winter cold event vs 9b/10a palms

[sonoranfans]

this past winter we got hit with a 29-30F advective cold event with frost.  Initially all leaves were burned on Royals, archontopnhoenix(myolensis, alexandre, maxima), Kentiopsis O, dypsis pembana, lutecens. and a surprisingly large amount of damage(40%) on a big caryota mitis right next to the house.  These palms are all coming back, no spears were lost and ~3 new leaves have opened on all the crownshafted palms.  This  cold even happened a couple weeks after I removed 2 live oaks and radically cut the canopy back on 4 others, leaving all of these under an open sky.  Yeah, I could have left those oaks in, and the damage would have been ,a fraction of what happened but those oaks were crowing these palms so I cut them out/back.  Here are pics from a drone above the house. First see the royal, caryota mitis, kentiopsis, dypsis pembana after new growth.

[sonoranfans]

Second, another royal recovering with the top green leaves being opened after the warm up.

[sonoranfans]

Finally it should be noted that all these palms are recovering nicely with the achrontophoenix growing out the fastest after defoliation.  the other interesting observation is Beccariophoenix alfredii(I have 3) not even touched at all after the freeze/frost.  Afrer opening up the canopy these alfredii are responding very nicely to the increased sunlight(.  I like all of these palms but the surprise is how much better the BA was than caryota mitis and (less of a surprise) the crownshafts.  The Alfredii are looking like a great palm for the tampa area.

[kinzyjr]

Nice pictures!  The damage this year was a lot more than my 28F would have normally done.  Seems like this was the year of the fungal infection as I lost an archontophoenix alexandrae to a secondary fungal infection after the cold, and now that my bismarckia nobilis has put out a few new fronds, I can see spots that were damaged on the new fronds that couldn't have possibly been exposed to the air.  The palm was just strong enough to shrug it off and keep growing.

[Sandy Loam]

Wow, that is good news about the recoveries (and the beccariophoenix alfredii being so impervious to cold), but I agree with Kinzyjr:   The aftermath from this January's freeze was worse than it should have been for those temperatures.  This really goes to show how a quick 28 degrees (or, in your case 29-30 degrees) is harmless, whereas a prolonged freeze is damaging, even if your palms spend the daytime hours above freezing.  Four days in a row didn't help either, followed by another two day freeze a week and half later.  A quick one-night freeze (at the very same temperature, or even a few degrees colder) would have produced a different result for your palms.

 

Nevertheless, your news is all good.  I lost some of my palms at 23.4-24.5 degrees, but I am farther north than you.   Our typical freezes tend to be quick, painless, don't start until the middle of the night, and are over by dawn.  This past January was different and I hope we don't have another one like it for a while.

[sonoranfans]

Good point about the duration of cold sandy.  I had one night below freezing and a few just above, I was lucky.  The damage seen around my area on larger royals is very similar to 28F, 30F in december 2010.  But taht cold was a radiative event so 20' above ground was warmer than at 3'.  In advective events like this one, the temps near the ground and up at 20 would be close and canopy is not as helpful in an advective event.  The alfredii was defoliated as a small 2' seedling in 2010 frost cold  event, as an older palm it wasnt even touched whike royals burned very similarly.

 

[Phoenikakias]

Palm fronds grown in shade are large, deeply green but,  alas, imo considerably more sensitive to cold and wind. Even after the removal of overhead canopy such fronds never harden off really, they need to be replaced by new leaves. 

[sonoranfans]

Constantantinos the canopy was to the south so most of these palms got 8 hrs direct summer sun each day.   Perhaps only 4 got less than 6 hrs of direct sun each day from april through october.  Of course the royals are about 35' and had no canopy overhead.  SO I would not characterize them as "shade palms" but there was enough overhead canopy on some of them to trap heat against the house.   Of all the palms mentioned, the archrontophoenix species, dypsis lutecens and two of my alfredii saw less than 8 hrs of sun in summer as the sun moves to the northern hemisphere.  the full sun in summer palms(8hrs or more) were 2 royals, the caryota mitis, 3 kentiopsis, one(of three) alfredii, and one(of two) dypsis pembana.  All of those in full sun burned except the alfredii.  One alfredii has been in full sun since it was a seedling, (no overhead at all).  If I just look at the full sun palms, all burned except the alfredii.  that same alfredii was defoliated as a 2' seedling in 2010 frost.  It appears that it has outgrown its frost sensitivity.

