Providing proper soil moisture (or lack of moisture) is important in caring for a Sansevieria. The number one cause of yellowing leaves among Sansevieria plants is overwatering. Sansevieria basically thrive off of neglect–they don’t need much water to survive. Only water when the top 50% of soil is dry. Water until water flows freely from the drainage hole at the bottom of the pot. Be sure to discard any excess water that flows into the saucer. Your Sansevieria doesn’t like “wet feet,” as this can lead to root rot and eventual death of your Sansevieria.
Your watering consistency
Alternating between bone dry and wet soil from ill-timed waterings can create stress and cause your Sansevieria to have yellow leaves.
Weakened or stressed Sansevierias become more susceptible to insect infestations. Sap-sucking bugs like spider mites can drain your plant of moisture. This problem quickly manifests itself by yellowing leaflets and fronds. Scale, mealybugs, and spider mites occur frequently in indoor conditions. If not killed early on, these small pests proliferate and move all along the leaves and blades. The piercing mouths of the insects exhaust your plant and accelerate yellowing, especially if your Sansevieria is already unhealthy from a nutrient deficiency or improper soil moisture.