Sarah put up a pic of a plant with a deficiency in zinc (primary problem) and possibly Mg as well. That can come from lock out especially from too much bloom food with phosphorous in it- or if you use bone meal too aggressively.
In a cellar, you HAVE to get your plants up off the floor so the soil is not being chilled. That will certainly cause problems in uptake of nutrients, and give def-like symptoms. Then many growers will try to fix that by feeding, and end up with burn, too! Ow. Post pics when you can.

In the meantime, the trick to a plant enduring cold temps is:
-Lighter soil- more perlite than usual
-Keep pH VERY stable in range- 6.7 and don't allow to go out of range! Cold+wet+acid=dead
-lift plants off floor
-water less than a plant in a warmer environment
-keep an eye on %rh and do not allow dewfall at ';night'
-seedling heat mats cost about $20-25 US each and are good for 2-gallon pots or 6-quart pots each (12x24"). They are wonderful.