[Phoenikakias]

One night below freezing with a min of 30-29 F (meaning that some hours temperature had been just below freezing) does explain alone the extent of the damage. I say it based on local experience in my neck of the woods. Either palms are also exposed to northerly wind or they had been just caught up "with the pants down" meaning they were in active growth condition, when cold spell broke out. This is my humble opinion. 

[kinzyjr]

15 minutes ago, Phoenikakias said:

One night below freezing with a min of 30-29 F (meaning that some hours temperature had been just below freezing) does explain alone the extent of the damage. I say it based on local experience in my neck of the woods. Either palms are also exposed to northerly wind or they had been just caught up "with the pants down" meaning they were in active growth condition, when cold spell broke out. This is my humble opinion. 

This was a particularly windy advective freeze.

[sonoranfans]

this was a frost and a windy advective freeze that persisted for 6-7 hours.  In these types of freezes the temperature at 3' above ground level and at 30' were about the same.  In 2010 we had 28 F, 29F on two consecutive nights but it was clear that height above the ground was warmer and freezing temps only lasted 3-4 hrs or so.  Heat transfer is the real issue since its the temperature of the foliage at each height that really causes damage, not air temperature.  Also my yard was pretty much bare in 2010, many of these palms hadn't even been planted yet.  I planted the kentiopsis and the two royals after that freeze as larger 12-20' palms.  Being near the house can be an advantage if the wind is low and that was the case in 2010 but not this year.  In addition this was a few months after hurricane IRMA blew in and ripped off/damaged 3-4 older but still green leaves.  I'm sure the palms were weakened by the premature loss of all that green matter and the less dense crowns that resulted were not as resistant to the cold.  As far as shade, like I said those palms where the partial southern overhead was removed did no better or worse than others of the same species out in the open in the side yards.  I grew palms in a few mid 20's radiational events in arizona, advective events are significantly more damaging at the same temperature in my experience.  

[Walt]

Well, out here in deep inland, I didn't get hit with an advective event, at least not to my knowledge. The official low recorded at the Sebring (actually in the boondocks many miles S.E. of Sebring) FAWN site was 32 degrees even. I think this was in February. There was one other night in January where the low was 32.? degrees. I don't believe any of my palms got damaged until the 32 degree morning in February. But that being said, I always run several degrees colder than the Sebring FAWN site, as that site is on higher ground than my place. Also, Lake Placid Elementary School has a STEM weather tower tied in to Weatherunderground, and their low for the winter was just over 35 degrees. This is on high ground where it is always warmer on radiational cooling nights. I normally run 7-8 degrees colder than up in town on these nights. Hence, I believe my low was around 28 degrees.

My coconut palm eventually was defoliated except for the very uppermost fronds. My Syagrus schizophylla just feet away was mostly fried, as well as a small (3 feet of trunk) Roystonea borinquena. Also, my Dypsis leptochelios and Adonida in front of my house were mostly fried. But what was odd, my A. alexandrae palm in the same proximity wasn't hurt. Neither was a 10 feet high Brazilian red cloak shrub in the same proximity.  None of my FIcus trees were hurt, and 28 degrees with frost almost always show some leaf damage.

I just found that some palms and plants I would have though would be frost/cold damage weren't. Others were. My jackfruit tree was mostly defoliated, and also incurred wood damage. My big royal palm in my field area was damaged.  But I have an adonida and Vietchia joannis growing under tree canopy, and they were not hurt at all -- once again proving the value of overhead canopy.

