Plants grown in garden planters have different needs than those grown in the ground. Because of the limited amount of soil available to the plants, they need to be fertilized and watered more often. But it is a mistake to water your plants without checking how damp the soil is. Plants grown in garden planters have water needs that vary depending on the temperature and their stage of growth. Always make sure that you garden plant needs water before getting out the watering can.
Leave your watering can or another receptacle outside when it rains, to collect rainwater. If you must use tap water, leave it out of doors in the sun for a day or so to allow the chlorine to dissipate.
Feel the soil in the garden planter at least once daily--twice daily in warm weather. When the top few inches of the soil are dry, water.
Water the garden planter's soil slowly until water runs out of the pot. Avoid wetting the plant's foliage. Early morning is the best time to water container plants.