Potential damage from extreme spring frost in the northeast


I’ve been watching forecasts for the polar vortex about to thrust into my domain. Fruit trees in my orchard seem to be at about the third stage in the above graft. Now I just have to hope ;they don’t change much in the next 4 days when the worst is expected and we could see temps below 20.

Who knows, maybe we get the perfect freeze to accomplish thinning.

I’m wondering if it may damage my apple grafts but guessing it won’t matter. .

I’ve been watching that…looks like peaches and plums will be costly at market this year!

Ughh. I’ve got a low of 15 forecast for Tuesday night. And each day that low has trended lower.

Relevant temperature of damage info for anyone needing it from PSU:

And from MSU (with pictures!):

Here, I’ve only had damage when winter temps are so cold to damage dormant fruit buds, or when tender blooms present themselves to spring frosts.

I’ve never had temps cold enough to damage closed/partially closed blooms in the spring. I think, by far, most of the risk in the spring occurs when blooms are open, or past open, but then again I’ve only lived in the Midwest.

Good luck to everyone in the NE. We have another possible freeze event here for tomorrow morning.

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This is a quote from Bob Vance (it was under the Nadia thread, he was kind enough to answer my question).

" I was about to post this on Alan’s thread about the upcoming freeze(s). But, since you ask, I’ll put it here instead:

Starting Sunday night, I’ve got 27, 24, and 21 forecast. I’m thinking about getting out a few tarps and maybe a light bulb. I really want to protect my Nadia and the pluots.

Maybe some apricots (Early Blush in particular) as well. They don’t live long enough for me that I don’t want to give up any productive years."

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11F predicted on Tuesday. Nothing bloomed yet though, so it should be OK

It’s 75 now. Plum is post bloom and peach is in full bloom. Low of 24 predicted for Tuesday night and my microclimate is always a few degree lower than forecast.

If I string Christmas tree light to the tree branches and use the tarp cover the top of tree, does the tarp have to be closed up at the bottom? Some of my peach tree has diameter of 20 feet, I won’t be able to close it.

Also, can mosquito torch work if I stick a few under the fruit tree?

Sara, I would watch the NWS weather as I have found it to be pretty good on the lows - they are forecasting for farmers. Philly is predicted for 26F now on that. I am currently forecast at a low of 28F. Usually these lows will come up a few degrees over the next few days as well. But not always…

If the forecast is still looking bad on Sunday it will be time to get out the plans for tarps and lights. Any tarp can help a bit if there is a heat source inside it.

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Thank you, Scott! I will follow the forecast for the next couple of days. By the way, can I also use old blankets to cover the trees?

Anything that blocks wind and holds heat will help.

I have only one or two peach blossoms opened. Most of my plums vary from green tip to tight cluster but I have 3 jefferson plums and 1 green gage (might be bavays) that have been in full bloom for 3 days with bees buzzing all over them. My other gages have barely woken up. I’m hoping, since they are likely already pollinated, that they might be able to withstand a few degrees colder. Probably wishful thinking. I think our forecast low over this spell is 23. The jeffersons blooming early really surprised me, I think they even bloomed before the ornamental redbuds. I got fruit from one of them last year and it is definitely a gage type plum, not mislabeled or anything.

Two years ago we had freezes twice that got down to 24 on my property- well after petal fall. I don’t know the exact temps in the trees but I still got a very good peach, nectarine and plum crop. The only problem was peaches and nects that got to the size of golf balls and then stopped growing and started to rot- but that seems to be fairly unusual although it’s happened in my orchard twice after late hard freezes.

Charts are useful, but I don’t believe they are as precise as you might think and that in the real world there are variables we (and science) don’t know about. I once got a very hard late frost where the peach varieties that had already lost their petals were all that produced fruit- go figure!.

If I tell that one to a scientist in the field they probably wouldn’t believe it. Probably wouldn’t believe the story about frozen fruit growing for over a month after the event either. The first time it happened the Cornell fruit guru suggested it was because of hot weather (tell that to a Georgia peach grower) the last time it wasn’t particularly a hot year- but I didn’t believe him the first time either.

Science and its methodology is extremely useful- just not infallible, especially in the hands of its human interpreters, even if they have doctorates on the subject.


Here’s what I’d say Alan, the charts are more precise than your reading of what the temperature is in the fruit zone.

I’ve seen that where the leaves on early blooming trees protected the fruit. Especially on big, old, never pruned trees with a very thick canopy. Again a question of what is the fruit temperature.

Of all of my trees the cold snaps have really affected my peaches. Walking around the orchard yesterday I could just barely touch a bud and it would fall off of the tree. Lots of that and on one apricot as well. Not a good peach year for me and I’m in 7a. It is the commercial grower like Olpea, that is my concern. I just have some land with trees for my pleasure. Oh my.


If any of you people have KDL, I’d sure spray it. Besides, what do you
have to lose.

That makes sense, but is just a theory. I don’t see how leaves can insulate and if they aren’t positioned to trap heat from the ground it doesn’t satisfy my curiosity- trees were pruned and well managed and there wasn’t much leaf development on the trees just a few (I’d say 3 or 4) days ahead.

Explain to me how the data can take into account things like radiated heat from the ground and a handful of other possible factors. I would like to know the methodology but I doubt the research is that thorough and/or definitive.

Not that I’m not hugely appreciative of the research involved and not that it isn’t more informative than anecdotal observation.

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The leaves can offer some protection from a radiation freeze. That’s what happens on a still night with clear skies and the upper parts of the tree are directly exposed to the roughly -40F temperature of the sky. If there are leaves above the fruit that can offer some protection. Leaves would offer little to no protection during an advective freeze which combines high winds and below freezing air.

Maybe what I should have said about the freeze damage charts is that during a freeze the researchers no doubt had better equipment to measure temperature near the trees in question than we typically have. We rely on a thermometer usually near our house or the nearest weather station. A degree or two makes a big difference at times and is very difficult to accurately measure.

Yes, that’s why I mentioned I wasn’t sure about the exact temps in the trees which is always the case with most growers. My equipment consists of a single cheap digital thermometer sensor. My terrain is fairly steep with lots of rock outcrops so I know that temps vary somewhat throughout the orchard.

My point was really only that we growers can’t know from a chart exactly what will happen in our orchards so just hope for the best until you know differently.

Anticipation of catastrophe can be worse than than the catastrophe itself. Just ask my wife, who thought someone had died when she heard the scream I made a half hour ago when Accuweather reduced its estimated low from 19 to 11 (or was it 13?). No one else, including the gov site has followed suit, so I have returned to optimism.

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13… Yikes!!! That sounds awfully unlucky to me. I hope that doesn’t happen.