Winter protection - Polycarbonate or plexiglass type covered frame?

[BayAndroid]

So I'm thinking ahead about winter and I am considering building some small frames (my palms are young) with 2x4's or something similar and placing a sheet of polycarbonate or plexiglass on the top as a roof to stop frost from falling on the palms. 

Has anyone got any input on the effectiveness of this? I figured this way the palms would get some light and these protection measures might look a little less obvious in the front of my property. The original plan was to just throw a plywood piece on top as a solid wood roofing option, but that wouldn't look as nice. 

Opinions? 

[Merlyn]

Technically frost doesn't "fall" onto anything.  Frost forms because the top surface of the plant (or any other object, really) is radiating heat towards deep space at absolute zero (0 degrees Kelvin).  That rate of heat loss is dependent on whatever is between the plant leaf and deep space, which is why frost doesn't normally form on cloudy nights.  And if there is dew or rain it's much more likely to form.  On a cloudless night with no wind you can get frost ul to about 38F, though obviously it is more common near or below freezing.

Physics matters because anything that gets in the way of that radiation will stop frost from forming.  Essentially a 32F plant leaf radiates to absolute zero, a delta of 273K.  A piece of plywood (or any other material] in the way should prevent frost from forming on the plant.  The plant radiates towards the 32F plexiglass (0K difference), and the plexiglass radiates towards deep space (273K difference).  Frost forms on the plexiglass, but not the plant.

[Las Palmas Norte]

6 hours ago, BayAndroid said:

... Opinions? 

You're on the right track with a polycarbonate panel for a roof. I've seen posts on forums where this has been done with success. It won't offer any temperature protection, just light frosts won't form on the fronds.

[SeanK]

If you're building cold frames, it should work fine. If the space is closed, some heat will come from the ground. I would look for a "plastic" that blocks some sunlight, so plants don't fry on a sunny day.

[BayAndroid]

5 hours ago, SeanK said:

If you're building cold frames, it should work fine. If the space is closed, some heat will come from the ground. I would look for a "plastic" that blocks some sunlight, so plants don't fry on a sunny day.

Only if the box is closed, correct? I was thinking of just trying an open structure, but keeping the top covered. However, maybe I do need to trap heat. I'll consider some options as there's still a lot of time for planning. 

[Merlyn]

@BayAndroid if the sides are open then the palms should be protected from frost, but will have no temperature benefit.  If you have fully sealed sides it'll be a bit warmer inside, like a greenhouse.  But even small gaps can reduce the effectiveness pretty fast.  As an example I put a couple of cardboard boxes over palms last winter.  Outside my IR thermal scanner showed ~28F and inside the box it was 3-5F warmer.  It was enough to reduce some cold damage...maybe.    But the biggest advantage of the box was preventing frost.

[flplantguy]

I turned a shadehouse into a greenhouse this way. You can use the polycarbonate top and plastic drop cloth sides rolled up. Drop and clamp them shut at sundown (or sooner if its really bad)  and open again at dawn.  You can place hand warmers inside or larger jugs of hot water depending on the size.  The greenhouse i had was a 10 by 40 foot space on concrete against the house so only the hot growing orchids were heated the other half was only the cover and latent heat.  I flowered prize winning orchids in it but summer heat was a big problem with the roof. This setup you suggest is more mobile and can be used only on the night its needed too.  Just dont let the palm fronds touch the plastic sides if you can.

[Fishinsteeg234]

@BayAndroid two years ago I had the same idea of building a simple square framed structure with just a shade cloth over the top to help against frost in winter. Once I started with the square frame, I quickly decided a few extra 2x4’s and switching to polycarbonate would be a better long term investment. After a few YouTube videos and a half dozen trips to big blue box store spending 100$’s of dollars later, a small greenhouse on my side yard was born. With the polycarbonate sheeting, I can control temperature, humidity, and sunlight more easily than just a shade cloth. Also, I had major issues with squirrels eating seedlings and had to create a varmint proof enclosure; this was my major driver for building a solid greenhouse while mid-construction. In total I spent close to 700$ in materials. During our central florida cold spells last two winters zone 9b (27 degrees) I can add a small space heater inside to keep things stable enough and still growing happily. Structure is about 8’x8’x8’ and I have two small openings at the top front and top back with chicken wire to allow airflow in (squirrels out) and these are easily covered with sheet plastic to hold temp/humidity on the coldest nights if necessary. I added an extra hose extension from my existing irrigation with inverted sprinkler wobblers for water, and a 40% shade cloth overtop until the mango and avocado trees can fill in for natural shade. Since building this structure, my palm collection and seed germination operation has exploded. I recommend building a small “solid” structure instead of just a shade cloth on top. My only mistake was I didn’t use pressure treated wood for the frame, so I will most likely have to rebuild in a few years. I am also looking for good shelving ideas for the inside to allow water to drain level to level. Hope this helps.  Here are a few pics from newly built, and now. 
 

