Begonias generally prefer moist but well-drained soil and should be watered when the top inch of soil feels dry to the touch. The watering frequency varies depending on factors like the type of begonia, pot size, soil, climate, and whether the plant is indoors or outdoors.

• Indoor Begonias: Water when the soil surface is dry, typically once or twice a week during the growing season (spring to fall). In winter, watering frequency should be reduced as the plant enters dormancy. Avoid wetting the leaves to prevent fungal diseases

• Outdoor Begonias: They usually need watering every 2 to 4 days, but in hot, dry climates, watering may be needed every other day during warm periods. In cooler or more humid conditions, watering twice a week may suffice. Ensure the soil drains well to prevent root rot

• Young Begonias: They require more frequent watering, possibly daily, to keep the soil consistently moist but not soggy. Mature plants need less frequent watering and should be watered based on soil dryness

• General Tips: Use well-draining soil with some compost to retain moisture but avoid soggy conditions. Water deeply enough to reach the roots and allow excess water to drain out. Overwatering can cause root rot and fungal infections, while underwatering leads to wilting

In summary, water begonias every 2 to 4 days outdoors, or once or twice a week indoors, adjusting based on soil moisture and environmental conditions. Always check soil dryness before watering to avoid overwatering.