I think it would depend on the size of the tree and how you hang the tarp. I don't think that blocking light is any problem for a few days. The problems I would foresee, especially with your forecast, is the winds. If that tarp isn't secured perfectly, it could do a lot of tree damage!!!

If covered with a tarp, how do you expect the flowers to be pollinated?

curious where you are .. are you pushing the zone for peach?? .. because this sounds like what i went thru in MI .. year after year ...

some years i had great crops.. other years ... not so much ... and it wasnt worth trying to beat ma nature ....

what is a 'good sized' tree??? ... im wondering if its all worth it ...

i agree with the wind issues ... damaging the tree might set you back next year ...

you might also wonder.. with temps that cold.. what level of pollination you will get ... will the workers be out taking care of that ... and if they arent ... then the tarps are useless ...

the default.. would be that you remove the tarps every day.. and replace every needed night.. which could be a PIA for a larger tree ...

im also curious what kind of heaters you have ... dont forget the cost benefit ratio ... these could end up being very expensive peaches .... it would actually be cheaper.. in the long run.. to just go to the orchard and buy a crate of them ... if you needed them for pies.. jelly.. etc ...

i realize pro orchards do things differently ... all this is just a dude with a couple plaything fruit trees in his yard ...

love your name ... good luck

ken

Agree that covering w/plastic alone doesn't work -- tried it on several tender items & frost came right through it, killing new growth. Heaters under the plastic might help...

Oof! I wrote this post, and just noticed that - thanks to an overzealous filter - all the reply notifications went to my spam folder!

I want to thank everyone for your input. I'll answer the questions y'all asked in another post.

I decided to go ahead and cover the tree. Thanks to the help of my spouse and a helpful teenager, we got the tree halfway covered with a tarp and anchored to the ground with ratchet straps and screw-in ground anchors.

It was a wild week for weather - we had a couple days of horrible winds, three straight nights in the low 20s, and then - to cap it all off - a snowstorm that dumped 7" of wet snow.

On the coldest nights, I ran a tank-top radiant propane heater under the tarp. I also ran a heavy extension cord and put an electric heater under the tree.

For more passive heat, on the day before it got cold I raked the mulch back and ran a sprinkler around the base of the tree, per recommendations I found on an extension website; the intent was for the bare, wet ground to warm up during the day and then exude its heat at night. I also placed a few trash cans under the tree and filled them with hot water late each evening.

It was all a bit of a PITA, but it seems to have worked! The tarp was basically destroyed but ultimately did its job. We lost some twigs and flowers on the periphery, but the tree overall is doing well.

We looked at the tree today and it's well-covered with little baby peaches!

@gardengal48 (PNW Z8/9): "If covered with a tarp, how do you expect the flowers to be pollinated?"

I worried about that too. There were a lot of bees on the flowers, so I waited as long as possible to cover it, only doing so at dusk the evening before the bad weather was scheduled to hit. I figured the bees wouldn't be pretty inactive for the few cold days we had.

The tree being approximately 10-12' tall, the tarp basically was just draped over the top and staked down, so I imagined any enterprising pollinators that were out and about could get in and do their work.

@ken_adrian Adrian MI cold Z5: "curious where you are .. are you pushing the zone for peach??"

I'm just south of Omaha. We're zone 5b, but more like a 6a a lot of years, especially in the past 10-15 years or so. The tree is located at the back corner of the yard, next to two 6' wood fences, which I'm sure helps create a microclimate. "Garnet Beauty" is a "Redhaven" sport variety, and seems to do well in colder climates.

"what is a 'good sized' tree??? ... im wondering if its all worth it ..."

The tree is about 12' tall, give or take. Probably about 20' at its widest. The tarp was 12' x 24' and wound up covering about half, maybe 2/3 of the crown of the tree. We anchored it with ratchet straps and screw-in ground anchors. It worked well enough.

"im also curious what kind of heaters you have ... dont forget the cost benefit ratio ."

I had a couple of full 20lb propane tanks that had been sitting around unused for quite some time (I get them free occasionally through my work), so it wound up not costing me much except some sleep to keep the tree warm enough. It's now got a bunch of little peaches on it so there's a happy ending, I guess. :)

@nmfruit - I'm awfully stubborn and just had the one tree, so I decided to give it a go. It was indeed in full flower when the cold snap hit, and I've lost most/all of my crops to late frosts in the past, so I decided to try the wildly impractical setup I describe a couple posts above here.

I've done other things in the past like you have, like heaters, watering deeply, trashcans full of hot water beneath, etc, but those were just for single cold nights, not multiple nights, and the presence of a south-facing wood privacy fence on two sides of the tree undoubtedly helped those times (and this time too).

In the event, we wound up with three nights in the 22° range, with heavy frosts on two of those nights. I'm pretty sure that without intervention I'd have lost a great deal of my potential harvest.

To see just how effective my efforts were, I had a disused wireless thermometer floating around the house, so I put batteries in it and put its sending unit out in the canopy of the tree. My goal was to keep the temp under the tarp at over 27°, and I was able to achieve that mostly. I was evidently successful enough that the tree set a bunch of fruit!

Now all I have to do is keep the accursed Japanese Beetles off them; they unfortunately arrived here a few years ago, and are most active *right* at the end of July, when the fruit are ripening.