The bonsai is a miniature tree that is cultivated from a young, regular-size tree. Like regular-size trees, the bonsai requires dedciatged watering for healthy growth. Mastering the watering requirements of the bonsai tree can be the most difficult process of bonsai cultivation. The watering schedule must be created to match each individual tree's needs and required moisture levels.
Check the moisture level of the bonsai's soil before watering by placing your finger 1 to 2 inches into the soil near the roots. If the soil feels somewhat dry to completely dry, it is time to water the plant. Bonsai trees are intolerant to excessive moisture and are susceptible to root rot.
Water the bonsai tree in the early morning and at the same time with each watering. The tree may not require daily water, but it does require ample time to absorb the water before the day's higher temperatures arrive. Never allow the bonsai tree to dry out completely.
Use small amounts of water initially to determine how much water the tree needs. Start with about a cup of water for smaller trees. Check the soil's moisture levels every three to four hours, placing your finger in the soil. Add ½ cup of water if the soil feels dry. Take note of how many additional ½ cups are added throughout the day.
Begin the next day's watering with the total amount of cups that were used during the last watering. Be sure to check the moisture level before the watering. Continue to check the levels throughout the day.
Soak the tree to promote good soil moisture by submerging it in a sink filled with tepid water. Leave the plant in the pot, covering it and the base of the plant with water until bubbles stop rising. This may take several minutes. Remove the tree from the water and place it in a cool, warm location for several days. Check the moisture levels daily. Perform this step when you are unsure of the soil's moisture levels. Do this no more than once per season.
Avoid developing a routine watering schedule for the bonsai, as its needs will vary. Continue to check the moisture levels daily. This will be required throughout the life of the tree.
Adjust the amount of water as the climate changes as the bonsai will require more water during the hot, dry summer months and less during the fall and winter. Pay close attention to the watering levels, especially in the spring as the moisture requirements will fluctuate greatly.
Mist and dust the tree's foliage regularly to promote healthy foliage and increased humidity. The foliage requires water as well. Irrigate outdoor bonsai trees from overhead to provide water to the foliage during watering. Always avoid overwatering.