How frequently should I water annuals in containers?
The frequency of watering may vary considerably from container to container. Watering frequency depends on the size and type of container, composition of the potting mix, plant species, and weather conditions. Some plants, such as impatiens, like an evenly moist soil. Others, such as vinca, possess good drought tolerance.
Annuals growing in containers should be checked daily (especially in summer) to determine if they need to be watered. A few plants, such as New Guinea impatiens and fuchsia, should be checked twice a day (morning and late afternoon or evening) as they dry out quickly on hot, windy days.
When watering annuals in containers, continue to apply water until water begins to flow out the drainage holes in the bottom of the container.