Cold

• Snake plants can survive at a minimum temperature of 45 degrees Fahrenheit and are damaged or killed by frost. Cold conditions cause snake plant's leaves to turn yellow. Leaves that are touching window glass can develop yellow patches due to either cold or heat burn. Keep your plant far enough back from windows to avoid contact.
  
  

Overwatering

• Never leave snake plant containers standing in a dish of water and allow all excess water to drain out of their pots. Overwatering or waterlogging causes root rot in snake plants and can cause the whole plant to yellow and die. Reduce the amount of water you provide to snake plants during the winter. Water them in the morning so that any water on the leaves has time to evaporate before nightfall.
  
  

Underwatering

• Fred Dortort, writing on the University of California Botanic Garden website, comments that many snake plant species are close to indestructible. That said, a complete lack of water will cause their leaves to yellow before shriveling up. Water snake plants when their soil has dried out completely to a depth of an inch.
  
  

Insect Infestation

• Snake plants are vulnerable to attack by scale insects. They look like small bumps on the leaves and can cause leaves to yellow. Mealy bugs are similar to scale insects but look like they are covered in white fluff. Severe infestations of insects can cause snake plant leaves to yellow and die. Dab insect pests with a paintbrush dipped in rubbing alcohol, checking the plant regularly for any sign of re-infestation.