The amount of water a garden needs depends upon climate and weather conditions. Where summer rains are frequent, the garden may need irrigation only during an occasional dry spell. In parts of the arid West and Southwest, watering is one of the gardener’s biggest chores.
Monitor weather conditions, especially rainfall, to be sure your plants are receiving adequate water. Some flowering annuals, such as impatiens, recover remarkably from an occasional oversight in watering; others can be set back badly by neglect.
For best results, annuals need a constant supply of moisture to provide abundant flowers. A deep soaking is far better than frequent, light applications of water. Deep soakings help plants develop deep, strong root systems, able to withstand some neglect.