From the plant's perspective, the primary concern is root health. Snake plants (Sansevieria) are equipped with rhizomes—thick, root-like stems that store water. This adaptation allows them to thrive in arid conditions with infrequent rainfall in their native habitats. Consequently, their roots are highly susceptible to rot when forced to sit in waterlogged soil. A pot without drainage creates a bathtub-like environment at the bottom. After watering, excess water has no means of escape, saturating the soil and enveloping the roots. This constant moisture fosters anaerobic conditions and promotes the growth of root rot fungi and bacteria, which will attack and decay the rhizomes, ultimately killing the plant.
Plant roots require oxygen for respiration, the process of converting stored energy into usable forms for growth and function. Well-aerated soil contains pockets of air that facilitate this gas exchange. When a pot lacks drainage holes, watering displaces this vital oxygen with water. The soil becomes compacted and airless, suffocating the roots. Drainage holes serve a dual purpose: they allow excess water to exit and, just as importantly, enable fresh air to be drawn down into the pot as the water drains. This cycle is essential for maintaining a healthy root zone where the rhizomes can respire efficiently and remain healthy and firm, rather than becoming soft and mushy from rot and oxygen deprivation.
Over time, minerals and salts from both tap water and fertilizers accumulate in the potting mix. For a snake plant, a buildup of these elements can alter the soil's pH and, in high concentrations, can become toxic to the roots, causing "fertilizer burn" and hindering the plant's ability to absorb water and nutrients effectively. A pot with drainage holes provides a natural flushing mechanism. When you water the plant thoroughly until water flows freely from the bottom, this action helps to dissolve and carry away these excess salts and minerals, preventing them from concentrating in the soil to harmful levels. A pot without this outlet allows salts to accumulate unabated, creating a increasingly hostile environment for the root system.
A scenario that can work for the snake plant involves using a decorative outer pot (a cache pot) without holes that contains a separate, slightly smaller nursery pot with drainage holes. From the plant's viewpoint, this setup is acceptable because it provides the required drainage. After watering, you can lift the inner pot out of the decorative container, allow all excess water to drain away completely, and then place it back inside. This method protects the roots from standing water while still allowing for an aesthetically pleasing display. However, it is crucial to never let the inner pot sit directly in any water that has collected at the bottom of the cache pot.
