Yesterday woke up to something no zone pusher wants to see...  Weather report claimed a low of 40f with a real feel at 38f.  I put all my potted palms under the eaves as a precaution but a few things still got brown splotches...

That's ice on the lip of the pot..

on my neighbors lawn...

 

Woah, that looks like you lower than 38F, usually 36F seems to be the crap spot ^TM for when frost forms.  I know it can form at higher temp but from what I have seen over the years 36F with a clear night and no wind equals frost.

I feel you, there have been many cold nights with frost here in the Bay Area lately. I'm paranoid every time I feel how cold it is. I got some spotting on a couple of my palms recently, but nothing too bad.

Good luck with your palms.

34 minutes ago, nachocarl said:

Woah, that looks like you lower than 38F, usually 36F seems to be the crap spot ^TM for when frost forms.  I know it can form at higher temp but from what I have seen over the years 36F with a clear night and no wind equals frost.

I think you may be right.  As soon as I see lows forecast for 37 to 38, I get nervous.  In my yard, due to some local topography, I start to see frost at about 37°f. But sometimes I get all the way down to 32° and manage to dodge the bullet.  Wind and humidity I am sure are big factors.

Yup, even out here this morning. I couldn't believe it!

frost is such an ugly sight!

2 hours ago, OverGrown said:

Yesterday woke up to something no zone pusher wants to see...  Weather report claimed a low of 40f with a real feel at 38f.  I put all my potted palms under the eaves as a precaution but a few things still got brown splotches...

That's ice on the lip of the pot..

on my neighbors lawn...

 

that is a scary sight. did you have any frost on your plants?

17 minutes ago, Josh-O said:

that is a scary sight. did you have any frost on your plants?

No frost on the plants but there has been progressive browning over the last couple days of cold nights.. 

Today it was light misty rain, now it is predicted to drop below 32f when the cloud cover moves away.  I started drying out my palm covers from the wet, tonight heard the cold forecast again.  I can handle it, at least it is not down below 25f, just busy, putting some things back out after the 11pm news. 

Call that the Gloom of Doom™ for your Latania palms. 

Gloom of Doom ^TM and Crap Spot ^TM for sure.  Last night we had a breeze that started sometime...... after midnight ♪♬♪♫ ......and brought the temp up 3 degrees.  I bottomed out at 38F but was back up to 41F by 7 AM which is usually where I bottom out.  Looking on the wundermap it looks like the wind sheltered spots stayed pretty cold.

Edited December 31, 201510 yr by nachocarl

Help me understand something here - We don't get a hard frost like this until 28 degrees or thereabouts. Is this some kind of California paradox where frost occurs above freezing ? 

Edited December 31, 201510 yr by santoury

Santoury,

I regularly (or used to since our climate has warmed a bit) see frost here in Central FL with temps in the mid - upper 30s and calm winds.  I saw this regularly in the winter months here as a kid in the 90s.  You have a point, when I lived in Northern VA, I saw many nights/mornings which featured frost, but it was (from what I remember) always 15-30F when I noticed seeing the heavy frost. 

It has been a good 5 years or so since I have seen significant frost here in Orlando.  Notable events I can remember include seeing frost forming on the grass at 7pm on the night of January 24, 2003 after a day with a high in the low 40s (Maitland).  Also, I saw frost forming on grassy areas many evenings in January and February 2010, when I lived in Altamonte Springs, a NW suburb of Orlando.  I remember taking walks each night and feeling like I had moved to Atlanta or something early that year.  I enjoy walking in the cold.

There was a great thread done many years ago on this forum about frost and how it can form at higher than freezing temps.  I took a look in the archive and couldn't find it and I can't remember what the heading was.  I think the thread had it's origins in "Specter's Garden" or "Specter's Jungle" and made its way over to here.  It is about radiant heat loss where on a calm and clear night an inversion occurs with heat rising causing cool air to be pushed down and temps at the surface to drop below freezing. 

 

 

Very interesting- I'd love to read that if somebody can dig it up somewhere. 

 

Whoa, Peter, that's scary; we're neighbors, practically.

So far, no frost for me, as the Frost Nazi might say, which makes me super curious.

Need to do a bit of research on frost.

1 hour ago, DoomsDave said:

Whoa, Peter, that's scary; we're neighbors, practically.

So far, no frost for me, as the Frost Nazi might say, which makes me super curious.

Need to do a bit of research on frost.

I wouldn't think you would get frost in your jungle because you have so many canopy trees. maybe in your open exposed area where you cut down the pepermonster? 

2 hours ago, Josh-O said:

I wouldn't think you would get frost in your jungle because you have so many canopy trees. maybe in your open exposed area where you cut down the pepermonster? 

I thought about that, too. I looked, and:

"No Frost for You!"

So says the Frost Nazi^TM, so far. Including this morning. This is that time when it gets a bit nerve-wracking.

We are in the teeth of the frost season. More frost danger still lies ahead if it doesn't rain, especially if we get a nasty Stan Anal, which blows our precious cloud cover away.

