This is when you hope your microclimate helps, not hurt you.
A few weeks ago, it was predicted low at 29 F. Weatherunderground said it was 29 F. My apricot was at late stage of blooming. It should not have had damage. Well, 99% of my apricots got freeze kill. You never know.
3’’ - 5’’ snow predicted tonight and tom. not supposed to get above freezing tom. with 35mph gusts. glad everything is still sleeping.
I was wondering what you had coming your way! Dislike button !
I pretty much know that cold flows downhill, and that’s where most of my plants and trees are.
@Ahmad @Susu @PharmerDrewee Covered up all my figs and tomatoes. Ran one of those pipe warming cables for the figs that are in the middle of the yard. My Tam Kam persimmon is going to have to tough it out… hopefully that’s not a mistake.
Forecast is predicting a low of 36°F tonight and 37°F tomorrow but last frost my measured temperature was nearly 9°F degrees lower than the forecast. Good luck everyone!
@applebacon did you spray with copper recently? If you did it may buy you some cold hardiness. If you killed the bacteria that help form ice its likely you are ok (see blossom blast) Here is a critical temps brochure for blossoms so you know the temparature losses occur
CriticalTemperaturesFruitTrees.pdf (2.4 MB)
i agree but snow in mid may isn’t unheard of here unfortunately.
THIS IS WHAT THE FREEZES HAVE DONE TO ME SO FAR…
I have waited 5 years for this Apricot to bloom and when it finally did…
APRIL 14
MAY 7
THEY DO CALL IT GROWING NOT HARVESTING… NOW I KNOW WHY
MIKE
my condolences.
Mike,
I can feel your pain. I hope some will survive. A few of my apricots have survived the April freeze until tonight. Not sure if any will survive after this weekend’s cold blast.
I’m guessing the weather is going to do my plum thinning for me.
I’l saying a prayer for the rest of you.
Scott
Good luck everyone! I hope we all make it through with no or minimal losses. It’ll be a stressful night. I’m glad my work day has me exhausted or I might not be able to sleep well knowing my poor plants could be freezing to death.
Brought most of my figs inside and put some under trees. They have too much growth and this is the third time going in and out. Took me close to two hours to do this. Good Luck everyone!
Peculiar……………MSN just raised our forecast so it’s staying above freezing.
Ya’ think we can believe them?
Good luck everyone. I have two layers of row cover and a sheet covering my strawberries and a sheet over two of blueberries. I am going to get up at 2 when the rain is forecast to stop and turn the Xmas lights on that I wrapped around those blueberries and between the strawberries. Low of 33 so hoping for the best for the trees.
Nice explanation of what is about to occur in my backyard…
Radiation Frosts A radiation frost is probably the most common during “cold sensitive” times in
Washington and is the easiest to protect against. Almost all frost protection systems/methods
available today are designed to protect against radiant-type frost/freezes. Radiant frosts occur when
large amounts of clear, dry air move into an area. There is almost no cloud cover at night. During
these times, the plants, soil, and other objects which are warmer than the very cold sky will “radiate”
their own heat back to space and become colder and colder. In fact, the plants cool (radiate)
themselves to the point that they can cause their own damage! The plant tissues which are directly
exposed to the sky become the coldest.
These radiation losses (as much as 1-1.5 million BTU/ac/hr) can cause the buds, blossoms, twigs,
leaves, etc. to become 2-4°F colder than the surrounding air which radiates very little of its heat.
The warmer air then tries to warm the cold plant parts and it also becomes colder. The cold air
settles toward the ground and begins a laminar flow towards lower elevations. This heavier, colder
air moves slowly (“drifts”) down the slope under the influence of gravity (technically called
“katabatic wind”), and collects in low areas or “cold pockets”. This drift can also carry a
considerable amount of heat out of or into (from higher elevation heating activities) an orchard or
vineyard.
The general rate of temperature decrease due to radiative losses can be fairly rapid until the air
approaches the dew point temperature when atmospheric water begins to condense on the colder
plant tissues (which reach atmospheric dew point temperature first because they are colder). The
heat of condensation is directly released at the point of condensation, averting further temperature
decreases (at least temporaily). Thus, the exposed plant parts will generally equal air temperature
when the air generally reaches dew point. At the dew point, the heat released from condensation
replaces the radiative heat losses and further air temperature decreases will be small and occur over
longer time periods. A small fraction of the air will continue to cool well below the general dew
point temperature and drift down slope.
Thus, having a general dew point near or above critical plant temperatures to govern air temperature
drop is important for successful, economical frost protection programs (which is, fortunately, often
the case). Economically and practically, most cold temperature modification systems must rely on
the heat of condensation from the air. This huge latent heat reservoir in the air can provide great
quantities of free heat to an orchard or vineyard. Severe plant damage often occurs when dew points
are below critical plant temperatures because this large, natural heat input is lacking and our other heating sources are unable to compensate. There is little anyone can do to raise dew points of large,
local air masses.
Concurrent with the radiative processes and in the absence of winds, a thermal inversion condition
will develop where the temperature 50 to several hundred feet above the ground may be as much as
a 10-12°F warmer than air in the orchard. Springtime temperature inversions in central Washington
will often have a 3-5°F temperature difference (moderate inversion strength) as measured between
6 and 60 feet above the surface. Many frost protection systems such as wind machines, heaters and
undertree sprinkling rely on this temperature inversion to be effective.
41F with a 14F dew point here… not good. …winds have come way down/skies are clear.
After supper I went out in a coat and toboggan and put about 6 tarps on the strawberries. I got a big one from down in the barn, plus a few big sheets. So, my patch is about 80% covered, much better coverage than before. Took about an hour to do the job.
The temp at 10pm is 43 uphill/41 down the hill, and has held steady for a few hours. Prob because we have very light (on radar anyways) rain, and clouds. Hope it sticks around for a few more hours, but I know it’ll eventually clear out. I think if it stays above 40 until midnight, we might get just a minimal freeze.
Since most of my tree fruit is already gone, I hope all the berry plants do well. Some rasps (Prelude) are just now blooming, the blacks aren’t, gooseberries have buds on them, but can’t say for sure they’re blooming. They are at the most risk being furthest down the hill. I might go down there and drape a sheet over the big one before bed.
Good luck, especially to those in central and west PA, forecast models are showing some mid 20s for tonight.
… but the state change from water to ice would yield a lot more, wouldn’t it?
