radiational freezes occur with clear skies at night -- the heat "escapes" up into the atmosphere. when we get frosts during radiational freezes, the frozen vapor falls from the sky onto the plants (kinda like snow, but from a much lower ceiling). they occur usually at dawn. during radiational freezes, there's usually very little wind, but what wind there is is helpful.

advection freezes are freezes that occur because of troughs (pressure differentials, aka wind) -- winds blowing cold air into the peninsula from up north. they therefore have wind chills. advection freezes last a lot longer -- they're like winter storms up north.

it's one thing to keep the frost off of plants, another entirely to keep them above freezing for long periods of time.

sigh. my bananas. my tomatoes. bye bye squash. heck, even my salad crops and strawberries might bite the dust!

floridays, i believe you owe me a coke.

saintpfla...
That depends. First of all, if you are actually in Saint Petersburg, you probably have nothing to worry about. That area won't even hit freezing. The further north and further inland you are, the worse it will be. It also depends on where these plants are situated (N-S-E-W), how much shelter (house/trees) they have, and so forth.

pnbrown...
Here are some definitions I certainly don't take credit for ;)

Advective:
The transfer of a property of the atmosphere, such as heat, cold, or humidity, by the horizontal movement of an air mass. Example: "Today's temperatures were higher due to the advection of warm air into the region."

Radiational Cooling:
The cooling of the Earth's surface. At night, the Earth suffers a net heat loss to space due to terrestrial cooling. This is more pronounced when you have a clear sky.

oh that's funny, we are all encyclopedia sets here, aren't we?

hahahaha :)

Wow what you can learn..lol I didnt know there were different types of freezes..I feel silly

Here in jax they are saying a low of 20 tonight, 29tomarrow night and 31 wednesday... Max and I have been busy dragging things in, re-potting, and today we are headed to lowes to get more lumber for a structure to cover some of my babies. We still have alot of work to do and alot to cover since we are still in the beginning stages of opening a backyard nursery and have tons of cuttings rooting (those come inside).

I hope everyone stays warm and your plants all survive the cold weather setting in. Makes me wander how I ever gardened in ohio..

Happy New Year Everyone!
Donna & Max

ill, one Coke coming up! :)

Dear Floridans: For years, I have noticed that the area around Ocala seems to be subject to particularly low temperatures during cold waves, even though that location is not that far from Orlando, which appears to be much warmer. I just noticed that the NWS is predicting temperatures to fall into the TEENS in the Ocala area on Wed. night. That seems way too cold for most of the plants I usually think of growing in Florida. My question is this: Are there any interesting and obvious differences in plant type distribution in that part fo Florida due to these cold pockets?

Good Golly, Ollie! I've been gardening (mostly in Florida) for a very long time (over 40 years) and I never KNEW about radiation vs advection freezes! This forum is the most interesting thing I've ever belonged to, I swear!! The combined total of knowledge and experience to be found here is utterly amazing! Thanks for that explanation Floridays, Ill-Man, and MusicMan. (Floridays...you a parrothead, by any chance?) I really enjoyed learning about that, and it all makes sense, now that you fellas have explained it so well.

Good luck, everyone! I sure am happy the weather is cooling down, but why is it always feast or famine?? Either ninety degrees or a plant-killing freeze? Just some 40 degree nights and 60 degree days would have made ME happy.

Oh, well...it is what it is! Grab those blankets & lights, cross your fingers, and hope the REAL Ma Nature has a heart!

Marcia

Rockman, that is a fascinating observation.

True, too. I've spent a great deal of time in and around Ocala and the National Forest. Just from basic observation, the area around there reminds me far more of Georgia in terms of plant life. Hardly a trace of anything tropical. Whereas, yes, 50 miles east everything shifts to an entirely different zone.