Below is my coconut palm regrowing a new crown. You can see the still burned (and I cut off lots of fronds already) fronds on the S. schizophylla and R. borinqena to the left. The other photo shows my Dypsis leptocheilos (with only three new fronds, a fourth that should be opening tomorrow), with the untouched A. alexandrae palm behind it. No doubt the A. alexandrae palm is more leaf hardy to frost than the D. leptocheilos is

[kinzyjr]

@Walt What a difference a few hours south can make!  Up here, we had a pretty solid dose of wind during the January freeze.  It blew all night ~15mph during the coldest night (28F).  February here was easy by comparison.  I've had lower temperatures, but never had damage on philodendrons and sea grapes until this year.  I lost an archontophoenix alexandrae to a fungal infection after the freeze.  The eastern 2/3 of my property is shielded from the north wind by podocarpus hedges12-15ft. high, but how much worse the damage would have been without the hedges is debatable.  The one factor that I can come up with as to why is Hurricane Irma.  I had to trim away some of my canopy before the hurricane and trim some of the sea grape branches away from the house.

Me experience was definitely more in line with @sonoranfans except that I stayed below 32F for more like 8-10 hours.

[Walt]

Well, I  went back into some of the FAWN (Florida Automated Weather Network) January archives, and it appears I was wrong, and that those cold nights were advective, not radiational. For some reason I just didn't recall much wind. But that help explains why some palms got burned and some didn't, and why my big ficus trees weren't frost damaged, probably because there was no frost. My big Ficuas altissima variegata serves as a barometer plant for me. I know from past experience, when the temperature drops below 30 degrees with frost, my tree starts to get leaf damage. It usually is from ground level up, stratified, leaf damage getting less and less the higher off the ground. I've seen times when there was leaf damage up to maybe the 10 feet level, then the damage stops. But with wind, there wouldn't be frost, so the leaves can take down to 30 or maybe a few degrees lower, and not get damage. It's the frost more than the temperature. 

I recall back in January of 2004 I had a low of 29 degrees from an advective cold, and virtually nothing was hurt, only the upper most tip of a new traveler palm frond. But the same 29 with frost would cause far more damage.

In any event, below are some temperature and wind stats from early January 2018 from the Sebring FAWN, Lake Alfred FAWN, and Avalon FAWN (west of Orlando). Again, my place, even though about 8 miles south of the Sebring FAWN, runs several degrees colder. So, again, I believe it dropped into the high 20s at my place. Perhaps not, and my palms just got desiccated wind damage. My Brazilian red cloak shrub is vulnerable to frost, and this shrub wasn't hurt, that's what really threw me off about the cold. So I guess there was enough wind to prevent frost formation on the leaves.

 

[Walt]

I took this photo today in better sunlight. My Dypsis leptochelios was fried. It's opening a new frond, the fourth one since the freeze. But my A. alexandrae palm behind it wasn't hurt from the cold. I thought both species of palms had about the same cold/frost hardiness, but I guess the proof is in the pudding, and the A. alexandrae is more cold/frost hardy.

[RedRabbit]

11 minutes ago, Walt said:

I took this photo today in better sunlight. My Dypsis leptochelios was fried. It's opening a new frond, the fourth one since the freeze. But my A. alexandrae palm behind it wasn't hurt from the cold. I thought both species of palms had about the same cold/frost hardiness, but I guess the proof is in the pudding, and the A. alexandrae is more cold/frost hardy.

A. alexandrae's foliage might be more hardy, but I'm not so sure the plant as a whole is. I think the D. leptochelios has a better shot of coming back from being defoliated. 

[sonoranfans]

My alexandre triple was around in 2010 as a 4-5' overall triple.  they saw 28 plus frost and every single leaf that was outside the(70% coverage) overhead netting was totally fried, just burned.  But under the frost net almost everything was alive.  Looks like you got the better end of the cold this year Walt.  My "canaries in the coal mine" are large royals all around the area, more burn this year, but higher minimum temp(29-30) vs 2010(28, a radiational event).   The wind in my area was a very steady Northerly 6-8mph if I recall correctly, plenty to mute radiational heating from the ground as a a controlling heat source.

