Please help. Can they be saved?

I have never had this problem. There could be a number of things that could have happened. I had a freeze in the room and this is when the problem started. Temps made it down to 38f. Also could be nute burn as I thought it may have been a deficiency. Any help would be great before I chop them down and start fresh. Only half of the plants are doing this as well. Most strains that are acting up are sativa dominant. I have new leaves everyday that are dying off. Thanks for any help in advance.

If it were my grow, I would probably give them a good flushing, then start nutes again at 1/2 strength for a couple of weeks. JMHO.

you can try epsom salt i hear when the temps get real low it cannot intake potasium.1tblsp per gal.

To me that appears like a combo def....nitrogen and mag. To better diagnose check the stick...guide to nutes/def...in the marijuana problemz section.....man im getting tired of posting that last part

I have checked everything I possibly could. I can't seem to fix this problem. I shut off my co2 and brought my temps down to 74. The problem is getting worse everyday. I flushed them and the next day more leaves were browning. The only thing I can think of is when I supplemented co2 I didn't add enough nutes and they became deficient in multiple elements. I might try a foliar to get them the nutes they might need. anymore suggestions would be great.

Two thoughts.
1) Foliar feeding of ionics onto stressed leaves is not really a good idea. You are flirting with local chem burns, possibly severe.
2) It sounds and looks like irreparable damage induced by the cold snap. Sativas are of tropical origin; indicas hail from frost-prone mid-latitude deserts. Imo no nutrient adjustment can fix that.
cn

cannabineer said:

Two thoughts.
1) Foliar feeding of ionics onto stressed leaves is not really a good idea. You are flirting with local chem burns, possibly severe.
2) It sounds and looks like irreparable damage induced by the cold snap. Sativas are of tropical origin; indicas hail from frost-prone mid-latitude deserts. Imo no nutrient adjustment can fix that.
cn

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Would that mean these plants are done or would time bring them back to health in a perfect climate.

I guess that depends on whether or not the growth tips are still healthy&green. If so, time might bring them back to health ... very much time because you'll have to figure the yellowed parts as a dead loss. Jmo. Sorry I couldn't be more positive ... I know there's real pain in a grow gone south. cn