I'd like to hear from someone who perhaps lives up that way and can give us some greater insight on this. I love microclimates and stuff like that :)

Im in Ocala, and we are always far colder than anyone else, it seems. Ive already had 2 hard hard frosts this year, when no one else has. Its really odd how cold it can get right here. My very tall bananas have already frosted back twice, they are full of brown leaves, with a few new ones coming up. I didnt cut off the old ones, figuring something like this was coming. I have one tomato plant that got frosted back really badly last frost, but it did come back. Today, Im digging that baby up, stuffing it in a pot, and bringing it in. Ill set it back out when the coast is clear, whenever that is. But yes, its true, Ocala seems like the coldest spot in Florida. Especially my yard.

oh criminy! I don't have any spare sheets and the lights are still on the tree! SO - I did put all plants I could lift (and thought could stand the weather the next few nights)against the south face of the house, as close together as I could.(a' la the penguins). Since that area has a 24"high fence, I plan to use the black weed block to wrap the entire area- maybe even two layers, sides and top. I will also water them good within the next hour and hope that will help. Some plants will be covered with staked down paper bags and some of the most tender will be brought into the lanai - with the fan running on low. Some that I can't move will get wrapped if I have time and enough weed block. If anyone has more or better ideas, please post them, as I will be checking back here frequently. cora

MusicMan: Yes, I am downtown St. Pete on my little 1/2 acre of paradise...

I haven't caught the latest weather forecast. Is it true that my area won't get the freeze?

The UF IFAS site says, "Coverings protect more from frost than from extreme cold. Covers that extend to the ground and are not in contact with plant foliage can lessen cold injury by reducing radiant heat loss from the plant and the ground. Foliage in contact with the cover is often injured because of heat transfer from the foliage to the colder cover. Some examples of coverings are cloth sheets, quilts, or black plastic. It is necessary to remove plastic covers during a sunny day or provide ventilation of trapped solar radiation. A light bulb under a cover is a simple method of providing heat to ornamental plants in the landscape."

It's the first sentence that scares me. Frost is associated with radiant cooling. But the cold front on Thursday morning will bring heavy winds with it and "advective" cooling, which will reduce the benefits of coverings. I've always relied on black weed block covers and they have never let me down. But I'm beginning to think I was lulled into a false sense of satisfaction, since in the past ten years all I've seen are major frosts associated with radiant cooling. I'm getting that sinking feeling that, despite all the plant coverings I'll put on Wednesday night, they may be for naught.

Here is a link that might be useful: The UF link -

I just walked the garden to see if theres anything I can save; most everything is too big and is just going to have to tough it. However, in looking at a few milkweed volunteers that I have, I found 2 baby monarchs. I brought them in with some leaves, but Im afraid these nights of hard freeze will kill my milkweed plants and they won't have anything to eat. Is milkweed really tender or does it have a chance to save its leaves thru this hard freeze?

bsewall, thanks so much for the UF link. It seems I was doing something right, afterall. Also, I am in a microclimate of sorts, where the river wraps around three sides of us. I'm almost a mile from the water - and pray that's close enough! I've watered all the plants but must wait until my DIL is home from work to help me move the big plants. cora

saintpfla,

you'll probably be ok. NWS is predicting 31 for downtown on Wednesday night. Check the link below...

Here is a link that might be useful: St. Pete forecast

Hey y'all:

Time for a quasi-dumb question. Would a camping tent work as well as one of those greenhouses? Just a thought.

Julie in WPB

Well, it's almost 3 p.m. here in Sanford and it's still pretty warm outside.

The forecast predicted 37 degrees tonight with a wind chill of 27. I'm going to take a chance and not cover tonight, but tomorrow I'll be doing the bedsheet boogie!

Kathy

Hi, Kathy! Your plan sounds kinda like mine, except Mark & I already moved about 150 potted cuttings and things into the garage. I don't think they were in danger tonight, but we didn't want to have to be moving them tomorrow, after it got cold outside. Then tomorrow, I'll cover a few things, and the rest will have to get tough or die.

I had over 75 coleus started that I was planning to use to refill my beds with in a few weeks, and those were my prime concern, so they are all safe now. Of course, the CARS are now going to be OUTSIDE, but hey, it won't kill them.

Good luck!
Marcia

Thanks for the link and the information MusicMan! :)

manature,

"Either ninety degrees or a plant-killing freeze? Just some 40 degree nights and 60 degree days would have made ME happy"

You couldn't have it better!! Those are my sentiments exactly, I love cooler weather just like everyone else, we deserve it after 7 or 8 months of 80's and 90's, but not freezing temps, that belongs to the northern states, they are used to that, we aren't.

Thanks to everyone that posted all that great info and links, all very helpful. I too didn't know there was an advective and radiational freeze, who knew?? I LOVE THIS FORUM...

