How cold are we talking about? What kind of potting mix? Did you buy them recently, from where, and could they have gotten chilled going from the store to the car to your home? Are they round black spots in the middle, or brown tips on the ends of the leaves?

It was pretty nippy out the night that I bought them....won't be buying plants late at night again! So I am hoping that I have now fixed the problem. I potted them into too large of a pot plus too much water....when I pulled them to downsize to smaller pots tonight there was defintitely standing water in the bottom (but no root rot yet YEAH!)....so I also changed from plastic to terra cotta which should help with transpiration...took it light on the watering this time since we are in the middle of winter. Plus put pebbles in terra cotta saucers with a little water to go under the plants and help with humidity.

I also downsized the other dracaena and the maranta which I had purchased a week prior to the other two dracaenas...the maranta had standing water in it which could explain why I was losing some of the red color on it...the dracaena which I said was the healthiest looking of the three had the driest soil and no blemishes. So I will be crossing my fingers to see if that was the problem...if not I probably have a fungus problem, but only time will tell I guess.

So as a newbie to house plants, I guess I have a lot to learn....went and got a book on houseplants and today picked up an iresine herbstii, a peperomia caperata, a peperomia obtusifolia, and a handful of cacti and succulents (haworthia, crassula, aloe, drunkard's dream)....they are all babies so at least if I kill them all I didn't spend a fortune. And I had the pleasure of realizing during the process of potting down tonight, that the maranta and the dracaenas have all grown since I purchased them. But they all look much better in appropriate sized terra cotta pots. Wish me luck on my new adventures with houseplants!

Sounds like you're on the right track - good luck!