Watering... first learned, last mastered

I often hear from a lot of people, including Ryan, that watering is the first skill learned and the last one mastered. I’m curious what nuances, techniques and/ or observations you all have learned later in the game (however long your “game” has been) about watering. I’m sure it’s quite broad and species specific stuff but I’m hoping this thread may help open doors for some observation skills.


First time using top dressing for me, so I’ve kinda been watching that and watering when it starts to get dry. It’s been working well for me so far. Down side is that it seems that birds have taken to pecking around in it and I’ve had to reapply it to to various spots on one of my quince three times in this week. :rage:


It doesn’t get easier.
40 years of bonsai, and I’m still learning nuances. Still killing the odd tree now and then through sheer ignorance.
I water three times. Once for the soil, once for the pot, and once for the tree. Adjust for each specific situation. Skip trees that like dry. Skip trees that have moisture retain soil.
Usually once per day in spring and fall. Up to three times in high summer. Adjusting for nuances. TALK to your trees; and LEARN to listen!
Do NOT forget winter moisture. IF your trees are in a shed, water them… If you use a greenhouse or a ground hoop, watch for moisture saturation and vent as needed. Outside, snow into pots protect from roots freezing. If they warm up, there is water available. Tarp only when needed.
Watering is:
Species specific.
Soil specific.
Tree / pot size specific.
Drainage of pot specific.
Time of year specific.
Temperature and humidity specific. Put a thermometer in a
full sun pot. Keep track of upcoming weather.
Full sun specific, full shade specific.
General map area specific, and microclimate specific.
If your tap water is nasty… fix it, or do something else. pH,
salts, metals, chlorine… etc, etc, etc. This gets deap real
quick. Keep it as simple as you can; AND dont freek out
about it. Tap water is usually fine.
Notes to self:
Some species need wet, some want dry. Keep track.
Planting in water retaining / draining soil helps, only if you keep track of each.
Don’t over water bristlecone. They always die.
Don’t leave shohin (very small tree in very small pot) in 90F
sun, especially South facing windows. They are dead
before you water them.
Don’t leave new buys in the black plastic pot in full sun. The
roots fry and they are dead next spring.
If a fancy pot only has one drain hole, it will stay wetter.
If you are in extended raining conditions, tip the slow drain
pot, or protect the trees.
If your slab or fancy rock planting doesn’t have drainage
holes… figure it out. I have successfully used a siphon
tube on a rock basin.
Moss! Top dressing to grow moss. Then learn to adjust
FOR the moss! Pots will stay damper!
Keep local trees, they survive better in your area. Pay
MORE attention to your non local trees…
I move ALL of my trees into shade (cloth) when extended
temps hit 85F. At zero humidity and 95F, they are dead in
3 hours. Pot temps hit 110F. Roots fry. They look green,
but, are dead next spring.
NEVER GO ON VACATION! If you do, make shure your
minder has the training, time, and attention span… Always
keep a good supply of beer… Don’t place blame when
random trees come up dead…
Automatic watering systems work great; until they don’t…
I love my new Gingko, how the heck do I keep it alive!!!
Did I miss anything…? Everyone has his own survival strategy. Figure it out, then share.
Bonsai on!
(AND, don’t freak out. Keep it simple. Bonsai is rewarding, and amazes ME every day! )


That is one of the best posts I’ve seen on watering and the nuances of it.

I think what is often overlooked is how watering applies to whatever you’re about to do to your trees. People frequently ask: What soil composition, particle size, how much can I prune, when should I prune, can I repot now, how much to root prune, etc. What almost NEVER gets asked it how I need to change/adapt my watering to fit said action. If you prune a lot of foliage water won’t leave the container as fast, if you have small particle size you might need to water less. If you watered 1 time a day you might need to only water once every day and a half which then begs the question “Can I do that while I’m at work” etc.

This list is also drastically different depending on where you live. I live in the Mojave Desert, so as mentioned things have to go under shade cloth at a certain point of the year every year, also putting my shohin in a pumice tray full of water helps if I’m not able to get to them soon enough. Shallow pots are another way to help keep moisture in as well as moisture retentive soil components.


@KurtP I love the plug for a good beer supply snuck in there! haha

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I need to add one important point.
ALWAYS pay attention to the BACK of the pot. Water it , too!
I have all of my trees where I can water from both sides.
Facing east / west, to catch morning and evening sun. Mid day has a 70% shade…during extended summer temps above 85F. (Except ponderosas and large pines…)
I also rotate pots frequently. Makes a significant difference!
I still catch large pots that are dry on the back side,
Bonsai On!


Summer has been rough on my top dressing this year. It’s been tough for me to strike that balance of keeping the top dressing moist and alive, while not overwatering. Much of my top dressing has dried out because of the really hot days we had a couple weeks ago. Some of it is bouncing back, others still look dead. The trees seem fine though!

I guess I still on that watering quest. Finding that balance…and not causing root rot, because I love to water! :stuck_out_tongue:


I have given up on the top dressing for the summer.
The sphagnum moss WALLS I built on several pots are holding up nicely.
Most of my pots are devoid of green moss, too. Some have huge chunks here and there. Oddly, my large alpine fir pot is compleatrly covered in moss…
One added THOUGHT to my watering rant… Don’t water your bristlecone pines at (almost) all… My (3rd) tree does fine almost dry. Killed the others by watering them with the decideous scheduale.
This summer is the first time my pines went yellow from over watering, though. Way too hot and dry early. I backed off a lot. They are mostly dry before I water them. Surviving well. My very large Ponderosa are a different bent. The pots are deep enough if I don’t water on schedule, the bottom 2 inches are bone dry. Look crazy healthy. They like slightly dry and 90F. The pot/ soil has not got above 85F.

Haha, you and me both man. I’ve kinda resigned myself to the fact that my top dressing is never going to be a lush green carpet of moss. Especially in my full-sun spots where it tends to dry out. I also have a wind factor which dries out the top dressing well before the soil.

I’m still having to re-apply due to pesky birds, so I’ve taken to having two bags of top dressing. One bag that’s a dyed sphagnum and shredded moss mix. The other bag is just dyed sphagnum. I use one or the other accordingly.

I’m getting the hang of water, but just barely. I’ve killed at least two to three trees this year due to my hydro affection. :sob:

Killed my blue spruce, but idk if it was water, high humidity, high heat or all three. :man_shrugging:t4: My solution: no more spruce of any kind.

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Heat… not the water. I live in a ‘desert’. Dry n hot summers.
The spruce are up in the mountains… cool.
I only have one (out of 6) left.

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