and I opened up the terrarium for just a little while. My seedlings died in only a few hours. Lesson learned.  

It's always amazed me too how a plant can get beat around by the wind all day,  while the very same type of plant (started inside) will wilt and die if you sit it out in half a breeze without protection.

I think I might ask my father-in-law to cut slits in the bags to slowly acclimate the grafts back into the real world.  

Thanks for your input.  I really appreciate it.
Regards,
Tim

I did an experiment this morning.  I used a chunk of wet 4x4 to simulate a tree trunk with moisture and put it in the sun with a thermometer.  I then covered the 4x4 and thermometer with a clear plastic bag .  The difference between the just air and being sealed with a bag was about 25 degrees.  79 degrees without the bag and 104 degrees with.  I guess of the 90 degree day the temp inside the bag must have been at least 115 degrees.  There was also a good amount of wind blowing today which wasn't blowing on the 90 degree day.  I don't know if this would remove any heat from the bag or not.  Seems like we might have a solar cooker /steamer going.

when does your father-in-law plan on taking the bags off?

greg mosser wrote:when does your father-in-law plan on taking the bags off?

That's a really good question Greg.
Hopefully, as soon as I can convince him that they might be a bad thing. I definitely can't argue that the bags seemed his scions leaf out earlier.   I think that I'll try to convince him to make some new slits in them each day and then remove them after some amount (?) of time.  The condensation in the one bag that I looked at was pretty heavy.

Would anyone have a guess of how much heat a scion would be able to tolerate?

It’s too hot in Florida for bags in the sun. We use paragon grafting tape for that purpose.

They can take about 125 degrees