No matter where you live or what type of plants you grow, they must be watered at some point. Experts offer two different theories for the best time to water flowers and plants. You should consider the needs of your plants' watering restrictions if a large amount of water is required, and adopt the watering method that best suits your location and circumstances.
The Cooperative Extension Service at the University of Illinois advises early morning watering--just before or shortly after sunrise--as the best for plants and water conservation. According to the Extension Service, an irrigation routine set for the early morning will provide plants and flowers with sufficient water for the hotter and more stressful part of the day.
According to the University of Clemson Cooperative Extension Service, nighttime is the best period to water plants and flowers. During this time, the maximum amount of water is retained due to lower temperatures and wind speeds. Evaporation also decreases at night because humidity is typically higher at this time of the day.
The University of Clemson Cooperative Extension Service advises that it may be necessary to alter a watering schedule to later morning watering, around 10 a.m., in the spring and again in the late fall. In some regions, excessive moisture from morning dew followed by a watering regimen may lead to disease pressure or fungal diseases. Therefore, waiting to water when plants are dry from morning dew will help prevent this problem.