Hi Saintpfla,

I've been here all my life...remember when most of the county was orange groves, there were even some avocado groves in Oakhurst close to the water north of Ulmerton. The only frost in Pinellas will be up on the ridge (Ridge Road - 60ft elevation and 5 miles inland) and that's only if temps are predicted to be below 30F. Not sure how others feel about this statement but water MELTS at 32F, it doesn't always FREEZE at 32F, thus my statement about the frost here in our local area based on my observations. Rarely will we get any frost if you're within 2 miles of the water, on either side....

Bummer, the Gators lost :-(

have pulled my three potted bruggies under the patio..the ones in the ground are pathetic, anyway. Wonder if the pods (not yet brown) on the blue pea vine will be okay? The tropical garden may take a hit..not much we can do about that...too big an area. Sometimes we must fall into that 'micro-climate' factor...some things that area supposed to be zone 10 will make it here...easier than trying to grow a zone 8 plant. Also pulled a couple of small hibiscus (in pots) and desert rose. Plumeria?? there are no leaves right now... not sure what to do about those.

Hi Tomncath!

Bummer USF lost too! :-(

So, it sounds like our plants will probably be spared. Whew!

I do remember the loads of groves -- especially down Starky when it turns into Keene and near Bryan Dairy. I don't recall the avacodo groves though, for some reason.

I also remember Christmas season 1989 when I had family visiting from Boston. We had such a cold front come through that it actually SNOWED at St. Pete Beach! I saw it and was like, 'what the heck is THAT?!?...'

I remember the rolling, forced blackouts too and how my heat could not keep the house warm enough! Brrrr!

Sadly, loads of tropical fish and birds perished in the cold too.

Anyone else remember this?

shed becomes refugee camp for tender plants...

i went ahead and dug out my dwarf bananas. they should be ok.

almost peaceful...

bye-bye, bananas!

bye-bye, brugs! thanks for one last bloom.

i should sell tickets to my haunted garden... boo.

i decided to rip out the seminole squash. it has been very productive (i picked four today, ranging from 2.2 lbs to 3.5 lbs).

fried green tomatoes and green tomato pickles...

Oh, yes, I remember the Christmas of '89! My son, DIL and grand daughter drove from Jacksonville down to Largo on Christmas day. It took them a half hour just to get over the Mathewes bridge and a good two hours just to get out of Jax. All the bridges were frozen and it was cold enough that the snow STAYED on the ground. I prefer my white Christmases to be on cards, thank you!! cora

I wrapped my two bananas (one 4' dwarf cavendish and one 5' apple bannana) in sheets, pulling the leaves stright up vertically while wrapping them. Hopefully they'll survive the next two nights.

Here in St Pete weather.com is predicting a low of 37 tomorrow night, but that must be for downtown on the bay. It always seems to get a few degrees colder here at my house which is 3 miles inland. The local news just predicted 29 for a low tomorrow night in Tampa just across the bay. Yipes!

I live in the Ocala National Forest. I am certain my elephant ears that are 15 feet tall are going to perish tomorrow night. Meant to take pics of them today and forgot. I have a ficus tree that is 20 years old and is outside and about 10 feet tall. I have it covered but am worried about the hit it is going to take. Been in the family for a long time. The ficus has not lived outside until I inherited it 4 years ago. This cold spell has me concerned.
Current temp is 57 degrees.

I dug up my newly planted Ice Cream banana and put it in the garage. My young papayas are most likely history...but alas I have seedlings. I've done the best I can do now all I can do (we can do) is pray for the best. Welcome 2008! (I might go out and take some cutting from my brugmansias-hehe)

stay warm, friends!

every time i look at wunderground, the minimum temp tomorrow night gets a degree colder. now, it's 23. i think i'll stop looking...

Nice photos, Ache! The temperature has not dropped much here, but the winds are really kicking up. Had several frost blankets blown off that I needed to secure better. One gust blew over potted Papayas and Moringas on the west side of the house.

In my shower stall are Breadfruits, Cacao, Cashews, Camitos, Canistels, Peep Thong, Picasso's Paintbrush Croton, Calabash Nutmeg and Mamey Sapote.

Here is how "Liberty", my 190 lb Mastiff helped today(G).

