From my perspective as a begonia, the question of watering is the most critical aspect of our relationship. I don't operate on a human calendar. My need for water is a constant dance between thirst and suffocation. My roots crave both moisture and oxygen. When you water me too much, you drown my roots, filling all the air pockets in the soil. Without oxygen, they rot, and I cannot absorb water or nutrients, leading to my decline. When you water me too little, my cells lose turgor pressure—I wilt, my leaves crisp, and my growth stalls as basic processes shut down. The goal is a moist, but not soggy, environment for my root system.
You cannot simply water me "once a week." My water consumption is influenced by several dynamic factors. Light is my primary driver; the more bright, indirect sunlight I receive, the more I photosynthesize and the faster I use water. Temperature and humidity play huge roles. A warm, dry room will cause moisture to evaporate from my soil and through my leaves much faster than a cool, humid one. The season dictates my growth cycle; in spring and summer, I am actively growing and need more frequent watering. In autumn and winter, I am resting and need much less. Even the pot I'm in matters—a porous terracotta pot wicks away moisture, while a glazed ceramic or plastic pot retains it longer.
The most reliable way to know if I need a drink is to physically check my soil. Ignore the surface, as it can be deceptive. Please insert your finger about an inch to two inches into the potting mix. What does it feel like? For most begonias, like my popular Angel Wing or Rex cousins, you should water me when the top inch of soil feels dry. For my tuberous friends, who are more susceptible to rot, you might wait until the top two inches are dry. Another excellent method is to lift my pot. After a thorough watering, feel how heavy I am. Lift me again every few days. When I feel noticeably light, it's a clear sign that most of the water has been used up and I'm ready for more.
When you have determined that I am dry, please water me thoroughly and thoughtfully. Use room-temperature water to avoid shocking my roots. Pour water evenly over the soil surface until you see it begin to run out of the drainage holes at the bottom of my pot. This ensures my entire root ball has been moistened. This is crucial. Let me sit in the sink or saucer for about 15 minutes to ensure I've absorbed all I can, then discard any excess water that remains. I must never be left sitting in a saucer full of water; this is a one-way ticket to root rot. This cycle of thorough watering followed by a period of drying out is the rhythm I thrive on.
