So pretty, Kate. You are a zone higher than me, because you're out on the island, surrounded by water. At this time of year, we cool off a bit more (I am maybe a mile inland) because the water is still quite warm, but come January into early February when the Gulf is cold, it doesn't make as much difference for you. So if you can set something up for cold night protection now, you will Be Prepared! when it's even cooler.
Here are pictures of a trellis I have with some orchids mounted on it. I roll the frost cover up out of the way in the daytime and when I'm not using it. The watering cans get filled with hot water before I go to bed to give just a bit more warmth under the frost cloth. Plus a little humidity.
Another alternative, if you do start to have problems with cold damage. I now have 3 of these little shelf units that come with a clear plastic cover so it becomes a mini-greenhouse. Got the first one online, but now Home Depot and Lowe's carry them. Again, the water containers act as heat sinks to hold some heat from the sun through the night. (the water has coffee grounds in it)
Last night for the first time I tried what's known as a tea light heater, made with one tea light candle under a clay pot with a little foil cupcake liner over the hole so the heat will be dispersed. It worked absolutely perfectly. Just the tiny bit of heat inside the mini-greenhouse kept things above 60deg. all night, and one of the tealights was still hot this morning at 7am! I did get large tea light candles at IKEA that last for 9 hours.
