Is this a frost pocket?

[dipper]

my second property basically ends up at the bottom of a ravine with some decent elevation change. I have already planted 5 apples here and another 5 crabs. I was talking to my neighbor the other day, who is kinda a hippie/ live off the land guy. He breeds and sells garlic comericially, grafts apple trees, etc. the zone maps appear to actually put us in zone 5a here. He told me I should plant zone 3 trees because the trees are gonna die, due to the cold air moving down the hill.
I don't think there would be that drastic of a temperature issue to kill the trees? Maybe more of a issue with frost and flowering, but I'm planting late bearing trees. Does a later bearing tree flower later? I want to add about 20 trees but I don't want to force trees in a spot and not see them produce.
This specific location isn't the bottom of the ravine, and I don't doubt cold air will be making its way down the hill. I generally don't have foggy trail cam pictures like I do on a food plot at lower elevation. Here is some pics, is this a frost pocket?

 

[dipper]

I get a ton of foggy picture in the food plot west of the black box. It's lower than the black box, and is clearly a frost pocket.

U can see the neighbors apples across the road. I'm about 10' lower than his apples. This is the guy who said his zone 4 apples died because of the cold. I don't see how it gets that cold to kill trees?

 

[dipper]

This is a pic of basically the box

Looking down the hill from the west, down to the proposed orchard. U can see its dropping elevation, but not super fast right here

North end, looking south, up hill. I'm only going to plant 2 rows of apples on the highest part of the plot. The rest will be kept as a food plot.

 

[dipper]

I am aware of frost pockets and never really considered this spot as one, until the neighbor got into my head. I'm not convinced he really knows what he's talking about? This is zone 5a technically, can there be that drastic temps to require a zone 3 tree?

 

[chummer]

Not sure about the frost pocket but late bearing does not always equal late flowering. I have been looking into the latest bloom times I can find and the drop times for the those apples are all over the place. The best I have found for both is Goldrush and Golden Hornet for crabs.

 

[Turkey Creek]

I am aware of frost pockets and never really considered this spot as one, until the neighbor got into my head. I'm not convinced he really knows what he's talking about? This is zone 5a technically, can there be that drastic temps to require a zone 3 tree?

Winter hardiness is a indication of ability to withstand the coldest temperatures for a growing zone. Has nothing to do with frost. If frost killed trees there would be a lot more dead trees in this world.

I am going to try and grow and graft some later blooming varieties this coming year.

 

[MA VT Flatlander]

In a few weeks when they are calling for low temps of around 35-37, check that spot if it has frost on the grass it's a frost pocket. I have apples in a low spot like that by the river here, it can be 36 on my wood shed and a frost in the field by the river. Some years I get froze out but usually have apples. Never had trees die from a frost.

 

[greyphase]

My take on a "frost pocket" would be in the ravine at the bottom of the hill. I could be wrong but if the trees are planted on the side of the hill I would think they would be OK as the cold air will flow past them to collect at the bottom. Articles I've read recommends planting on the side of a hill for that reason. Agree with Chummer a late bearing apple doesn't mean it's a late bloomer.

 

[chummer]

My take on a "frost pocket" would be in the ravine at the bottom of the hill. I could be wrong but if the trees are planted on the side of the hill I would think they would be OK as the cold air will flow past them to collect at the bottom. Articles I've read recommends planting on the side of a hill for that reason. Agree with Chummer a late bearing apple doesn't mean it's a late bloomer.

I am starting to think frost pockets can be much larger. My trees were absolutely loaded with blossoms this year, late and early bloomers. I have a handful of apples from all those blossoms. If I go 2 miles up the road in either direction the trees have a good crop. I go five miles and the trees are loaded. Is it possible I have that bad of luck to be in a 4 mile wide frost pocket?

 

[tooln]

I'm not really sure on the frost pockets but I know that it does not take a whole lot of elevation change for them to happen. When I'm out riding the bike I run across this all the time you'll hit a spot in the air just gets extremely cold with very little elevation change.

