From the perspective of the cyclamen plant, the primary concern is the health and integrity of its crown and tuber. The crown, the point from which leaves and flowers emerge at the top of the flattened tuber, is exceptionally susceptible to rot. When water is applied from above and pools in this central crown, it creates a persistently damp environment. This moisture fosters fungal pathogens like Botrytis and accelerates the process of crown rot, which is often fatal. The plant's physiology is simply not adapted to handle standing water at its most vital growth point. Furthermore, the leaves and flowers themselves can be damaged by water spots or develop mold if they remain wet for extended periods.
The cyclamen's root system originates from the bottom and sides of the tuber. These roots are designed to draw water upwards. Bottom watering, where the plant is placed in a saucer of water and allowed to absorb moisture for 15-30 minutes, directly caters to this natural design. The roots pull water up through the potting mix via capillary action, hydrating the entire plant efficiently without ever wetting the crown or foliage. This method ensures the moisture is distributed evenly throughout the root zone, encouraging strong, deep root growth as they stretch downward toward the water source. It is a self-regulating process; the plant absorbs only what it needs, leaving no excess water in areas where it can cause harm.
Cyclamen prefer a "moist but not soggy" growing medium. They are particularly sensitive to both overwatering and complete drought. Top watering makes it very difficult to achieve this balance. It is challenging to ensure water penetrates evenly throughout the pot without some areas becoming waterlogged, especially if the soil has become slightly compacted or pulled away from the edges of the pot. Bottom watering eliminates this guesswork. The dry soil actively wicks water upward, ensuring a thorough and uniform moisture level from the bottom of the pot to the top. Once the surface of the soil becomes visibly moist, the plant has absorbed sufficient water, and any remaining water in the saucer should be discarded to prevent the tuber from sitting in water, which can lead to root rot.
While bottom watering is overwhelmingly preferred, a cyclamen would acknowledge one specific scenario where top watering is beneficial. Over time, soluble salts from fertilizers and tap water can accumulate in the potting mix because bottom watering does not flush them through and out the drainage holes. A high concentration of these salts can burn the delicate roots and harm the plant. Therefore, it is advisable to occasionally, perhaps every fourth or fifth watering, use the top-watering method. Water should be applied slowly to the surface of the soil, allowing it to drain freely from the bottom, continuing until you have flushed a volume of water equal to the pot's size through the soil. This leaches away the excess salts, protecting the root system, but must be done with care to avoid wetting the crown.
