The most difficult thing to learn in the art of bonsai is how to water the tree properly. Most beginners are so afraid of letting their bonsai dry out that they end up drowning it. Water is a plants life line and proper watering promotes a bonsai tree's growth. Therefore, it is extremely important to perfect the art of watering your little bonsai. Watering takes the most amount of time when growing a bonsai.
Soil in a bonsai pot dries up at various speeds depending upon factors like the season, temperature, pot size, type of soil used in the pot, species of the tree, its size and its growth stage. Each individual potted plant requires a specific watering method and the appropriate method is to regularity provide the plant with sufficient water once the surface soil in the pot has become dry.
All the trees that grow in the ground have an ability to adjust to the water that is available to them. If a tree does not get enough water, its roots will spread out into the soil until moisture is found, whereas the trees that grow in humid and damp areas will have shallow root system because of the easy access to moisture. However, in a pot where the soil is less stable than the soil in the ground, the bonsai's ability of regulating itself to the exposure of moisture is lost as it is unable to decide how much or how little water it will get. External influences also effect the tree and because of these factors the possibility of the bonsai drying out is greatly increased.
The circulation of fresh air in a bonsai pot is crucial as the tree also breathe while it absorbs water. Since the air gaps in soil vary in size, water flows through the large gaps and accumulates at the bottom of the pot and eventually drains out. In this process, the water pushes out the state air from the air gaps and allows fresh air to flow in. Sprinkling water only moisturizes the surface soil, while the deeper soil remains dry. So while watering a bonsai tree, care should be taken to ensure that sufficient amount of water is supplied so as to refresh the air in the soil and also to let water permeate down to the middle and bottom of the soil in the pot.
SUITABLE WATER FOR BONSAI
It is always better to water a bonsai with plain top water. If the tap water is hard and has chlorine, then allow it to sit overnight in the can, so that the chlorine evaporates and clean water is available. Rainwater, if available has lots of nitrogen in it and is free from impurities, hard water chemicals and minerals making it soft, which is very good for a bonsai.
HOW TO WATER A BONSAI
While watering a bonsai, ensure that the entire soil in which the bonsai sits is thoroughly soaked so as to avoid pockets of dry soil where roots could be left to dry out and die. When water flows, it involuntarily chooses the path that is easy to flow through. Therefore the water cannot easily permeate the soil in the centre. To prevent this, water the bonsai twice. First wet the soil a little so as to improve the soil's ability to absorb a larger volume of water. W0-ater the soil again thoroughly until the soil is saturated.
Another method is to immerse the pot totally in water until the bubbles stop coming out of the soil. But again this is not feasible for people who have numerous bonsai or large bonsais.
HOW OFTEN TO WATER A BONSAI?
The soil should be checked routinely to find out whether watering is required or not. The objective is to keep the soil moist which should neither be too soggy nor too dry. It is a balance between too much and too little. If the soil does not lose some of its moisture content between each watering, it means that the soil is permanently wet, which might lead to root-rot.
UNDERWATERING A BONSAI
If a bonsai gets too little water it will not be able to take sufficient nutrients from the soil. Through 'osmosis' roots absorb water from the soil. This water is then pulled up into the body of the plant and is released into the atmosphere through the foliage and this process allows the plant to distribute vital nutrients throughout its structure.
An underwater tree grows slowly and has brown, dry leaf edges. The bonsai may drop leaves or flowers or the tree may fail to flower entirely. When a bonsai receives too little water, the tree will conserve whatever little water it has by keeping the stem green and the roots moist, but the leaves will turn yellow and wilt and eventually dry up. It is the bottom leaves that suffer first.
OVERWATERING A BONSAI
When a plant looks unhealthy there is a temptation to water it more and often this is a mistake. This happens mostly because in many instances over watering resembles the signs of under watering. Poor drainage causes water logging resulting in dead roots because of non absorption of oxygen which is needed to function normally. The longer the air is cut off, the greater the damage.
A bonsai which is over-watered develops soft, rotten roots. The immediate effect to the tree is loss of vigour. Another sign of over-watering is that the tip of the leaf will turn brown. Another symptom is the presence of mildew, mould and other fungus which colonises the dead tissues and thrive in wet conditions. Over watering leads to stunted slow growth, new and old leaves of the tree become soft and will start to yellow and drop while smaller branches will shrivel and die back.
BONSAI WATERING TOOLS
It is advisable to use a watering can fitted with a fine nozzle to water the bonsai soil thoroughly without displacing the soil. Misting is a common humidifying method done by a misting can and helps in removing dust from the leaves, which blocks sunlight and interface with the exchange of oxygen and carbon dioxide. If a hose is used to water, ensure that the water pressure from the hose does not beast the oil out of the pots, in which case an adjustable spray nozzle is fitted so that soil is not displaced.