DC Area frost warning

Shogun610

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There is another frost warning up here 2nd night for Pennsylvania Lehigh , N Bucks , N Montgomery and Berks as well .
 

penumbra

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I hit 31 degrees but no frost and no damage apparent. I have over 50 ficus and other tropicals outside, and see no damage. It was 34 at 5 am, 31 at 6 am but 37 at about 7:30 am. This is for Front Royal at the northern end of the Shenandoah Valley. My buddy in Luray, 29 miles south of me had heavy frost.
 

Paradox

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Yea we had frost advisories the last 2 nights and again for tonight
 

Carol 83

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We've had frost the last couple of mornings. Nothing new here, we had snow last year late April.
 

rockm

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Woke up to relatively heavy frost this morning. Went out and sprayed the trees' tops with water. Water insulates the leaves from the frost. Air temp was 38 or so. Frost is on exposed areas, open grass, house rooftops, cars on the street, etc. Under relative cover of leafed out trees, etc., no frost.
 

Jrmcmich

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Woke up to relatively heavy frost this morning. Went out and sprayed the trees' tops with water. Water insulates the leaves from the frost. Air temp was 38 or so. Frost is on exposed areas, open grass, house rooftops, cars on the street, etc. Under relative cover of leafed out trees, etc., no frost.
Did you spray the night before to limit or in morning after frost already there? I know Wednesday night here will potentially have same issue.
 

Dav4

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Did you spray the night before to limit or in morning after frost already there? I know Wednesday night here will potentially have same issue.
I'll spray the night before right before bed, and as soon as I wake up if it's cold enough... but if there's a chance of frost, I get my good trees under cover the night before.
 

WNC Bonsai

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We unexpectedly hit 35 last night so I guess I will find out just how low a Brazilian rain tree can go!
 

Wood

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It was 39 when I woke up, not a speck of frost in sight thankfully
 

rockm

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Did you spray the night before to limit or in morning after frost already there? I know Wednesday night here will potentially have same issue.
I go to bed before midnight.. Frost typically doesn't appear until just before sunrise--if it does, freezing can also be in the forecast. Spraying at night can help when frost advisories are up, but by the time dawn (ish) rolls around, most of the water you've sprayed has evaporated. Best to get up before dawn and spray then, otherwise, you're probably wasting your time.

BTW, evaporation is a cooling process, so spraying too early might actually make frost more likely as it would lower temps with no promise of warmer temps coming soon (like just before sunrise)
 

penumbra

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We unexpectedly hit 35 last night so I guess I will find out just how low a Brazilian rain tree can go!
Interesting. My BRTs are just about the only trees I still have inside. They are finicky enough under somewhat normal growing conditions. They are not going out for a couple more weeks. Nearly all my other tropicals have been out for two weeks now.
 

WNC Bonsai

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I just set this one out a few days go since there were no projections of temps below 40, then the surprise. Anyway it has now warmed up to about 60 F and the tree looks like normal so maybe this one‘s genes hail from a subtropical or temperate area.
 

rockm

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I just set this one out a few days go since there were no projections of temps below 40, then the surprise. Anyway it has now warmed up to about 60 F and the tree looks like normal so maybe this one‘s genes hail from a subtropical or temperate area.
Last night the frost warning here wasn't posted until around 9 pm.

Sometimes that happens. I expected it without the warning in any case.

The weather in the preceding days was setting this up. We had frost the night before last as well only not as thick. Dry air mass, clear skies, calming winds with temps at 42-37 or so and you get frost. There's no sudden surprise if you watch for it.

This is the time of year that it happens. If you're growing bonsai, you become a lot like a farmer--you develop some intuition about weather. Over time bonsai attunes you to even small changes in weather--like humidity changes and cloud cover, as well as approaching rain. In the last few days, I've gotten a few "memories" posts on Facebook from two to four years ago. Those old posts are about hard freezes in late April and me having to lug all the trees into the basement to avoid it.

April here in the Middle Atlantic states is the worst month for bonsai. It is treacherous with unpredictable weather and trees are at their most vulnerable.

We were 85 degrees only last week. Yesterday it didn't get above 59 with a cold wind and a low of 38 with heavy frost. All my trees are well into leaf and out of storage. If the temp had been forecast to go to 36 or less, I would have moved everything into the basement. If I had tropicals that minimum protection temp would be predictions of nighttime lows of 50-55...
 

penumbra

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A follow up on my earlier post about putting nearly all of my tropicals out. First, I don't believe there is really a thing called luck. I think it is one of those words people use to describe an uncertain chain of events or outcome. We all use the word.
After the night that we spent about an hour at 31 F, with no frost, I scrutinized the tropical I put out and can say I was Lucky. Over 200 plants, about 150 0f which are still in 4 inch pots, but including about 40 larger plants in gallon pots or bonsai pots, with absolutely no damage. This is the only time in the past decade I have not done the plant shuffle. This Luck involved the possibility of cold damage only. I did lose at least a dozen one gallon Japanese Maples that were heeled in pine bark mulch. They leafed out, turned black and died. Best case is root rot, worst case is verticillium wilt.
There you go, good luck + bad luck = no luck. We just focus more on the bad luck.
 

ForrestW

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I just set this one out a few days go since there were no projections of temps below 40, then the surprise. Anyway it has now warmed up to about 60 F and the tree looks like normal so maybe this one‘s genes hail from a subtropical or temperate area.
I left all mine out as well-- it was a little warmer here but I try to move my tropicals in if it is under 40 and that one caught me by surprise.
 

Dav4

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Here in SE MI, we have mid 30's after midnight tonight... with possible snow showers :rolleyes: .

Tomorrow night is a possible freeze with lows in the 20's:(💩:oops::rolleyes:. Methinks all the deciduous trees get moved back into the cold room until Thursday AM. The space under the lights will be tight! 🤷‍♂️
 
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