Hopefully, I will continue to offend the Frost Nazi and it will be no frost for me. (Raising middle finger skyward, then placing thumbs on ears and waggling fingers in the same general direction.)

If it does freeze, it will be interesting to see how much of a difference my Orgiastic Archie Forest will make. They'll likely protect whatever's beneath them, though it's had to say how the tuckeri themselves will fare.

6 hours ago, nachocarl said:

There was a great thread done many years ago on this forum about frost and how it can form at higher than freezing temps.  I took a look in the archive and couldn't find it and I can't remember what the heading was.  I think the thread had it's origins in "Specter's Garden" or "Specter's Jungle" and made its way over to here.  It is about radiant heat loss where on a calm and clear night an inversion occurs with heat rising causing cool air to be pushed down and temps at the surface to drop below freezing. 

 

 

I remember that thread too.  A very good one.  I bet Moose could find it!

where is moose? I'm surprised he hasn't chimed in yet?

1 hour ago, DoomsDave said:

I thought about that, too. I looked, and:

"No Frost for You!"

So says the Frost Nazi^TM, so far. Including this morning. This is that time when it gets a bit nerve-wracking.

We are in the teeth of the frost season. More frost danger still lies ahead if it doesn't rain, especially if we get a nasty Stan Anal, which blows our precious cloud cover away.

Hopefully, I will continue to offend the Frost Nazi and it will be no frost for me. (Raising middle finger skyward, then placing thumbs on ears and waggling fingers in the same general direction.)

If it does freeze, it will be interesting to see how much of a difference my Orgiastic Archie Forest will make. They'll likely protect whatever's beneath them, though it's had to say how the tuckeri themselves will fare.

have you even got down to 32 yet at the "Death camp"?

So far my lowest temp at my carlsbad garden was 38 for only on night and the next lowest was 40 this year.

The Vista garden is another story

24 minutes ago, Josh-O said:

have you even got down to 32 yet at the "Death camp"?

So far my lowest temp at my carlsbad garden was 38 for only on night and the next lowest was 40 this year.

The Vista garden is another story

Don't know for certain - misplaced my hi-low thermometers -- but no obvious signs of freeze. Bougainvilleas and baby ravenalas are canaries in the coal mine, and so far no sign of trouble at all.

1 hour ago, DoomsDave said:

Don't know for certain - misplaced my hi-low thermometers -- but no obvious signs of freeze. Bougainvilleas and baby ravenalas are canaries in the coal mine, and so far no sign of trouble at all.

perfect

Way back in ancient times, when I lived in San Bernardino, my place was in a "cold pocket" and it

got

cold

and

I mean

COLD!

Like maybe mid-20s F, so the pipes froze, and you couldn't wash your filthy carcass with a shower in the morning. Had to resort to that old trick of leaving a drippy-drip of water on at night.

All the bougainvillea froze. All of the Euc. citriodora froze.

Even the garden hose froze.

And the top of the car, like Peter shows.

I doubt he got that cold, but still, scary, a shock.

My closest weather underground station said 36 this morning and there was frost again, but the palms didn't appear to have any on them. Ugh. Tonight should be a tad warmer. Happy new year!

8 minutes ago, Matt in OC said:

My closest weather underground station said 36 this morning and there was frost again, but the palms didn't appear to have any on them. Ugh. Tonight should be a tad warmer. Happy new year!

happy new year!

19 hours ago, nachocarl said:

There was a great thread done many years ago on this forum about frost and how it can form at higher than freezing temps.  I took a look in the archive and couldn't find it and I can't remember what the heading was.  I think the thread had it's origins in "Specter's Garden" or "Specter's Jungle" and made its way over to here.  It is about radiant heat loss where on a calm and clear night an inversion occurs with heat rising causing cool air to be pushed down and temps at the surface to drop below freezing. 

19 hours ago, santoury said:

Very interesting- I'd love to read that if somebody can dig it up somewhere. 

 

 

Heat moving around is called thermodynamics. Heat can move around in three ways. Heat is the kinetic energy (motion) of atoms/molecules. At absolute zero all motion stops.

Convection Is when the molecules move around through fluid flow (like the wind blowing) and is what is called an advective freeze. The fluid air flows and moves the heat from one place to another.

Conduction of heat occurs when molecules/atoms touch one another and transfer heat energy by the transfer of motion, like billiard balls colliding. If you go outside on a cold morning and touch the cold handle of your car door, heat will be transferred from your hand to the door handle. Heat will be transferred from your plants to the air from conduction.

Radiational heat transfer occurs through the electromagnetic spectrum primarily in the infrared.. That is why it feels warm in the sun. Heat will be transferred from one body to next through radiation if one bodies temperature is lower than the other.