[Walt]

2010 had two bad months of cold. First was January of 2010, then again 11 months later in December of 2010. I have lots of damage photos from each long-term (relatively speaking) freeze events. December of 2010 had 11 straight nights (for me) below 40 degrees, six of those nights below 30 degrees. One of those days it never got out of the 30s. That was a first for me, to never get above 40 degrees for a daytime high.

All of the cold tender palms near my house (where I have electric) I protected using heathing cables, string lights, and insulative wraps. No doubt I would have lost some of these palms had I not protected them. Other palms much farther from the house (and in the open) that couldn't be protected where severely damaged (foliage). But many, if not most palms planted back in my more wooded area, where there was little if any frost, fared very well, even when my open yard temperature dropped to an all-time low of 20.7 degrees by the house, but 19.8 degrees farther out from the house. When I take photos I always leave the date stamp on them so I know when they were taken. See photos for yourself.  

[Walt]

I wrapped heating cables, then insulative wraps around the trunks and meristem of my D. leptochelios, A. alexandrae, and Cocos nucifera. While the fronds were totally killed, the trunks and meristem were unhurt. I'm all but sure, that after six nights below 30 degrees, had I not protected them they would have been killed.

[Walt]

Note the totally wrapped palm in the background in the second to above photo above. That is my Syagrus schizophylla palm. I strung a heating cable through the canopy, then wrapped it with heavy quilted mattress covers. Below is a photo after I uncovered my S. schizphylla after 11 nights of pure hell freezing and frost.

[Walt]

Two photos showing how almost any super tender palm can be protected almost 100% from nighttime lows with frost down into the low 20s. I bundled the fronds of my Adonidia palm (at corner of my house), wrapped the trunk and up around the bundled fronds with heating cables, then wrapped quilted mattress covers over everything, basically mummifying the palm. The results after 11 days of nighttime temperatures (with frost) in the 30s and low 20s speak for themselves. However, those days of going all out protecting palms are over for me. BTW, the ixora shrub to the right of the Adonida was covered with many layers of insulative coverings -- as shown in photos.

[kinzyjr]

@Walt My protocol for protection is pretty similar, but on a much smaller scale since my palms are younger.  Can't complain about the results.

[sandgroper]

15 hours ago, Walt said:

Two photos showing how almost any super tender palm can be protected almost 100% from nighttime lows with frost down into the low 20s. I bundled the fronds of my Adonidia palm (at corner of my house), wrapped the trunk and up around the bundled fronds with heating cables, then wrapped quilted mattress covers over everything, basically mummifying the palm. The results after 11 days of nighttime temperatures (with frost) in the 30s and low 20s speak for themselves. However, those days of going all out protecting palms are over for me. BTW, the ixora shrub to the right of the Adonida was covered with many layers of insulative coverings -- as shown in photos.

Do you leave the palms wrapped like that for 11 days straight or do you unwrap them during the day?

Edited June 28, 2018 by sandgroper

[Walt]

6 hours ago, sandgroper said:

Do you leave the palms wrapped like that for 11 days straight or do you unwrap them during the day?

Unless it calls for rain I leave the wraps on (it normally doesn't rain once the cold front has moved in and is in place). It never rained over that 11-day cold period. The wraps would be useless and detrimental if they were soaking wet.

That being said, sometimes the wraps can get somewhat wet from dew formation in the early part of the night. I've found that further covering the cotton wraps with a PVC tarp will keep dew from wetting the cotton wraps. But even without the PVC tarps, for the most part, because the wraps are thick (I try to overlap so that multiple layers are created, which only increased the R value of the insulation) the wraps still function well. The proof is in the pudding (the above two photos).

