Farm Innovators Thermocube!  Found it on Amazon!

Some of the heating cables have built in thermostats.  I use these with mini incandescent Christmas lights.  

I know the OP was a while back but thought I would share in case someone has a similar question.

I have had good success using the standard propane patio heater w/ the 15lb tanks you find at Lowe's/ HD.  At 47K btu, they will empty a tank in about 8 hours so you'll want to set them on low when it is only 40 or so outside and increase as temps drop.  You can also remove the reflective shield if you need heat to get higher up for taller trees. Just yesterday, the temps dropped to <30F for a few hours- I placed a couple heaters near a coconut palm which has about 7' of trunk. Have another night in the mid 30s- will see if this works.

 

I purchased a number of patio heaters after a cold snap we had about 10 years back where the temps were <30 for about a week. Lost nearly everything.  The downside to propane heat like this is you'll need to get several heaters while will likely only get used 1 or 2 times a year if that. I am in zone 9b/10a. 

 

 

 

18 hours ago, TampaPalmNut said:

I know the OP was a while back but thought I would share in case someone has a similar question.

I have had good success using the standard propane patio heater w/ the 15lb tanks you find at Lowe's/ HD.  At 47K btu, they will empty a tank in about 8 hours so you'll want to set them on low when it is only 40 or so outside and increase as temps drop.  You can also remove the reflective shield if you need heat to get higher up for taller trees. Just yesterday, the temps dropped to <30F for a few hours- I placed a couple heaters near a coconut palm which has about 7' of trunk. Have another night in the mid 30s- will see if this works.

I purchased a number of patio heaters after a cold snap we had about 10 years back where the temps were <30 for about a week. Lost nearly everything.  The downside to propane heat like this is you'll need to get several heaters while will likely only get used 1 or 2 times a year if that. I am in zone 9b/10a.

Welcome to PalmTalk!

Getting ready for winter is always a smart move! Sorry for digging up an older thread, but I'm on the lookout for similar info.

On 8/31/2020 at 2:25 PM, Johnny Palmseed said:

Your problem is exactly why I stopped pushing my zone and just let nature run it’s course. I got old and grew tired of the hassle. Whatever I plant now must fend for itself.

You get my vote. Also why I suggest a 90/10 rule to growing palms. 90% are bulletproof where you live, 10% are marginal. As these get taller, protection gets harder. Maybe have your marginal be a Red Lipstick, and not a Coconut.

5 hours ago, BenSilver said:

Getting ready for winter is always a smart move! Sorry for digging up an older thread, but I'm on the lookout for similar info.

 

 

 

It sounds like you have a unique challenge with radiational cooling, especially in the coldest spot of your property. To generate artificial heat on those chilly nights, you might want to explore options like space heaters or portable electric heaters. They can quickly warm up a specific area and are quite handy when you need to boost the temperature.