I once read “watering bonsai trees takes years to learn”. How strange, I thought. Why would it take so long to learn such a simple thing?
The truth is, watering bonsai is not as simple as it may sound. And yes, it may take years to get it right. One of the main reasons is bad information in the beginning.
We are bombarded with instructions that vary so greatly, no wonder the novice is confused. The following statements are just a few examples of such varied watering instructions.
- From an HGTV program on bonsai:
“Bonsai likes it on the drier side, so don’t over-water.”
- From an early U.S.D.A. brochure:
“Water your bonsai every day.”
- From a bonsai nursery (not to be named):
“Water your bonsai every three days.”
They can not all be right!
Watering Bonsai How-To
If you prefer a hose, attach a nozzle set on any setting low enough not to disturb the soil.
They are especially valuable when you ask someone else to water!
If you only have one or a few bonsai . . . hand watering using a watering can with a good rose head on it, is one of the best ways.
There are many variables when it comes to watering any container plants, especially bonsai trees. These are a few of the basic questions to ask:
- Species of plant – Do they by their nature like to be wet, moist or almost dry?
- Type of potting soil – Is it coarse and fast draining? If so, it may need water every day. Or, is the soil heavy, drains slowly, and therefore stays wet longer?
- Size of container? – Small containers dry out faster than large ones.
- Location – Indoors? Outdoors? Growing in the shade? Or sun?
- Time in Pot? – Containers full of roots dry out faster than newly potted ones; even when they are the same species.
No matter the method of watering bonsai you select . . . water enough so the water flows through and comes out the holes in the bottom of your bonsai pot.
To be sure all soil is moistened, water twice. Allow the first to ‘sink in’, then go back and water again.
Be wary of instructions to “water every day” or “every other day” or “every third day” etc. !!
Watering bonsai instructions should read something like “keep evenly moist”, “keep wet” or “allow to dry out a little between waterings”.
Watering bonsai too much can be as big a problem as not enough. It’s important that plants are not over-watered. Be especially careful with succulent plants such as bonsai Jade.
How often should you water? Many beginners will not like this answer . . . . . .
Indoors and Out – the Real Answer
Water as needed for the specific type and size of plant you have!
As you get to know your bonsai, you will be able to just look at them or pick them up (and tell by their weight) to know whether they need water or not.
Some, who have many bonsai, have automatic irrigation systems of one type or another. While living in Miami, I had a timed overhead sprinkler system (leftover from my nursery days.)
When you develop a large collection or have a nursery, automatic systems are certainly an option. I ran my system once a day in winter and twice a day in summer. I also seasonally varied the length of time for each session.
During the rainy season, I often turned it off and watered certain plants by hand.
Automatic irrigation is not without problems. They can break down, can be inconsistent in different zones, create too much water when it rains and they do get clogged from time to time.
The automatic drip system on a timer
What About “Dunking”?
Bonsai watering by immersion is not always a good idea. If your tree is completely dried out, it may be a good quick fix. However, frequent immersion can compact the soil. This can cause root damage.
If you find it is necessary to “dunk” on a regular basis (because water is not being absorbed otherwise) . . . your bonsai may need repotting, AND most likely it needs to be in a different soil mix.
Coarse, fast draining type bonsai soil is not as problematic with dunking.
If you think you have a soil problem … before you repot, make sure it ‘s the right time of year for the species of plant you have.
Reasons for Daily Inspection
Watering bonsai every day may or may not be necessary.
However, bonsai do need daily inspections!
Did an animal knock over a tree?
Was the wind really bad last night?
Did the watering system miss your favorite small bonsai?
What are those funny looking bugs?
Special Note: Watering Bonsai in Winter
Tropical bonsai are protected from frost and freezing temperatures indoors and in greenhouses. Be aware the watering needs will most likely change from what was needed outdoors.
Many other bonsai remain outdoors. When plants are dormant they consume very little water. The soil needs to be kept moist but not soaking wet. Heavy rains and melting snow can cause over-watering problems.
This is why many bonsai end up in garages and other protected areas. Read more about bonsai winter care.