Lisa

Gosh, I just heard on WESH weather that the prediction for Tampa tomorrow night (early Thursday am) is 21 degrees and that it will stay low for quite awhile. They are saying it will tie or even break the coldest night on record for Tampa! You guys over there better bundle up yourOWNselves, and forget the plants! You'll have frostbite and chilblains if it really does get that cold! Eeeeek.

Yes, I remember the '89 freeze. It snowed several places and boy was it cold! And one year a bit earlier than that, it snowed when I lived in Tampa. Somewhere, I have pictures of my red hibiscus flowers filled with snow flakes! It didn't lay on the ground that year, but it was definitely snowing.

Ill, your shed looks like my garage right now. We brought about 15 wheelbarrows of potted plants in. Just a few things to cover tomorrow, and that's it. Strictly survival of the fittest from that point on.

Marcia

Thursday...GFS and NAM-WRF models are spitting out some light quantitative precipitation forecast amounts
along the coast as onshore flow becomes better established. At the
same time...850mb temperatures will be -1c to -3c. So if any precipitation falls
from the stratocu Thursday morning it could very well be in the form of
flurries or very light snow showers along the space and Treasure
coasts. No accumulation would be expected. We saw a very similar
situation on Jan 24 2003 when very light snow/flurries were reported
along the Brevard coast.

Well, I spent the better part of this afternoon watering those plants that are in the ground, making sure to not wet the leaves. Then I hauled in all the smaller pots, mostly Salvias, milkweed, Angelonias, herbs, and impatiens onto my porch. My husband brought in all the larger heavier ones including my Cassia bushes, our Staghorn ferns. I didn't cover anything tonight - 37 is the low for our area, but tomorrow I will cover my Black and Blue saliva that is in the ground, my purple firespike and my red one. I am hoping to somehow cover my tender Dutchman Pipevine that grew back this summer. Its on a tall wooden fence that is also on my neighbors side. I always have trouble getting something to stay on it when the wind is blowing. The rest will live if it is meant too. If not, it will give me a reason to redo my beds. But it hurts to think that some of my big Pentas have lived and bloomed continously for about 4 years now!

All our new plants in the front island may not make it - Crotons, some varieties of gingers, hostas, and bromeliads got another layer of mulch around them this weekend. Hope it helps.

Gotta go soak my sore Frozen Shoulders!

Don't forget to run your pool pump tomorrow night if it gets down to the lower 20's!

Thanks for the explanation on types of freezes.

Now that I'm aware of them I realize I see radiative freezing frequently on clear, still dawns here that are right around 30-34 degrees. Very common in December. We call advective freezing "another G-D nor-easter".

My folks are away from home (Ocala forest area) so I'm afraid all my mom's plants are going to be killed, including the little potted key-lime.

Weather underground says it will be 16 degrees here tomorrow night. That's just ridiculous. I object.

All of my tender plants are packed into the greenhouse and I have two electric heaters set up out there (one is a backup) so those plants should do fine. We've already had two frosts here this season, so I don't think the gardens could look worse after this.

I'm going to have to go out first thing Thursday morning and put warm water in the birdbath. Last year when we had a really cold night, I saw some very confused birds skating on the ice in the birdbath the next morning.

Maureen

I'll have to check my birdbath for skating birds too!
How cute!
I remember a few good freezes here too. One with snow falling.
Guess the subtropics aren't immune.
I'll cover a few things tomorrow (that I really like)and wait for everythig else to recover.
There are a few ultra tropical houseplants that I'll bring inside.
Maybe my peach tree will give me some fruit this year!
I quess the papayas will slow down ripening for a while now. That's OK. Had plenty lately.
Unfortunately there's finally a bunch of bananas coming on now. First in years. Hope they don't get frozen out.
We're gonna be close...35 predicted tommorrow night.

Keep warm all.

Although I've never been fortunate enough to see Florida snow, I do remember Christmas '89 and the blackouts. We fired up the Coleman camping stove and made hot chocolate and it was all good, if not a bit chilly. I believe that was the winter when our neighbors' sprinkler system froze and busted open, spraying water all over the sidewalks, which then refroze, making a nifty skating rink for the neighborhood kids (I was one of them... hehe).

