Each bonsai tree is different. Some trees like lots of water all the time, others like to dry out a bit in between watering. It is difficult to determine how much water your tree needs without looking at it, but there are some general watering tips you can follow to ensure your tree is getting enough water. We will now be going over how much water is too much water, when you should water your tree, and how to water your tree. 

How Much Water is Too Much?

If you are constantly overwatering your bonsai, you will be able to tell. Overwatered trees generally have yellowing leaves and their smaller branches will begin to shrivel and die. Overwatering one time won’t hurt your tree all that much. It is the constant drowning that will kill your tree, and it can take a few weeks.

Your tree may also be overwatered because of the soil it is planted in. Very water-retentive soil can keep hold of too much water in the roots. Bonsai trees should be placed in well-draining soil. Well-draining soil will help prevent root rot, which is a big bonsai killer.

When Should I Water?

To avoid over- and under-watering, it is always recommended to water your bonsai when the soil gets slightly dry. Instead of watering on a routine, check the soil every day to see if your tree actually needs to be watered. You may also need to check the soil a few times a day during the hot summer months.

As for the time of day, it doesn’t really matter. Some experts suggest not watering your bonsai in the afternoon with very cold water. This is because the soil will cool down rapidly after being warmed in the afternoon sun. You can take this into consideration, but you should always water your tree when the soil gets dry, no matter the time of day. 

Checking Bonsai Soil

Before watering your bonsai, it is crucial that you check the soil first. This will prevent overwatering. There are several different ways to check your bonsai’s soil.

The first method you can use when checking bonsai soil is using your finger. Simply insert your finger about one inch into the soil. This method may work, but we recommend using the methods below as often as you can because this method is often unreliable, especially if the soil is cold or if you are checking multiple bonsai’s soil.

The chopstick method is a more accurate way to check the soil. Insert a chopstick an inch or two into the soil. After 10 minutes, take the chopstick out and look at it. If the chopstick is discolored, the soil is still wet and should not be watered. If it is dry, it is time to water your tree. Clean after each use and store in a dry place.

Using a moisture meter is another good way to check bonsai soil. Insert the probe down to the root level of the tree. The meter will give you a number on a scale from one to ten, one being the driest, ten being the wettest. Any number under 4 means the soil is dry and needs to be watered. Any number 4 and over means your soil is wet and does not need to be watered. Clean after each use and store in a dry place.

How Do I Water my Bonsai?

So now you know when to water your bonsai, but how do you actually water your tree? When watering your tree, you are not just watering the soil, you are also wetting the entire root system. To ensure that the root system is wetted when watering, water until the water starts to drip out of the drainage holes at the bottom of the container. Then, a few minutes later, repeat this once more. 

Water your tree using a fine nozzled watering can. Using this watering can will not disturb the topsoil or fertilizer. We recommend collecting rainwater and using this to water your bonsai, but using tap water will work just fine. When using tap water, however, leaving it out overnight will ensure that any chemicals that may have been in your tap are gone. 

While each bonsai tree is different, some bonsai trees do like lots of water, but some like to dry out in between each water. Over-watering and under-watering are big bonsai killers, but can be prevented with well-draining soil. Be sure you are checking your tree’s soil before you water.