However, if I had a short palm where I didn't have to get on ladder to remove the wraps, I would remove them during the day, then reinstall them near sundown.

 

[Walt]

To protect small palms and tropical plants, I used to make crude tents, just by driving some metal stakes in the ground around the plant, then place a PVC tarp over the plants, being supported by the stakes. If the stakes aren't tall enough, extend the stakes with 1" PVC pipe or 3/4" furring strips, etc., using duct tape to secure them together (like I said, just crude, but functional and effective).  Also, if before you cover the stakes and plant with a PVC tarp, you first cover the stakes and plant with a blanket (or other suitable insulative material) that will help capture more rising ground heat inside the tent. This tent, along with rising ground heat will keep the inside of the tent 3-5 degrees warmer, but moreover, will definitely help keep frost from forming on the palm's/plant's foliage.

But for more insurance, I use a heat source inside the tent so as to make sure no cold or frost damage can occur to the palms/plants. I have five teflon coated electric skillets my wife has thrown out over the years. The teflon coating is partially gone (why she threw them out) but they still heat fine. I just place a skillet inside the tent and only put it on it's lowest setting. It provides all the heat needed to keep the inside of the tent well above freezing.

Note in the first photo below the blue tent. This is an old car cover I had. I just draped it over the green metal stakes. As you can see in the second photo, the clusia shrub and Ti plant are unscathed!  Note the electric skillet. I would remove the car cover during the day, as it was so easy to do, so the plants could get sun. It  only took seconds to reinstall the car cover at night.

[Walt]

Below is another photo showing a small Howea forsteriana palm that I bundled and covered, and using supplemental heat. I bundled the fronds together, then placed a 5 feet step ladder over it to support the insulative covering.

[Walt]

Below is a photo of my coconut palm when I started installing my protection, as the forecast predicted we were in for more than a week of cold, cold weather. This was December 5, 2010. I think the cold started on December 7, 2010. It was the earliest freeze in my more than 20 years living here. Normally, my first frost or freeze isn't until very late December or early January. 

Note the spirally wrapped heating cable around the coconut palm trunk, and up past the meristem. Also, note the remote thermometer sensor I placed near the meristem area.  I then wrapped over the cables and trunk with either heavy mover's quilts or old quilted mattress covers (work great for insulation). According to my Oregon Scientific base thermometer and remote transmitter, the temperature under the insulation never dropped below 55 degrees! And that is how I've kept my coconut palm from being killed when the temperature dropped to 20 degrees! The fronds can be killed, but the trunk and meristem never experience cold trauma. The trunk and root system have enough starch/food to regenerate a new frond in spring, and then the new frond can start synthesizing sunlight into food. By the beginning of the next winter, the palm as regrown a respectable (although not totally full) canopy of fronds again.

[Walt]

For my cold protection for palm trunks, I found EasyHeat heating cables work better than string lights. The cables are very supple and flexible, and you get consistant heating all along the cables, unlike string lights. My cables are rated at 7 watts per linear foot. They run warm, not hot, to the touch. However, their warmness seems to very, and at times can get noticeably warm. I found that if the cables stay in contact with foliage and even petioles, they can eventually scorch the foliage/petioles. This also applies to palms with crownshafts.

To prevent scorching, I first wrap the crownshaft with a terrycloth towel, then install the cable over it (as shown in below photo). Also, if I must weave the cables around and through the base of the petioles (above the meristem), I place rags or pieces of towels over the petioles so the cables don't directly make contact. I found, for the most part, the heating cables can make direct contact to the palm's trunk, and doesn't hurt it. But again, not so for tender foliage and crownshafts. Note in second photo below the scorched petioles on my coconut palm. This was due because I didn't place a piece of insulative material (towel, rag, etc.) where the heating cable contacted the petiole. It really didn't make much of a difference, because the fronds were killed anyway by the freeze, but it would make a difference if say you could cover the fronds (like cinch them up into a tighter bundle, then wrap over them with insulative materials), when the entire canopy would be protected and not expected to be cold damaged.