 

[deepsleep]

Interesting discussion. I, too, had a ton of blossoms but few apples this year. We did get a late frost, but I seem to have been hit harder than others locally. My property is in S. MI where it is flat, but I am bordering a large swamp with higher properties (maybe 10-20 feet higher) around me. I have been a bit concerned that I may be in a frost pocket. I will say that certain fruit trees have fruit every year, regardless. Kieffer pears, Shinko and Oympic Asian Pears, Centennial crabs and Yates come to mind.

 

[dipper]

He was trying to say the spot in the ravine makes it a different zone. I think it only get so cold, right. I can't see how you could possibly go from technically zone 5a to only be able to grow zone 3 apples?
He did bring up about how this ravine stretches over a mile north and south. I'm about 100 yards from rock bottom, because that's where the creek is.

 

[wiscwhip]

Keep in mind I am no apple expert, but I do know a bit about long term failures/disappointments with apple trees. IMO, this could be a frost pocket. Frost pockets/cold spots shouldn't be killing your trees, but microclimates can do strange things, so who knows. What is the issue with you planting Zone 3 trees, other than it limits your choices somewhat? Are they for personal consumption or for the deer? If strictly for deer, they don't care about variety, drop timing is more important to them.

I see the high ground in the topo and the accumulation of cold afternoon air on the east side of the high spot in relation to the "swamp/creek" as being a funnel for that cold air. It could quite possibly travel down that slope and the thermals could have enough flow to reach the area in question...see below.

 

[West Branch]

He was trying to say the spot in the ravine makes it a different zone. I think it only get so cold, right. I can't see how you could possibly go from technically zone 5a to only be able to grow zone 3 apples?
He did bring up about how this ravine stretches over a mile north and south. I'm about 100 yards from rock bottom, because that's where the creek is.

Hardiness zones zones are each 10 degrees with 5 degrees for "a" and "b". So, I think a frost pocket would have to consistently be 10-15 degrees colder to limit your apples by a couple zones. This link says that frost pockets can be up to 15 degree colder, if that happens enough times a winter, I think it would change the hardiness rating for that small area?
https://www.extension.purdue.edu/extmedia/ho/ho-203.html

 

[chickenlittle]

I think about a frost pocket being about air movement from a stream of cold air fleeing down hill (the thermal) interacting with the prevailing winds. The frost pocket comes when you get pooling of still cold air. What are the structures that direct the flow from both sources, thermal vs. prevailing? Is it being dammed up by something like the woods line at the bottom of a hill? Does a thermal channel suddenly widen and slow while being protected from the prevailing wind?

Is the cold air coming from the south/southeast and getting stopped by the trees? Does the swamp flow NE or SW?

 

[Bowsnbucks]

The weirdest episode of low-lying frost build-up I've ever seen was on an evening bow hunt in mid-October. I came out of a hollow and into a field that had a shallow ditch in it. As I approached the ditch, I couldn't figure what the white appearance of the ditch was. Ditch was about 2 ft. deep at the deepest. I got closer and thought I was seeing things. At first I thought some kind of mold had grown on the grass & weeds in the ditch. It was FROST !!! I stepped down into the ditch and was shocked at how cold it was in that ditch, but 2 ft. higher in the field it was probably 55 degrees !! It was a calm night.

I repeated the " step up- step down " maneuver 2 other times to make sure I wasn't nuts. That was the oddest occurrence of pin-point cold I've ever experienced. I don't know what that tells you guys about frost pockets, but I'd say Mother Nature has some odd tricks up her sleeve. I don't know if a blanket statement can verify just how cold air acts under some conditions. FWIW.

 

[dipper]

There is roughly 1900 acres that drains into 2 creek bottoms. These creeks bottoms share technically share elevation, since this 1900 acres is a bowl with a max high of 1100 feet.

The tree will actually be 170 yards for the bottom

 

[dipper]

There is some old standard trees 280 yards to the east. These trees have been producing apples pretty consistently.

The mature bucks like these apple trees, one did this by them last fall.

 

[Bowsnbucks]

From the aerial it looks like the location of the new tree(s) gets good sunlight. If you have trees right across the road producing, why not give it a try ?? Morning sunlight will keep frost to a minimum, if any forms. The other close producing trees would have ME planting a few to try.