Are these guys just sitting out on a balcony or stairway landing? Theoretically those plants can live through a freeze. In fact the vfts need a cold winter dormancy, or so I'm told.

Two options I can see: 1) leave outside but bundle them up well to protect from extremes. Put them in a dry container and insulate it the best you can. Put it next to a building wall where it might get some heat. 2) wrap them in plastic and store them in your refrigerator the rest of the winter.

To be honest, I have a horrible long-term survival record with vfts, possibly because it doesn't get very cold here in winter. I'm almost resigned to treating them as annuals, because they go downhill as fall approaches and never recover. And I wouldn't worry too much about the pitchers, either, because lately they have gotten so cheap stores are almost giving them away. I got two amazingly healthy specimens at the 99 Cent store just a few weeks ago, and another that looks like a Hindle for $1 at Lowes on the distressed plant shelf. Now it looks just as healthy as any other of my pitchers, better than some in fact.

Basically out on the deck (a ground floor balcony). My worry is that we've been down to the single digits at night a few times.

I put a thermometer on my windowsill yesterday -- inside the apartment, on the windowsill I currently have my strawberry seedlings, it gets to mid 50s during the day and down as far as the low 40s at night (probably lower to be honest, I checked when I woke up at 9 AM). Maybe I should try moving the VFTs to that windowsill?

I could, in theory, crack the window a little bit to let some more cold in to drop it even further...

You might move it to the window sill, but cracking the window to warm it might be going too far. Maybe you can get a sheet of clear plastic or something to tack above the window, then allow it to hang down so it shields the plants from the cold and also retains some of the heat leaking out the window. That may be redundant according to the laws of thermodynamics, but you get the drift, I hope.

Also, you can build a "cold frame," basically a simple, small greenhouse. I'm sure you could find DIY instructions all over the Net.

No, the worry is that they won't be cold enough in the window, not that they'd be too warm. A Cold Frame isn't an option for my environment, maybe once I buy a house in a few years...

My windowsill is internal, I can't put them on the outside, just inside the actual apartment.

It's not the cold that is killing your plants. It is dehydration. The plants are literally becoming freeze dried. VFT's, Sarrs, etc. can withstand freezing temperatures. Purpurea can be found way up north in Canada.

However, when you grow these plants in pots you are not shielding the soil and root system from freezing temps as thier natural habitat does. As a result, during extended periods of below freezing temps, the entire pot freezes solid which makes the water unable to be absorbed by the roots. These plants are dormant, but they still absorb water as water escapes through thier leaves.

I have many sarrs, vfts, drosera filliformis and live in Zone 5 (Indiana). What I typically do is bring my plants in my unheated insulated garage. It is typically 10-15 degrees warmer in there than outside during the winter. I only bring my plants out during days that it is above 30.

What I would suggest is trying to find some way to keep the plants above freezing (30s-40s). If you do not have access to an unheated garage or attic (next to a sunlit window if possible) then another method would be to but the plants in a large container and put mulch over them. Pine bark, leaves, pine needles or something to that effect. This will shield the plants from arctic blasts and keep moisture from escaping too quickly. Check every week or so to insure the soil is still moist.

Hope this helps...
Some other good resources on the web for dormancy are www.cobraplant.com and www.cpukforum.com

I brought the 2 VFTs in. One was dead, it was not deep enough in the pot at all. The other has some green left, so I am hopeful.

I have some foam planters from flytrapshop, once the remaining VFT de-thaws I plan on repotting it in there.

I would wait until spring to find out if it is dead. As long as the bulb is OK then it should sprout in the spring. It won't hurt to care for it until spring...

Should I cut off any black or brown leaves?

I am currently water-sprouting some Drosera cuttings, wonder if I could take the tiny bits of green left on this plant and water-sprout them...

Yes, just to prevent fungus. As long as the bulb if OK, you will see new growth next spring.

It's too late now, but I wouldn't recommend thawing them out quickly. That might shock it. Putting them in the fridge for a few days until they are thawed would work when temps stay in the below 20s for extended periods of time.

The pot can stand to be frozen solid for a few days. It is when they are frozen for extended periods with no protection that dehydration is a possibility. Mulching helps stop water loss. A styrofoam cooler would work with leaves, bark, etc over the top. Check moisture every few days.

Hope this helps. Good luck.

I brought them in a few days ago, and took a look inside last night. The bulb was completely black and dark brown. Dead.

The tragic thing was it was ready to be divided 3 times over, I could have split them before putting them out and had a backup plant.

I do have a small VFT I got from a local grocery store about a month ago, I have taken a leaf pulling of that and put it in the box of water with my Drosera cuttings that are water-propagating, not sure if a leaf pull will work for that, but, we'll see.

I feel bad about losing my first VFT, but... Learning experience I guess. I still have my first Cape Sundew which I bought at the same time, so... yeah.

I still have 5 Sarracenia out there that I'm worried about, they're not changing colors so I think so far so good, but... yeah.

The 3 White Trumpets (2 standard 1 "Judith Hindle") are in one big 12" pot, said pot has a bottom layer of LFS and a top layer of LFS, their bulbs are right in the middle of the LFS, so... kinda worried about them too. I have 2 S. Purpurpea (1 northern 1 southern, I believe) out there as well.

They all seem to be wilting a little but keeping the same colors, so, here's hoping that they're ok.