[BayAndroid]

7 hours ago, Fishinsteeg234 said:

@BayAndroid two years ago I had the same idea of building a simple square framed structure with just a shade cloth over the top to help against frost in winter. Once I started with the square frame, I quickly decided a few extra 2x4’s and switching to polycarbonate would be a better long term investment. After a few YouTube videos and a half dozen trips to big blue box store spending 100$’s of dollars later, a small greenhouse on my side yard was born. With the polycarbonate sheeting, I can control temperature, humidity, and sunlight more easily than just a shade cloth. Also, I had major issues with squirrels eating seedlings and had to create a varmint proof enclosure; this was my major driver for building a solid greenhouse while mid-construction. In total I spent close to 700$ in materials. During our central florida cold spells last two winters zone 9b (27 degrees) I can add a small space heater inside to keep things stable enough and still growing happily. Structure is about 8’x8’x8’ and I have two small openings at the top front and top back with chicken wire to allow airflow in (squirrels out) and these are easily covered with sheet plastic to hold temp/humidity on the coldest nights if necessary. I added an extra hose extension from my existing irrigation with inverted sprinkler wobblers for water, and a 40% shade cloth overtop until the mango and avocado trees can fill in for natural shade. Since building this structure, my palm collection and seed germination operation has exploded. I recommend building a small “solid” structure instead of just a shade cloth on top. My only mistake was I didn’t use pressure treated wood for the frame, so I will most likely have to rebuild in a few years. I am also looking for good shelving ideas for the inside to allow water to drain level to level. Hope this helps.  Here are a few pics from newly built, and now. 
 

Wow, that is very nice. Good work! Mine will be more of a temporary seasonal structure, but I was considering a more permanent style greenhouse; like this. 

[Hardypalms]

Here in my 7b i wrap c9 lights around (Not touching anything green) my palms and turn them on around 40.

Then if we go 30, i put frost clothes around everything.

If below this with rain i also add a tarp.

My full grown ,Sabal palmetto, Butia capitata (Not full grown), Chamaerops humilis( 5 feet tall) and Serenoa repens survive with maybe 10-20% leaf burn for some which they recover fast starting end of February.

I do not protect at all Sabal minor (Don’t grow large for me for some reason but give hundreds of seeds) and R. hystrix (4 huge ones. Birds nest in them).

I did not protect my Full grown Trachycarpus fortunei (2 of them from seed by me, kinda proud of this lol) and they took a non fatal beating in last winter 1 week arctic blast.

I m currently building PVC frames (Real tall) for both T. fortunei’s and will throw tarps above using long poles along with C9 according to weather.

Lots of work in the winter after an exhausting day at work, often working in the dark with my wife but I m not losing them by negligence.

 

Next i will add a full grown Washingtonia, they sell full grown mule here too but they are expensive, really large and probably more tender than the rest i have.

I m growing Chamaedorea radicalis from seeds and will experience keeping some shaded (Understory palms) and protected under my talk back porch from the elements when they are a little taller With extra protection) crown shafted palm surviving a 7b winter would be neat.

 

My tropics in 7b

Pat

 

 

 

 

Edited August 27, 2023 by Hardypalms

[The Palm Nut]

On 8/11/2023 at 10:02 AM, BayAndroid said:

So I'm thinking ahead about winter and I am considering building some small frames (my palms are young) with 2x4's or something similar and placing a sheet of polycarbonate or plexiglass on the top as a roof to stop frost from falling on the palms. 

Has anyone got any input on the effectiveness of this? I figured this way the palms would get some light and these protection measures might look a little less obvious in the front of my property. The original plan was to just throw a plywood piece on top as a solid wood roofing option, but that wouldn't look as nice. 

Opinions? 

Not really relevant as our climates are different but back in the day when I would try growing those really exotic tropical palms, I used a bird cage. with great success. Then after a few years or so the bill for electricity became an issue, hate to think what it would cost today. I enjoyed the challenge back in the day and still do but try to keep to the more realistic challenges and capabilities of the garden I have.

[Jeff zone 8 N.C.]

Ever tried one of these pop up camping showers? Cheap and easy to set up and take down. Bottom comes off so it can slide over the top of the palm. I have not tried them but they are cheap and easy so maybe you can be my test case. LOL. There are others available so maybe other colors or manufacturers types would let more light in. At that price I would not expect longevity from exposure to strong sun.

https://www.amazon.com/Portable-Changing-Collapsible-Wakeman-Outdoors/dp/B07WWYQS7B/ref=sr_1_3?keywords=small%2Bpop%2Bup%2Btent&qid=1693186064&sr=8-3&th=1

Edited August 28, 2023 by Jeff zone 8 N.C.