Metabolism and Photosynthesis: Water is essential for metabolism and photosynthesis, crucial for plant growth.
Nutrient Transport: Water transports nutrients to all parts of the plant.
Regulating Overheating: Plants transpire water through their leaves to prevent overheating.
Cleaning: Water cleans the upper parts of the plant by removing dust.

pH Value: The ideal pH value for watering is between 6 and 7.5. Neutral water has a pH of 7.
Salt Content: Good watering water is low in salt.

Tap Water: Let it stand for 24 hours to allow chlorine to evaporate and reduce hardness.
Spring Water: Check for harmful salts before using.
Pond Water: Regularly check pH and salt content.
Rainwater: Slightly acidic and low in salt, ideal for watering.

High Lime Water (pH around 7.5): Suitable for Taxus baccata, Cornus, Juniperus Sabina, Prunus, English oak.
Lime-Free Water (pH 4.5 - 5.5): Suitable for Azalea, Camelia, Rhododendron, Juniperus Chinensis, Picea, Larix.
Salt-Sensitive Species: Hornbeam, hawthorn, Fagus Crenata, Picea, Taxus baccata.

Morning: Water in the morning so the plant can absorb it before the heat arrives.
Evening: Watering is possible, but do it a few hours before sunset to avoid mold formation.
Midday: Avoid watering over the foliage of deciduous trees to prevent burning; conifers can be sprayed more often.

Vacation: Ask an experienced bonsai enthusiast to take care of the watering.
Obstacles: Do not hide trees behind bushes or other obstacles.
Rainfall: Adjust watering but be aware that rainwater doesn't always reach the soil surface due to the foliage acting as an umbrella.
Autumn: Reduce watering as trees lose their leaves and evaporate less.
Winter Storage: Further reduce watering but keep roots sufficiently moist. Use snow as an insulating layer on frozen root clumps.

Tree Species: From Acer to Pinus.
Origin of the Species: Natural habitat conditions.
Growth Phase: Including leaf mass.
Garden Layout: Presence of shade trees, water features, garden walls, bonsai benches, etc.
Tree Placement: On wooden or stone surfaces.
Climate Conditions: Varying temperatures and humidity.
Seasons: Seasonal changes affecting water needs.
Soil Mix Composition: Different structures and materials.
Pot Size and Depth: Influences water retention.
Pot Color: Dark pots get warmer and affect moisture levels.

Water Early: Water early in the morning before the heat.
Thorough Watering: Overwatering for a few days can be beneficial in extreme heat.
Dry Leaf Tips: Indicate too little water.
Burned Leaf Centers: Indicate sunburn.
Yellow Tips in Juniperus/Pinus: Indicate root problems, consider repotting.
Surroundings: Water the garden to create a humid environment.
Shohin Trees: Use a tray with pebbles and water to create a microclimate.
Cooling Pots: Use water and wet cloths to cool pots.
Shade Trees: Plant trees like linden for natural shade, or use shade nets.

Greenhouse Care: Pay attention to soil moisture as days lengthen and temperatures rise from January.
Evergreens: Monitor juniperus and pinus for continued growth and potential dryness in winter storage.

Source: bonsaidesigner.be

Bonsai Watering: an Art Form