The best time to water your garden is usually in the morning to maximize the efficiency of water used. This is because mornings tend to be cool, without strong winds, so the amount of water lost to evaporation is much less, than it would be during the day when it is hotter. What about the evening your say? Well, the evening is typically cooler like the morning, but plants then can stay damp over night and are more likely to be damaged by fungal and bacterial diseases.