[sandgroper]

Thank you for such a comprehensive reply, I really appreciate you taking the time to write it out. I was surprised that the palms could be without sunlight for eleven days, I thought that would have damaged them. Our climate here in Perth never gets down to those temperatures so I haven't gone to these efforts but I have covered my coconut with a cheap plastic greenhouse when it was small.  It is now too big to cover so I have put up some polycarbonate sheeting around the palm to offer some protection frim the cold but it is open to the elements at the top. Thanks again for the very comprehensive answer to my question, cheers!

[Walt]

5 hours ago, sandgroper said:

Thank you for such a comprehensive reply, I really appreciate you taking the time to write it out. I was surprised that the palms could be without sunlight for eleven days, I thought that would have damaged them. Our climate here in Perth never gets down to those temperatures so I haven't gone to these efforts but I have covered my coconut with a cheap plastic greenhouse when it was small.  It is now too big to cover so I have put up some polycarbonate sheeting around the palm to offer some protection frim the cold but it is open to the elements at the top. Thanks again for the very comprehensive answer to my question, cheers!

You are welcome. I once read somewhere (can't recall now) that palm can be covered (blocked from sunlight) for an extended period of time, say 30 days, or more, without any adverse effect. I can't recall, though, what the reason was for wrapping the palm in the first place. It may have been palm hobbyists that were trying to grow palms far outside their cold hardiness range, and would then cover them for a long period during the winter months.

Yes, once a palm gets too big, it's not practical, if not practicable, to protect the frond crown. Being in the northern hemisphere, my cold air normally comes out of the northwest. I rarely have a advective (windy) cold event that damages foiliage on my palms. 95% (if not more) of the time my palm foliage is damaged from a radiational (no wind and clear sky) event. If it's windy, there's virtually nothing you can do to protect a palm canopy on a larger palm.

But what I've tried to do in the past, with some success, is to install a PVC tarp wall 360 degrees around a palm or plant (I have photos somewhere, and if I can find them I will post them). Then, I direct a forced air propane or kerosene heater into the tarp area. Even though the tarp wall may not be as tall as the palm, the heat, naturally rising, helps protect the foliage and keeps frost from forming. But, as you can imagine, is a laborious installation, and costly too, if you run a heater all night long.

But over the years I had to give up on trying to protect the entire palm(s), and now only protect the trunk and meristem. Fortunately, I don't have to do this every winter. It's been about six years since I've had to protect my palms' trunks and meristems. 

BTW, I'm on well water, which is relatively warm (24C). I generally will saturate the soil around my coconut palm so that more heat can be released from the soil at night and rise up into the palm's canopy (on radiational cooling nights). And I've also got up 2-3 times at night and applied more warm well water to the soil (my soil is basically sand) so to add heat to the area around my palm (coconut). 

[mdsonofthesouth]

On 6/28/2018, 8:13:50, Walt said:

To protect small palms and tropical plants, I used to make crude tents, just by driving some metal stakes in the ground around the plant, then place a PVC tarp over the plants, being supported by the stakes. If the stakes aren't tall enough, extend the stakes with 1" PVC pipe or 3/4" furring strips, etc., using duct tape to secure them together (like I said, just crude, but functional and effective).  Also, if before you cover the stakes and plant with a PVC tarp, you first cover the stakes and plant with a blanket (or other suitable insulative material) that will help capture more rising ground heat inside the tent. This tent, along with rising ground heat will keep the inside of the tent 3-5 degrees warmer, but moreover, will definitely help keep frost from forming on the palm's/plant's foliage.

But for more insurance, I use a heat source inside the tent so as to make sure no cold or frost damage can occur to the palms/plants. I have five teflon coated electric skillets my wife has thrown out over the years. The teflon coating is partially gone (why she threw them out) but they still heat fine. I just place a skillet inside the tent and only put it on it's lowest setting. It provides all the heat needed to keep the inside of the tent well above freezing.

