[FL] Does the "water before a cold evening" logic some (fruit or veggie) growers use apply to tropical bonsai?

[SU2]

Tonight's going to be the coldest of the year and I realized I've never found-out if the idea of hosing-down plants before a freeze applies to tropical bonsai before a cold evening? Any & all info on this, whether the concept/mechanism itself or just practical-application, is greatly appreciated! Was just going to water but realized I'm not sure if it's better - or worse - for me to have them wet before a cold evening, and furthermore whether dormancy-versus-growth plays into the considerations of hosing-down.....am inclined to believe it does, IE that my dormant/bare, established crape myrtles are already bare-branched, but some that I collected a few months ago are still in vegetative growth / haven't flowered yet, so unsure if, in the case of my crapes, the answer could be "depends on dormancy versus active-growth"!

Gotta love when it's the coldest month of the year for your zip and you're thinking about mid-40's as "ohmahgawd!!!", I've got a ~2wks old Ficus.B that I collected and have in a styrofoam box, am loving styrofoam boxes and wish I'd gotten into them sooner!! But that Ficus is my biggest concern for tonight, I'll be putting it in the screened-patio (with the temp and winds near 10mph, just seems smart to be safe, was a terrible time to collect obviously, was then-or-never like so many of my specimen!), it's a good 'example' specimen for this I think because I can basically count on the styrofoam container to keep the roots happy, yet the foliage is supple / active / not established-in-pot yet, it is actively growing (I have specific growing-tips I monitor ROFL, it is definitely 'going the right direction' since collection, had a thrip issue @ acquisition that was thwarted w/o chemicals in under a week)

Thanks a ton for any tips on this one, I have a small cold-frame but still haven't set it up (should probably get on that!), it's just been such a mild winter here, have been loving it for bonsai of course though!!

 

[JoeH]

Really? Its going to be 42 tonight, no need to panic. I just watered lightly as it will be low humidity and windy so stuff will dry out a bit. I don't overthink it or even worry about it till its a freeze warning, then I just toss my few tender things in the shed overnight. And why worry at all about Crepes? Just leave them out they will be fine.

 

[JoeH]

ohh, and the concept of strawberry and citrus growers watering during a freeze is to ice up the plants to protect them from getting any colder. The ice is like a blanket. I work at a citrus arboretum and they would just run the water all night in the event of a freeze prediction. That is just on the trunks we have no overhead water.

 

[JoeH]

 

[Shima]

ohh, and the concept of strawberry and citrus growers watering during a freeze is to ice up the plants to protect them from getting any colder. The ice is like a blanket. I work at a citrus arboretum and they would just run the water all night in the event of a freeze prediction. That is just on the trunks we have no overhead water.

I used to live in wine country (Glen Ellen) and I had always thought this practice was only used on grapes.

 

[Wires_Guy_wires]

In spring, nearly every fruit orchard over here uses water sprays as a frost protectant for fruit or flowers. Apples, pears, plums, cherries. But these plants are planted in the ground and not in pots. I don't know if this type of treatment is beneficial for bonsai in pots. My guess is that it's not.

 

[0soyoung]

ohh, and the concept of strawberry and citrus growers watering during a freeze is to ice up the plants to protect them from getting any colder. The ice is like a blanket. I work at a citrus arboretum and they would just run the water all night in the event of a freeze prediction. That is just on the trunks we have no overhead water.

That and a lot of energy (heat - the heat of crystallization) must be removed from the water to make it freeze. This keeps the plants from freezing even when the air temperature has moved below freezing. Of course, once the sprinkled water has frozen, its temperature will again drop toward the below freezing air temp, so keep sprinkling (more heat of crystallization to keep the plants themselves from freezing).

 

[JoeH]

That and a lot of energy (heat - the heat of crystallization) must be removed from the water to make it freeze. This keeps the plants from freezing even when the air temperature has moved below freezing. Of course, once the sprinkled water has frozen, its temperature will again drop toward the below freezing air temp, so keep sprinkling (more heat of crystallization to keep the plants themselves from freezing).

right, see the 47 second clip I posted to help SU2 understand. I doubt the concept will work for his tender tropical that he thinks are in danger from the low 40s se are getting today.

 

[Starfox]

Low 40's is like what, 4 deg C in real speak?
Running 80 percent humidity, that would just be watering your trees more than anything else.

I brought most of my trops in yesterday for a few days as it was supposed to be 1degC/33f last night and colder for the next few nights. Lounge room is like a jungle at the moment. I get that moving large amounts of trees are not always practical though.
Must order greenhouse.

 

[Anthony]

Heh heh, still trying to figure just who is a tropical tree.
Since practically all trees here are - Sub-Tropical.

However, it has become clear that with cold, it is root
sensitivity to cold.
Good Example is Serissa s., dies with 86 deg.F by day and
68 deg.F at night [ for around 8 hrs.] A zone 7 in the ground
in China.

Styro and Mica pots do insulate,

So any down here any with sensitivity, are going into styro or
mica.
Love this new stuff.
Good Day
Anthony

 

[Silentrunning]

My Ficus plants come in the house if the temp gets down to 55F.

 

[AZbonsai]

Nothing inside this year. I cover them all. Below freezing on a handful of nights. Seems to be working well. I have ficus/bougs in my mix of plants.
One of my landscape bougs burnt to a crisp. But it will come back...just a bit shorter.

 

[Anthony]

See Scott's images of Ficus b [ ? ] with snow on it.
Research is showing quite a few trees able to handle
below 55 deg.F

No Tropical zpne for China.

Now is this cold resistance for above the soil line of the tree
and a constant of say 70 deg.F for the soil ?
Good Day
Anthony

 

[AZbonsai]

I dont worry about anything until it reaches 45 degf

 

[0soyoung]

right, see the 47 second clip I posted to help SU2 understand.

Water has a huge heat capacity, which does as you described. Trees buried under snow stay warmer than the frigid overnight air temperatures of 'arctic climates'. My point to stuff like fruit was only to emphasize that the heat of crystallization is what does the magic in preventing freezing --> amplify what you presented.

I doubt the concept will work for his tender tropical that he thinks are in danger from the low 40s se are getting today.

Oh, absolutely, I agree.