I think those trees will handle 26 and still have a crop left, maybe even no damage. But I’d be out there covering them just in case. Mine are in about the same stage and they’re predicting slightly warmer. It’s going to be March and April here that we’ll get damage. I expect to have to cover mine at least 4 times to make a crop.
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What stage are blooms/fruit at the most sensitive to freezing?
The more advanced the flowers and fruit the more sensitive they are to freezing. But even a month from now when there are clearly formed fruits it takes about 28F to start causing damage. There are charts out there maybe someone will post a link.
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Derby,
As Fruitnut mentions, the charts show blooms/fruit get more sensitive to cold as development progresses.
The exception might be when fruits get a certain size, the curve goes back the other way (i.e. they gain some slight frost tolerance). I’ve not read this, but I have a friend who told me once his peach grove got some bad frost very late in the spring, and the fruitlets survived, when he really didn’t except them to.
I suspect this phenomena may be partially due to the fruitlets start to gain some sugar as they start to grow, which would act as an antifreeze.
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im moving in 2 weeks to the new house so I dont have much ambition to try and save these or i would do something. the other trees arent near as far along.
My cherry bushes looked like they were two thirds bloomed out this morning. It is forecast to be 23 here tonight. This is the earliest they have ever bloomed so they probably have a snowballs chance that they will make any fruit this year. Oh well , maybe a few will make it , enough for the grandkids to eat a few.
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Derby,
It’s pretty bad here too. The news I watched this morning projected some pretty cold temps in the morning here.
I sprayed copper on the peach trees yesterday to try to perhaps get some frost protection. Probably a waste of time because there is so much cool spring weather to get through.
I don’t think the cold tonight will hurt the buds because we aren’t yet at red calyx, but I’m pretty sure we’ve got a lot more cold coming.
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I agree, my peaches are holding off right now but it won’t take much to put them at the point of no return. In your opinion does it take below freezing temps to completely stall bud development? just looking at the forecast and trying to figure out how the trees are going to react.
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We are at bud swell and some green calyx here. In my observations, just about any temps below 40F will stall development at any stage of development (even bloom).
The bad news is that I’ve seen peach blooms come out and then get stalled because of cool weather. The blooms aborted in that case, even though they never got frosted.
It’s my theory that for some reason peach blooms need to keep advancing at a certain pace, or they will die. I don’t know why that is. Perhaps they can’t self-pollinate very well if it’s too cold?
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I have been thinking about covering my plums when we get the dips in temperature. Is it adequate to cover with plastic and put a couple of light bulbs inside? Any advice is appreciated.
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I think that has always been hotly debated. I’d like to know too. I’ve heard that covering plants without a light source is a waste of time. In the old days I remember dad would cover tomatoes and roses during late spring frosts. he would use anything he could find on hand from grocery bags to bed sheets.
Many of my stone fruit trees are loaded with blooms this year for the first time and I’d like to at least get something.
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I have a couple of large cages that I used to protect my blueberries from birds that would fit over the plums without touching. I was thinking about putting a light bulb inside and then covering with cheap plastic.
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My experience is that once the tree develops a good canopy of leaves that provides some protection from the late radiation freezes. I’d think that’s more likely than increasing sugars. But this is mostly speculation on my part.
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My theory is that if you have something low to the ground, like a young tomato or pepper, and cover it without a light source, the warmth coming up from the ground and trapped by the cover will give you some protection from a light frost lasting a couple hours. However, for a tree, where the blooms/fruitlets are several feet off the ground, the little heat radiating up from the earth is unlikely to overcome a temperature drop to say 25. In that case Bills strategy is the way to go.
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I think most fruit growers will enjoy this article that discusses types of frost protection and effects of cold weather on fruit trees Principles of Frost Protection
Last year my Flavor Delight bloomed earlier than the other fruits, right before a killing freeze. So much for that, I thought.
But a dozen or so late blossoms opened after the freeze and I did get fruits from them.
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Last year I had three Romeo cherries in full bloom. It got down to 28, which was quite a bit lower than the forecast. Nary a cherry.
Yes it is in my experience as long as the heat source is adequate for the size of enclosure and temperature. On a small tree, say 4x5ft a light bulb might work. On a bigger tree I’ve used 750 watt heaters. I tend to overkill so any heat source can help. I’d agree that just covering helps little or none.
It’s know in apricots that if the pollen tube stalls out due to cold the pollen can die before it reaches the ovary. Same could be true of peaches.
At earlier stages of bloom, before full bloom, cold weather but above freezing for a day or two can draw water out of the developing flower and increase it’s hardiness. So hope for a couple days of cold before a damaging freeze.
I’ve been thru freeze damage dozens of yrs. My experience is that it’s seldom one freeze that takes out everything. Usually it’s a cumulative effect of two or more freezes separated by days or weeks. But then our bloom is spread out much more than up north.
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In regards to copper preventing damage it can be effective but many people try to spray copper the night before a freeze which is ineffective. Copper must be applied long before the cold weather arrives. See this article http://ceventura.ucanr.edu/Com_Ag/Subtropical/Publications/Frost/Foliar_Sprays_for_Frost_Protection_of_Young_Citrus_and_Avocado_-1995/.
This part of article should be of particular interest
" For some years, it has been known that bacteria residing on cold-sensitive plants initiate ice formation. The ice formed in or on plants spreads rapidly, causing mechanical injury. Copper-containing sprays that are applied 10 days before cold weather, kill off these bacteria and allow enough time for their decomposition. By controlling the ice -nucleating bacteria, tests have shown temperatures may drop 2-4¡ F below critical levels without plants showing damage.
For the past four winters, we have been working with four materials that have shown promise in freeze trials on several crops in other states. To evaluate their relative efficacy, we have been applying Kocide¨, a copper spray which controls ice-nucleating bacteria; Anti-Stress 2000¨, a plastic film used as a antitranspirant; Frost Shield¨, another antitranspirant; and Frost Guard¨, a systemic/contact nutritional spray. Two field and two cold chamber trials have been monitored."
The article made menote the strength of the tree was one of the most important factors.
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Let me add one more note about the absolute insanity of the weather this year. It is supposed to be 80 degrees here today. EIGHTY…IN FEBRUARY!!! Yesterday I walked by my garden and was blown away to see a full sized asparagus tip ready to pick. I have 7 trees with full blooms on some or all of their limbs, and pretty much all my trees have swelled up buds except for some apples and persimmons and a couple other odd trees. But within a week almost all my trees will probably be in bloom.
If you are thinking that because TN is in the “south” this isn’t THAT strange, I’m here to tell you that it most certainly IS. I’m on the KY border and February is very often our coldest month. Some of our biggest snows have been in March, and you can never be sure frost is over until the first week of May (with rare exceptions even for that).
The odds that we won’t have any temps below 27 (or whatever the kill point is for blooms and tiny fruit) is almost ZERO! In fact, even though its 80 today, tomorrow night is supposed to be 29!!! Its just crazy.
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