Note in the first photo below the blue tent. This is an old car cover I had. I just draped it over the green metal stakes. As you can see in the second photo, the clusia shrub and Ti plant are unscathed!  Note the electric skillet. I would remove the car cover during the day, as it was so easy to do, so the plants could get sun. It  only took seconds to reinstall the car cover at night.

6mil tarp and 1x1 for support. Works but also bbn worked as an oven. I'm pretty sure all my damage is from them cooking from a freak hot morning.

[kinzyjr]

For now, this will suffice at my location since my palms are all under 10 feet:

 

[sandgroper]

13 hours ago, Walt said:

You are welcome. I once read somewhere (can't recall now) that palm can be covered (blocked from sunlight) for an extended period of time, say 30 days, or more, without any adverse effect. I can't recall, though, what the reason was for wrapping the palm in the first place. It may have been palm hobbyists that were trying to grow palms far outside their cold hardiness range, and would then cover them for a long period during the winter months.

Yes, once a palm gets too big, it's not practical, if not practicable, to protect the frond crown. Being in the northern hemisphere, my cold air normally comes out of the northwest. I rarely have a advective (windy) cold event that damages foiliage on my palms. 95% (if not more) of the time my palm foliage is damaged from a radiational (no wind and clear sky) event. If it's windy, there's virtually nothing you can do to protect a palm canopy on a larger palm.

But what I've tried to do in the past, with some success, is to install a PVC tarp wall 360 degrees around a palm or plant (I have photos somewhere, and if I can find them I will post them). Then, I direct a forced air propane or kerosene heater into the tarp area. Even though the tarp wall may not be as tall as the palm, the heat, naturally rising, helps protect the foliage and keeps frost from forming. But, as you can imagine, is a laborious installation, and costly too, if you run a heater all night long.

But over the years I had to give up on trying to protect the entire palm(s), and now only protect the trunk and meristem. Fortunately, I don't have to do this every winter. It's been about six years since I've had to protect my palms' trunks and meristems. 

BTW, I'm on well water, which is relatively warm (24C). I generally will saturate the soil around my coconut palm so that more heat can be released from the soil at night and rise up into the palm's canopy (on radiational cooling nights). And I've also got up 2-3 times at night and applied more warm well water to the soil (my soil is basically sand) so to add heat to the area around my palm (coconut). 

Sounds very similar to what I've done with my coconut, the polycarbonate sheeting only extends to around half the height of the palm. Inside I have a small heater set on a timer for the coldest nights, I also have 4 black plastic tubs filled with water to act as a heat trap during the day, two of these have aquarium heaters running as they use very little power to maintain a temperature of 32c in the tubs. We had the coldest temperature  since August last year this morning, it dipped to 3c. Is supposed to be 19c today so that will help. 

[Walt]

On 6/29/2018, 10:26:19, mdsonofthesouth said:

6mil tarp and 1x1 for support. Works but also bbn worked as an oven. I'm pretty sure all my damage is from them cooking from a freak hot morning.

Yes, during the day your protection acts as a greenhouse. I have a greenhouse that I used to overwinter potted palms and tropical plants in. One a sunny winter's day it could approach 100 degrees in it. My greenhouse was covered with a 6 mill UV rated poly. It acted like a magnifying glass. I had two doors (one on each end) that I had to open up during the day to keep the temperature down. In the summer I had to put up some shade cloth to block out some of the sunlight, otherwise, even with the doors open it would get too hot.

[sandgroper]

It is surprising just how much heat is generated inside these greenhouses, they really are effective. 

[Walt]

On 6/29/2018, 12:05:12, kinzyjr said:

For now, this will suffice at my location since my palms are all under 10 feet:

 

I would have still covered the tops (ends of fronds). What I do on palms that size is bundle them (with rope, twine, etc.) then tie a 1" PVC pipe or wooden furring strip, etc.) to the palm, just a little longer than the top of the fronds (like shown in your photos). The pipe is then use to carry the static weight of the blankets, wraps, etc. I take a corner (say of a king size flannel bed sheet) and loop it over the pipe, then wrap several layers of the sheet around the palm. The more layers the better, as air in between each layer  acts as an insulator. 

