Soil heating for potted papayas?

[Daintree]

I always have trouble in the winter with potted papayas in my greenhouse. Although the temps in the greenhouse are in the 60's, the papaya roots want it a lot warmer.
To get a jump on it, I am planning now.

I have several ideas so far -
1. wrap Christmas lights around the pots (difficult to control temp)
2. set the pots on seedling mats (will they provide enough warmth? Pots would be easy to move)
3. put soil warming cables in the pots (will make it difficult to move the pots, since the cable is long so I would hook several pots together)
4. make a heated sand bed using the warming cables and set the pots on it (would it get warm enough?)

Has anyone ever tried any of these? Any suggestions would be appreciated!

Thanks!

Carolyn

[brian]

Christmas lights/heating cables inside larger terracotta pots, and set the papaya containers inside those pots?  That let's you move the papayas, but you still have terracotta big pots that can't move easily.  Not sure if that is any better

[Jaboticaba45]

How big are your trees? I had a 6 foot tree that did well in my greenhouse(doesn't go below 50 degrees and no root heating)

[Daintree]

These are babies, but I have grown them up to six or seevn feet. All winter, they just sit there and look pathetic, even with extra light.

[SeaWalnut]

There is a special heating cable made of semiconductor cable from carbon.That heats up only to about 80 C and its the same material thats used in heating mats.
You could get somme of that cable and add it in 2 circles inside the pot.
This is somme good cable and you can see its cheap but i reccomend having a GFCI as a main switch on the pannel of the greenhouse.
The joint between the carbon fibers and the regular copper wires should be  OUT OF THE POT.
https://www.ebay.com/itm/Infared-Underfloor-Heating-Cable-12K-33Ohm-Heating-Wires-for-Floor-Warming/264217567000?_trkparms=aid%3D1110011%26algo%3DHOMESPLICE.DISCLISTINGS%26ao%3D1%26asc%3D225118%26meid%3D7397a776e7154024a1244b1186f741a7%26pid%3D101096%26rk%3D2%26rkt%3D12%26sd%3D264115924007%26itm%3D264217567000%26pmt%3D1%26noa%3D0%26pg%3D2332490%26algv%3Ddefault&_trksid=p2332490.c101096.m3021
Use a well insulated cable and have an GFCI protection switch no bigger than 10 Mah for the greenhouse electric pannel.
If you dont know what is a GFCI,its a device that prevents you or your pets from electric shocks and its the same type of circuit breaker thats used in Jacuzzi baths so that you dont get electrocuted if the electric part fails.
You can look at your electric pannel and if you see a small button with a ,,T,, on it on one of the circuit breakers ,means thats the GFCI( just 10% percent of the homes have such advanced protection in the most developed countryes).
In case you dont have one,you can buy one with your electrician.
Now if you can read on the GFCI thats 30 mAh or 10 mAh even better ,you then have a good anti electrocution protection.
See the little white button with a T on it .T its for test and if you push it the GFCI should jump because it simulates a short circuit.They are expensive,i paid 50 dollars equivalent on the GFCI and 1 dollar on the rest of T&G ( made in China  ) circuit breakers.

[Daintree]

Thanks. Heating cables were one of the things I was considering, but if I use a really long cable then the pots are hooked together and harder to move.  If I use several short cables then the cost is higher and I have to deal with more cords. 
And good grief, of course I know what a GFCI is. In the US, they are required by law in damp locations, outdoors, in the kitchen and the bathroom etc. I also have a spreadsheet calculating every amp and watt that is used in the greenhouse, so I know what to put on which circuit.

Cheers,
Carolyn

[SeaWalnut]

You use this only for a few pots.
I made a drawing for you with a plan .
I forget to write that the pot should be as small as possible for the plant to grow and be happy( estimative) and that the insulation layer with foam should be @ 3 cm thick.
Carbon wires dont need a thermostat like old metalic heating cables so they are dirt cheap as you dont have to use a thermostat for each cable and each pot.


That GFCI soo sensitive wich protects all my home circuits not just the bathroom its soo rare and smart that even the people that sell electric instalation parts here dont have such thing at their home.
I have such a radical electric protection installed in my home because i have saltwater aquariums and i keep a lot of salt water at home wich its much more dangerous and much more conductive in case of an electric shock than fresh water.