How and When to Water Bonsai Trees

Learning how and when to water your bonsai tree is a bit more tricky than knowing why to water.  Watering provides H2O, carrying nutrients and fresh air into and washing excess gasses away from roots.

One for the pot, one for the soil, one for the tree.

There’s a Japanese adage that goes: water three times – one for the pot, one for the soil one for the tree.  With that in mind, thoroughly watering your bonsai’s root system and soil through dunking or three-times watering, ensures your pot and potting medium will soak up their maximum capacity.

With the proper porosity, unneeded water will drain, allowing nutrients and oxygen to be absorbed, avoiding dry soil pockets that can starve fine hair roots, eventually dehydrating and killing them.


Top Recommendation - Haws Watering Cans

Gentle Rain 

Surface watering is best accomplished using a fine rose fixture, facing up, that causes an even, rain-like sprinkling and avoids blasting the soil from the top of your medium.  Watering a bonsai with either a watering can or fitted hose is not as important as the thorough, gentle process.

There are a number of considerations to take into account as you come to understand when to water your bonsai.  Some of these are:

  • species

  • size of pot

  • nature of soil

  • drainage/aeration

  • evaporation

  • time of year

  • rate of growth

  • wind

  • sun, shade or shelter

If you’re looking for one ideal watering pattern or schedule, put that thought away.  Water too much, you’ll rot the roots; water too little, they’ll dry out and die. 


Read Related Article - How To Choose Bonsai Fertilizer 


Your bonsai is confined to a pot and does not have the where-with-all to self-regulate its water source.  As water is taken in through the roots, dispersed throughout the body of your bonsai and released through the foliage, the above considerations and conditions can influence your day-to-day bonsai watering.

Determining what watering needs your bonsai has can be accomplished by:

  • checking the surface

  • probing just under the surface – approximately 1/2”, by touch or chopstick

  • lifting your pot

Does it work?

Again, what you use to determine when you plant needs water is not as essential as - does it works?  If you consistently have withering leaves, drying branches or other indications of too much or too little water, change your strategy.  However, be consistent long enough to decide that this method is effective before you change methods, again.

Being consistent and flexible, you’ll learn to water your bonsai when and how it’s needed, rather than based on someone else’s imperatives.   

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