In any event, what you did is far, far better than doing nothing at all. Even bundling a palm and not wrapping it (like you did) is better than leaving a palm spread wide open to the air and frost.

[kinzyjr]

2 minutes ago, Walt said:

I would have still covered the tops (ends of fronds). What I do on palms that size is bundle them (with rope, twine, etc.) then tie a 1" PVC pipe or wooden furring strip, etc.) to the palm, just a little longer than the top of the fronds (like shown in your photos). The pipe is then use to carry the static weight of the blankets, wraps, etc. I take a corner (say of a king size flannel bed sheet) and loop it over the pipe, then wrap several layers of the sheet around the palm. The more layers the better, as air in between each layer  acts as an insulator. 

In any event, what you did is far, far better than doing nothing at all. Even bundling a palm and not wrapping it (like you did) is better than leaving a palm spread wide open to the air and frost.

A great idea for improvement, @Walt  I tie the fronds first, then wrap a towel from about midway up the small palms down to the ground.  A second towel is wrapped from the top to the bottom.  2 layers is usually good enough.  I had some damage, but the spear is fine.  If we get a 1980s freeze, I'll probably tent them.

Down the road, another guy had coconuts and didn't cover them.  One is definitely in the mulch pile, the other has some small fronds but will likely die this winter if it doesn't kick the bucket sooner.

[Walt]

This was my coconut palm as protected (trunk and up past meristem with heating cables and insulative wraps) on the first morning (December 7, 2010) of the string of freezes. This was the earliest frost I've ever observed in the 20+ years I've lived here. Note the frost on house roof.  I covered all my ixora shrubs with multiple layers of flannel sheets.

Foliage damage had not yet begun to show up, as I took these photos early in the morning. Sebring FAWN recorded a low of 31.15 degrees F, so it probably dropped into the high 20s at my place, which almost always runs a few degrees colder, being on lower ground.

This cold event lasted until December 16th (the final cold morning), before a warm up began. By then there was pure foliage devastation to my garden.

 

 

 

[Walt]

5 minutes ago, kinzyjr said:

A great idea for improvement, @Walt  I tie the fronds first, then wrap a towel from about midway up the small palms down to the ground.  A second towel is wrapped from the top to the bottom.  2 layers is usually good enough.  I had some damage, but the spear is fine.  If we get a 1980s freeze, I'll probably tent them.

Down the road, another guy had coconuts and didn't cover them.  One is definitely in the mulch pile, the other has some small fronds but will likely die this winter if it doesn't kick the bucket sooner.

I see people around my neighborhood with frost/cold palms that are small enough that they could protect them easily -- but don't. The next morning or two after the frost/freeze their palms are straw colored, some eventually die. Some palms, when severely  cold damaged, although they may not die, they never grow normally again. I've seen it with many species of palms I've grown that were cold damage. It seems the growth rate reduces to one fourth or less the normal rate.

I've found that just covering a palm, protecting it from frost,  the palm can take probably at least five more less degrees on the foliage.  And if string lights are used or heating cables, along with good insulative wraps, the palms can withstand almost any kind of over night cold we are liable to experience in central Florida. If supplemental heat is used (string lights, heating cables) the heat doesn't have to be all that much if really good insulation wraps are used.

 

[Walt]

Moving up to the morning of  December 15, 2010, you can see my bananas are toast. My coconut palm's fronds are severely burned. I even used a 30,000 BTU kerosene forced air heater to help protect the fronds. It made about as much difference as fart in a whirlwind -- when my low temperature dropped to 22.1 degree F that morning. This is why I gave up on trying to protect the fronds. I just concentrate on protecting the trunk and meristem.