Hey everyone. Recently planted a 15 gallon Phoenix Sylvestris. It's seemingly been doing alright but it looks like Monday for me there will be a low of 30 for a few hours until sunrise. I already anticipated making an enclosure and using lights for next winter when weather got too cold (it varies so much every year here its ridiculous). 

I've seen the Sylvester can "survive" down to 20 degrees. I assume that's for large established ones though. 

So I guess I'd just like to know at what temperature, or sustained temperature do most people decide to protect their palms? I know it will vary by region and palms but just in general. 

It should be fine, I don't have a sylvestris but do have a dacty in a pot I started from seed. It has seen 25f in a pot. It's probably a 2 gallon and it's fine. Sylvestris is hardier and yours is bigger and in the ground.

Phoenix sylvestris is a pretty hardy palm and you should have absolutely no problem at 30F for a few hours. If the palm is young and you get down into the lowest 20s for a while, you might worry that your foliage could burn (possibly completely depending on ultimate low, amount of exposure and the "wetness" of the freeze). I grew this species back when I lived in Natchez, Mississippi (chilly 9a) and it was fine down to about 20F. I ultimately lost it somewhere in the teens in a long, hard freeze when the tree was around 20' overall height and the bud was up in the air, exposed. That is the danger, when the palm has gone aerial with the bud in the air, rather than when they are young, and the bud is well insulated down in the ground where the surroundings are much warmer than the air-column.

On the more general front, every palm has its own needs in terms of cold-tolerance, and different regions have different effects on cold-hardiness of a palm, so there's no one-size-fits-all answer. But P. sylvestris is certainly hardy at 30F. You might want to go ahead and protect it if you're worried that your own temperature may go much below that 30F figure you're quoting...but I personally would never worry about such a temperature on pretty much any species of Phoenix (P. roebelenii being probably the most delicate in frosts/freezes).

Thank you both for the responses! I thought I looked into everything enough to be worry free before I bought it but something always comes up I guess lol.

 

@mnorell It's definitely not gonna do anything lower than 30. We're pretty much past that where I am. This may be the last night like this until next December so I think I'll be okay based on what you guys said. 

Frost in Alabama in March? Wow, who'd thunk.