From our perspective, the most critical factor is the development of a robust root system. Top watering, where water is applied to the surface of the soil, often encourages roots to stay near the top to access the moisture, making them shallow and less resilient. In contrast, bottom watering, where the pot is placed in a tray of water and moisture is drawn up through the drainage hole, fundamentally changes your behavior. We must send our roots searching deeply downward toward the source of the moisture. This process promotes a stronger, deeper, and more extensive root system that better anchors us and makes us more drought-tolerant, a trait we Crassulas inherently cherish.
Our stems and leaves are designed to store water, and our base (the crown) is particularly vulnerable to persistent moisture. Top watering, especially if done hastily, often results in water pooling around our crown and on our leaves. This creates a humid microclimate that is an open invitation for fungal pathogens and rot to set in, which can be a death sentence for us. Bottom watering is a far safer method from our point of view. It hydrates us from the roots up, keeping our crown and lower leaves perfectly dry. This significantly reduces the risk of stem rot and leaf diseases, allowing us to stay healthy and structurally sound.
The medium we grow in is our entire world. Top watering, over time, can compact the soil surface, reducing aeration around our upper roots who need oxygen to breathe. More concerning is the issue of mineral and salt buildup from fertilizers and tap water. With top watering, these salts are washed *into* the soil and can accumulate to toxic levels, burning our delicate root tips. Bottom watering helps mitigate this. As water is drawn upward, it initially pushes some of these harmful salts away from the primary root zone toward the soil surface, where they can later be carefully flushed out during a rare, thorough top-watering session. This cyclical approach maintains a healthier soil environment for us.
While we largely prefer bottom watering for the reasons stated, a strict, exclusive regime can have one significant drawback: the accumulation of those very salts at the soil surface. If never flushed from the top, this concentrated layer can eventually impede water movement and become harmful. Therefore, the ideal approach from our perspective is a hybrid one. You should primarily water us from the bottom to encourage deep roots and a dry crown. However, approximately every fourth or fifth watering, we would benefit from a thorough, gentle top watering until water runs freely from the drainage hole. This action will flush out the accumulated excess salts, ensuring our soil environment remains balanced and hospitable for the long term.