On calm and clear nights frost occurs when surfaces radiate their heat to the sky which acts like a black body, an absorber of radiation. Surfaces lose heat to the sky through radiation. If the wind is calm, the air will not conduct heat to a surface as fast as it's heat is radiated away to the sky. This causes surfaces to be colder than the surrounding air and frost can form even if the air is warmer than 32F. The surface is 32F or colder or frost would not form. The rate of heat transfer through conduction is a function of the temperature differential between objects. At about 38 or so depending on the exact conditions, heat is conducted fast enough from the air to a surface to keep the surface temperature above freezing.

Ed in Houston

 

 

 

 

 

 

Overgrown, that is scary frost at your place. Here, most people think of Los Angeles as being summer-like all winter long. I guess not --- or perhaps you are east of the mountains where it gets colder in the desert?

Thank you Ed - fascinating! 

HAPPY NEW YEAR everyone! 

1 hour ago, Ed in Houston said:

Heat moving around is called thermodynamics. Heat can move around in three ways. Heat is the kinetic energy (motion) of atoms/molecules. At absolute zero all motion stops.

Convection Is when the molecules move around through fluid flow (like the wind blowing) and is what is called an advective freeze. The fluid air flows and moves the heat from one place to another.

Conduction of heat occurs when molecules/atoms touch one another and transfer heat energy by the transfer of motion, like billiard balls colliding. If you go outside on a cold morning and touch the cold handle of your car door, heat will be transferred from your hand to the door handle. Heat will be transferred from your plants to the air from conduction.

Radiational heat transfer occurs through the electromagnetic spectrum primarily in the infrared.. That is why it feels warm in the sun. Heat will be transferred from one body to next through radiation if one bodies temperature is lower than the other.

On calm and clear nights frost occurs when surfaces radiate their heat to the sky which acts like a black body, an absorber of radiation. Surfaces lose heat to the sky through radiation. If the wind is calm, the air will not conduct heat to a surface as fast as it's heat is radiated away to the sky. This causes surfaces to be colder than the surrounding air and frost can form even if the air is warmer than 32F. The surface is 32F or colder or frost would not form. The rate of heat transfer through conduction is a function of the temperature differential between objects. At about 38 or so depending on the exact conditions, heat is conducted fast enough from the air to a surface to keep the surface temperature above freezing.

Ed in Houston

 

 

 

 

 

 

Very good explanation! And happy new year!

Edited January 1, 201610 yr by Monòver

Happy New Year everyone.  No frost yet in Corpus Christi, but it has happened a couple of times just north of Corpus.

More frost here, down to 35 this morning. Apparently I live in the coldest pocket of west Orange County! Happy new year!

I got down to 36 briefly last night, but 38 was my low this morning.  Lots of 20s in the Bay Area so I am happy!

Matt,

I feel for you.  I think I live in a cold pocket in Flour Bluff, here on the east side of Corpus Christi.  My yard some nights is almost as cold as the airport, which is about 20 miles inland from the Gulf, yet I am only about 5 or 6 miles inland from the Gulf and only .6 of a mile inland from the Laguna Madre.  If it makes you feel any better, even though we have had a very mild winter so far for South Texas, we are having a chilly raw damp day today, with highs today and tomorrow only about 45F to 50F, when our normal high is 67F.

My "Up and coming Vista garden" hit 38.7 I dodged a bullet their. That garden in defiantly in a cold sink.  The saving grace is that it has very good air drainage, 405' in elevation and south facing. Still stressful to say the least

My carlsbad garden has been in the low to mid 40's all year for the low. never a stressful night here  

Burn is showing on a few of my newly planted palms...I will post pictures when the wind calms down around here.

To battle the frost, I rigged up a homemade contraption.   It consists of cardboard and shade cloth to provide "canopy" from airflow down the hill that abuts the garden. 

In addition I filled a large tub of water and added two fish tank heaters.  The theory being just enough heat and humidity would be trapped under my make shift canopy.

I also added a fan to circulate air too.  Not sure which component worked best, but since adding these precautions to this corner of the yard, I have had no frost on palms and other tender plants in the area.

Have had frost on the lawn as previously happened.  So, my "duct tape and bailing wire" solution seems to have worked.

4 hours ago, Hammer said:

To battle the frost, I rigged up a homemade contraption.   It consists of cardboard and shade cloth to provide "canopy" from airflow down the hill that abuts the garden. 

In addition I filled a large tub of water and added two fish tank heaters.  The theory being just enough heat and humidity would be trapped under my make shift canopy.

I also added a fan to circulate air too.  Not sure which component worked best, but since adding these precautions to this corner of the yard, I have had no frost on palms and other tender plants in the area.

Have had frost on the lawn as previously happened.  So, my "duct tape and bailing wire" solution seems to have worked.

I think the fan has been the saving grace in this situation. Frost wont form on the fronds if there is sufficient air movement. That's why citrus farmers have frost fans in the fields in the central valley for this very reason. In most cases a fan can actually warm things up a bit as well as keeping the frost from forming. 

your ficus D. looks real nice BTY!

I'm looking for one. Any idea where I can pick one up?