This really varies due to variety of reasons. Factors such as the nature of the plant, weather conditions, soil quality and its location are also affected. Therefore, it is important to consider for all these factors while watering. Generally, plants growing in warmer climates need more water than cooler climates. Most of plants prefer moist soil to thrive. Plant size is also determined how much water your plants. However, too much watering cause to root rot whereas lack of watering cause to grow leggy plants.