Fretting about overwatering - a myth nowadays

[Clicio]

If one doesn't use those "humidity trays" to keep the bottom of the pot underwater full time, if one has the drainage holes unclogged, if one uses a good modern fast draining mix as a substrate...
Then there are no such things as overwatering and root rot.
In my modest experience, even using heavily organic soil in some of my trees (Jaboticabas, Surinam Cherries), no watering is too much,even for pines and junipers in full sun.
NOTES:
- Our winters are very dry.
- The Wisteria sits happily on a tray full of water all summer.
- In our summers the soil of all trees are dry after 5 or 6 hours of sun. Watering twice a day is a must.

So why so much panic about it? As a side note, I have killed a lot of trees, but never saw a root rotting.
Underwatering, I am sure kills trees.
Overwatering... I don't know.

 

[Forsoothe!]

Me, too. I've damaged trees by letting them get too dry many times, but "too wet" is only a problem in the greenhouse when the plants are dormant and cold. I've only seen root rot twice, both on trees I bought in autumn(s) that I didn't repot in my media because I got them too late in the season. In both cases, they were in akadama. All my houseplants are in jardiniere, -pots without drainage holes.

I have always been of the opinion that root rot is a product of planting trees in media that lack supporting microbiome because they are barren. My media is basically 1/3 top soil and 2/3 pine bark fines with no rocks.

 

[0soyoung]

Over watering = watering too frequently.
Leave the garden hose running into your shallow tray and your maple will suffer anoxia, regardless of the grain size (as long as the rate water comes out of the hose is faster than the rate it drains out of the holes in the bottom of the tray)

IOW, it all depends on the depth of the saturation zone and the depth of the pot. Supposing the pot is a lot deeper than the saturation zone, one cannot, for all realistic intents, 'over water'. If the pot is approximately the same or less, it is quite possible to 'over water' -- that is, water too frequently, so frequently that the saturation zone is maintained and the roots drown (anoxia).

 

[0soyoung]

I have always been of the opinion that root rot is a product of planting trees in media that lack supporting microbiome

I use nothing but Turface MVP and Osmocote-Plus (sparingly). Nothing in it to support any biome (I suppose) yet mico shows up in my conifer pots. I must not administer enough P to discourage/kill them (as a high P environment is known to do), but I do nothing to promote them according to your hypothesis. No bark, nothing organic other than the tree roots themselves and whatever incidentally is in the air.

 

[bonhe]

Underwatering, I am sure kills trees.

I agree. If I am not sure, I’d rather overwatering than underwatering. I have been using this strategy when I was on vacation. I always went to vacation in the mid-summer for years and set up automatic watering system in overwatering setting with excellent results.
By the way, since you created this topic, I will have an interesting topic later on. Please check it out.
Thụ Thoại

 

[zanduh]

what I want to know is that if you are watering 2 times per day in the summer through an inorganic soil and you are using a constant low dosage of liquid fertilizer that is urea based are you getting a good absorption rate of the npk by the roots.

I’ve read a lot of different opinions and some scholarly papers that say that you need at least 4 hours for bacteria to convert the nitrogen and that inorganic fertilizers favor fungus in roots and organic fertilizers favor certain bacteria in the roots but I haven’t read any definitive studies on how much fertilizer is utilized in a fast draining substrate

 

[Carol 83]

I have killed Bougainvillea by watering too much while inside for the winter.

 

[Clicio]

I have killed Bougainvillea by watering too much while inside for the winter.

Hummm.
Bougies here never go indoors, they are tropicals in the tropics after all !

But I don't save on water when showering them. Plenty. Often.
But...
Outdoors.

 

[bonhe]

Hummm.
Bougies here never go indoors, they are tropicals in the tropics after all !

But I don't save on water when showering them. Plenty. Often.
But...
Outdoors.

I think she is living in cold winter area, it is why she has to bring it indoor.
Thụ Thoại

 

[Clicio]

what I want to know is that if you are watering 2 times per day in the summer through an inorganic soil and you are using a constant low dosage of liquid fertilizer that is urea based...

Soil; mostly inorganic.
Akadama, lava rock, perlite, but peat and pine bark in the mix.

Fertilizer: organic (Biogold), prills (Basacote), and @#$%&%€# stinky fish emulsion.

Plenty of water, plants all happy.

 

[Carol 83]

Hummm.
Bougies here never go indoors, they are tropicals in the tropics after all !

But I don't save on water when showering them. Plenty. Often.
But...
Outdoors.

Alas, IL is not the tropics. They usually have to come in by mid October. Outside, they get watered everyday and flourish.

 

[leatherback]

Overwatering... I don't know.

Don't forget: You are in the tropics, where it never gets cold enough to get trees to shut down.

Here in the far noth, we do get these periods of hovering around frost, Rain every day for several hours. Some trees have dificulty dealing with fully saturated rootballs at that time, and root can start to die off.

 

[Shibui]

I agree that killing trees from over watering seems to be way over rated. My experience is also that under watering is a much quicker way to kill trees and I also tend on the side of more water rather than less and the trees here still thrive.
I am suspicious that at least some reports of over watering being a cause of decline could be traced to ineffective watering leading to dehydration.

However I have seen root/trunk fungal trouble in Japanese maples occasionally. So far always associated with long periods of cold, wet conditions. That does not happen in summer when everything gets watered copiously twice every day whether they need it or not.

 

[Bnana]

With poor soil it is easy to overwater. Many trees you can buy come in a clay-like or very organic soil, this easily becomes anoxic and that can kill the roots.
I do agree that in proper soil this is unlikely to happen. Even when it is cold and raining a lot.

 

[Lumaca]

From the viewpoint of a beginner, overwatering seems like a more "permanent" damage while underwatering seem more reversible.

 

[Shibui]

Under watering can quickly lead to death, often just a single day is enough. Death is pretty permanent.
It is possible to recover a dehydrated tree provided you get to it in time. Some species do not show signs until far too late.
It is also possible to recover trees from root rot provided you get to it in time.

 

[YAN]

This spring I repotted some trees in coco peat, perlite, pumice 1.1.1 parts ( i added coco peat as i was worried about water retention) aummer here is very hot 35 C some days plants are under full sun.

result: i see fungus gnats if i water everyday so now i water every other day and they’re gone, im considering going all inorganic next spring so i can water everyday without worrying about overwatering, maybe crushed LECA, pumice, lava.

 

[Clicio]

Over watering = watering too frequently.
Leave the garden hose running into your shallow tray and your maple will suffer...

Yes, thanks! I am aware of the problem with shallow pots.
But...
If a tree is already in a shallow bonsai pot and not in a deeper training pot, then we can safely assume that the owner knows what he/she is doing and will not let the hose running on the pot all day. I hope.

 

[Clicio]

I have killed Bougainvillea by watering too much while inside for the winter.

Carol, I am very sorry for the loss of your bougie. Then I think "should it be indoors? Should it be in a colder climate than it is genetically engineered "? Which is another topic, of course. The flowers are irresistible, I know...

 

[Lumaca]

Under watering can quickly lead to death, often just a single day is enough. Death is pretty permanent.
It is possible to recover a dehydrated tree provided you get to it in time. Some species do not show signs until far too late.
It is also possible to recover trees from root rot provided you get to it in time.

Not gonna argue whether it was correct or not. Just trying to show how a beginner might feel that it is better to be on the safe (dry) side. I know that most people probably come from houseplant/succulent/herb to bonsai, and when you're hammered with "overwatering is the work of the devil" when you research care guides for any plant, the mindset kinda sticks.

Then you kill a few plants and the learning starts.