I feel like indulging my inner nerd tomorrow night... probably set out some different containers of water to see if I get ice cubes ;)

Im way on the other side of the country (z9b California), but after hearing of the freeze youguys will get tomorrow, i wanted to check out what some of you would protect, since we had a similar freeze this past January. I think some of you are over-reacting. Bananas will be fine- dont even worry about protecting them. Of course, they will be completely defoliated and if they are fruiting, the fruit will be lost, but they rebound in the spring. Of course our freeze and your freeze are definately different, but here is a list of plants that survived down to 18 degrees for two nights. Note that i said "survived". In some cases, they were defoliated.

Australian tree fern
Dwarf black tree fern
All of my citrus (mandarins, tangelos, key limes...) minimal damage to any of these.
Queen palms
Duranta
Brugmansia
bird of paradise (both reginea and nicolai)

If you are staying in the 30s, you will probably only get a light frost. Every December here brings a couple of nights in the low 30s range and the damage is only for the ultra-tropicals. Citrus will not incur damage in the low 30s. Citrus are grown commercially here and they fruit during the winter months. Mine right now are all heavy with their crops. Here are a couple of pictures that i took this week (we've had low to mid 30s all month and a night with 29 right before sunrise.)
{{gwi:65070}}
Majesty palm and small clumps of d. lutescens
{{gwi:984492}}
Mango seedling
{{gwi:984493}}

Thanks, Central Cali for checking in.
That's a nice young mango you've got!
It is a mango, isn't it?
And a pretty garden too.

This will be a quick but cold front coming through here.
I think most everything will survive here too, much may defoliate. But it grows back!
How's everything doing there?

Where are you in central cali?

Tree

yup, thats a mango seedling treefrog, thanks. Im in the smack center of CA in Fresno. I live in the central valley where we get LONG dry summers (typically above 110 degrees) and cool, short, wet winters (Dec and half of Jan). So far, we've had a couple of frosty mornings, but nothing to hard to protect any plants. There is only a bit of damage to dypsis lutescens, majesty palm, hibiscus and bouganvillea. Temperatures begin to rise quickly begining this first week of January so there is minimal danger for any more damage than what is shown in the pics above.

central cali-- making things much worse here is the fact that the weather has been warm (no, HOT) the last weeks. the plants haven't had a chance to harden off, as they have out there in CAL. rose bushes, for instance, aren't bothered usually by low-mid-20s... but mine have a TON of very new growth on them that will surely get nipped. ditto with tomatoes and azaleas and gardenias.

Exactly so, Ill-Man! My plants think it is still summer, with near ninety degree temps all week. They are going to be in for a real shock tomorrow night, and I have no doubt that some things will die back to the ground and look ugly for awhile, and some things will die, period.

Marcia

Marcia! You had me freaking out...21 degrees in Tampa! I watched 4 local weather reports this morning and they are now pedicting anything from 29 to 31 for Tampa. Also, it was warmer last night than they thought it would be (44 to 46).

I think the 21 is with wind chill.

I just spread 10 bags of mulch on some of my plants and could use ALOT more. But it will have to due.
On the bright side my garage smells amazing! I brough most of my potted plants in and my michelia alba is one of them. It has been in full bloom for a while now and the fact that it is in an enclosed area just makes it smell that much more amazing!

Sorry for the fright, Laura...that's what I heard on tv, and I almost fell over when I heard it, too. I'm pretty sure that particular weatherman said that was his prediction for the actual temp, rather than windchill, but I could be wrong. I listened to and read and checked so many sources, my little brain may have absorbed one prediction too many. My capacity is low these days!

Hope you stay warm tonight!

Marcia

gcmastiffs,
Your dog looks a lot like my Champion Muggs McGinnis that I owned back in the 70s-80s. Could it be a decendant??

Well, looks like the predictions have dropped 5-6 degrees for us in Pinellas, we'll for sure have some burned up tropicals but my sisters tangreens will be wonderful after the chill dehydrates them a little. More trivia time - did you live here 01/19/77? We had a friend that went skiing on one of the golf courses during the snow flurries that lasted until mid-afternoon, and we made an 18" tall snowman! I'll see if I can find the pictures.... On a serious note though, good luck to everyone.

Chris went and put a digi thermomenter in the ghost orchid slough we found this summer. It will be interesting to see if any damage is incurred from this.

Tomcath,
1/19/77 is when my youngest brother was born. We always thought it was so cool that it snowed the day he was born. We made a very small snowman- probably only 6 inches tall. But it was such a neat experience because it was my 1st experience with snow!