We are expecting some single digit temps this weekend in the New England area.  We've had roller coaster temps from 30F to 50F  down to 24F but its the lack of snow cover and the high winds that can dry out and kill you plants.  I moved everything into the cellar for the weekend.  Even my older fig trees.

They were all still outside up to this point?

Finally getting snow on a stretch. Tonight and for the next 5 days, forecast is for light to wet snow. Daytime temp warming to mid 30's and nights to low 20's or under 20F. Almost all my bigger trees in 10 or more gallon size pots are left outside. They are tuck just beside the house, south facing.

Oh ok, it's been warmer then usual here, but I brought everything in the garage a long time ago. We have had some really cold days already. I was just curious why they would still be outside if they are dormant, but if it's not cold enough inside yet to store them...

I have quite a number of large pots, some are in large cedar barrels. Shortest route & easier on the back as I don't need to pack & arrange them in the garage.  Also,  I have spares and likely when the smaller spares are producing, I will give the big ones away. Its getting harder every year to relocate the big pots with their feeder roots and I have a tendency to add more plants to larger pots. I have been getting free larger pots from friends & sometimes landscapers or pick them(used) from recycle bins located at garden centers for gardening pots.

I heard of someone who sprays their  trees with water and lets a sheet of ice form around them. Says never had a problem and when it melts, he just resprays when it gets cold again. These are in-ground trees. Supposedly never had a problem.

Dominick, I've heard that same technique is some with grapevines for frost protection.

They do it often (spray water) in Florida to protect their citrus fruits during a damaging freeze.

It has something to do with water acting as a heat/cold - "buffer";

specially around floating temperatures freezing point  (+/-  32*F).

In my old physics_101 classes, it was called "latent heat"...

(extra heat is given/taken when any substance changes from its solid/liquid state)

Also, the ice may act as a "shield" against any further (pure) cold and/or (desiccating) wind?

(BTW, I have never done this procedure on anything)

The phase transition from/to solid/liquid certainly requires extra heat input/output.  This is the process they take advantage of in FL citrus.  In that case, they're trying to prevent any plant tissues from dropping below 32 and freezing, as that will damage and/or kill the trees fairly quickly.  So they're using it to prevent the trees from freezing at all during a very mild frost spell (think 28 or 30 degrees overnight low).  They're effectively creating a tiny microclimate around each tree that is at or slightly above freezing.  And even if a little water freezes, that will happen from the outside in, so the water will freeze first and possibly spare the tree.

Certainly it would be a different principle in the case of spraying a fig tree with water when you know it is all going to freeze, thereby using up all the phase transition heat.  Once it is ice, the temperature will fluctuate with outside temperatures fairly quickly.  It may be effective at preventing tissue damage in non-citrus trees though.  I'd be interested to hear the theory behind it.  Is it to prevent dessication, like George suggests?

You all are correct to one degree or another. The site http://www.ifas.ufl.edu contains a vast amount of information on the subject. The two publication links below explain short term freeze damage control. The first deals with blueberries, the second with citrus. The publication for citrus covers more of the science.

http://edis.ifas.ufl.edu/hs216

http://edis.ifas.ufl.edu/ch182

zone 9b central Florida

Thanks navillus,

The web sites you pointed out are very informative about the subject.

Looks like I get to dig shuffle again this weekend... Lows in the 20s.... Saw that comin from a mile away....

Copy that JG. Expecting low 30s and high 20s this weekend here.

Well old man winter is back. I spent today moving everybody back into the garage. Tonight and Sunday night it is suppose to be below 32F and almost all my trees have broken dormancy. Frost is projected in z9b. Anybody else have a sore back. 

26 tonight and 29 tomorrow.

So much for the kind winter.

If you water to form ice you MUST continue through the freeze event. The protecton only occurs IF ICE IS BEING FORMED FROM WATER CONVERSION TO ICE. Once the energy conversion ceases the ice and what it is covering will rapidly adjust to the sub freezing air temp. The water not frozen is the buffer not the ice. You must continue watering till the air temp is above freezing AND the water has melted all the ice that formed on the branches. By the way the ice that forms is not your friend and as it builds it gains weight and will break your branches.