Watering from above or below?

[Dr3z]

I've already done a search and didn't find anything. Is there any reason to water from above rather than below? I know it might be impractical for larger trees but should work fine for shohin trees. Yet, I have seen in care section "water from above" at times which leads me to believe there is a reason. Contrary to that a nursery where I got one tree once recommended from below for good even watering for one of my trees but they admittedly don't specialize in bonsai. It's a common practice with succulents which also have draining soils similar to bonsai. Your wisdom is appreciated!

 

[sorce]

Lot of topping ferts need overhead watering.

Welcome to Crazy!

But you should water how it works.

Sometimes you must dunk soak a tree because it's the only safe thing to do, so keep it in the arsenal.

Lot of people will Repot a weak tree cuz regular watering doesn't work....then...regular watering becomes unnecessary because it dies!

Sorce

 

[Bonsai Nut]

The advantages of watering from above:

(1) The water, as it passes through the soil and drains out the bottom of the pot, carries waste products (salts, etc) out of the soil.
(2) As the water saturates the soil and then drains away, it draws air into the soil behind it, providing oxygen for the roots, and preventing anaerobic soil conditions.

However if you took two identical plants in good soil, and watered one from above and one from below (assuming you mean soaking it in a bucket or sink) I don't know that you would see a huge difference. Usually when people start talking about watering from below they are indicating that they have soil problems - that the soil is an impermeable block, or that they are using a hydrophobic soil mix, and the only way to get the soil thoroughly wet is to soak the soil underwater. Certainly it is not practical the moment you start talking about larger trees - you'd spend your entire life removing them from benches and placing them in containers of water and then moving them back - versus just soaking them with a hose.

 

[Dr3z]

The advantages of watering from above:

(1) The water, as it passes through the soil and drains out the bottom of the pot, carries waste products (salts, etc) out of the soil.
(2) As the water saturates the soil and then drains away, it draws air into the soil behind it, providing oxygen for the roots, and preventing anaerobic soil conditions.

However if you took two identical plants in good soil, and watered one from above and one from below (assuming you mean soaking it in a bucket or sink) I don't know that you would see a huge difference. Usually when people start talking about watering from below they are indicating that they have soil problems - that the soil is an impermeable block, or that they are using a hydrophobic soil mix, and the only way to get the soil thoroughly wet is to soak the soil underwater. Certainly it is not practical the moment you start talking about larger trees - you'd spend your entire life removing them from benches and placing them in containers of water and then moving them back - versus just soaking them with a hose.

Ahh this makes a lot of sense actually! Thanks for the help! The tree in question a pomegranate (punica granatum) is doing well getting watered this way (possibly even better) but I do worry about that (as per your point regarding soil permeability). I find it needs water less frequently when I do and worry that could lead to root rot long term. I think it's a symptom of the soil it came with but I'm trying to be patient and give it till next spring before messing with it too much.

@sorce
Thanks for the welcome and your point regarding fertilizer, another piece of the puzzle now fits

 

[sorce]

worry that could lead to root rot long term

Root rot is damn near a myth.

You can probably Repot in summer.

Sorce

 

[Paradox]

The tree in question a pomegranate (punica granatum)

Found this info online about repotting a pomegranate

Repotting. Repot your pomegranate tree when it becomes slightly root bound. The right time to repot is when there are no flowers or fruits on the plant, especially when it starts its growth at the beginning of growing season.

 

[Forsoothe!]

Root rot is damn near a myth.

You can probably Repot in summer.

Sorce

I've only personally seen root rot in two trees. Both of them bought late in the season so I did not repot in my own mix. I do not do major work after late August. Both trees were from well-known bonsaiists of good reputation, but very different cultural situations, both unlike my conditions. Both died over winter and the roots were rotten in both cases. One was in a typical bonsai mix that I couldn't ID, the other in pure kanuma that was a soggy, degraded mass (this tree had been wintered at elevation in Colorado with very dry ambient conditions). I have personally killed many trees in a variety of ways, including too much water in the off season (in the greenhouse), and the only plants that could have died with "root rot" type symptoms were those too wet over winter. In the growing season there is no such thing as too much water for a tree growing in the sun, here in Michigan where we have fairly uniform precipitation year-around. I cannot speak to what happens in wet areas of the world.

The lesson I learn from this is to get the plants I acquire in my mix ASAP, because that's what works for me in my conditions.

 

[Eckhoffw]

I’ve had a few plants with hydrophobic conditions. Dunking worked wonders.
However, I’ve heard that repeated dunks can cause further compaction of the medium, and shouldn’t b done regularly.
Any thoughts on this?

 

[sorce]

roots were rotten

Not to nitpick....

But I consider root rot (the pathogen) and rotten roots 2 different things.

thoughts on

I think you can get it to regain vigour safe enough to Repot before negative effects of the dunking.

Of course....

Aerating the soil helps.

Sorce

 

[Deep Sea Diver]

Practically all my trees are being watered from above as we speak! The Weather Gods in Puget Sound haven’t heard about watering from below. I follow suit in my regular watering. However I keep the trees from crowding and normally water when these have a chance to dry..

At the Museum we see a good deal of donated trees that come in with poor or super compacted soil and also pots with inadequate drainage holes. (We just had to work for a couple hours on a juniper just to carefully dig out most of the compacted soil.) The former is usually because the donator aged up or got sick and could no longer tend to the trees. The latter is often observed on older pots.

Occasionally we see obviously unhealthy trees come in and peak underneath to discover the drain holes mostly clogged.

btw: I’ve had a lot of experience lately drilling older pots (not museum pots), but have been very happy to see that all the pots I received recently from @sorce and Vicki Chamberlain all have really healthy sized drain holes.

Cheers
DSD sends

 

[HorseloverFat]

There are strange pots... and also nearing repot pots.. that I HAVE to dunk.

Most get watered, heftily, from above. If I am confident in the soil mix, I, also, don’t worry about OVER-watering in the “on season”

My answer is:..

BOTH..

Get some’o’dat Forrest Gump rain.

 

[Forsoothe!]

Not to nitpick....

But I consider root rot (the pathogen) and rotten roots 2 different things.

Hah! Nitpicking is my forté. I consider the same. The pathogen(s) is responsible for the resulting appearance and occurs in soil conditions that are constantly soggy. Usually accompanied by a bad smell as the result of dissolved sulfur dioxide gas which is the product of decaying dead plant material normally present in healthy media, which (gas) would escape if not held in the wet solution. The soggy media does not contain the microbes that would consume the dead plant matter and (are part of the process that) produce humus, which incidentally smells nice.

 

[Wires_Guy_wires]

I’ve had a few plants with hydrophobic conditions. Dunking worked wonders.
However, I’ve heard that repeated dunks can cause further compaction of the medium, and shouldn’t b done regularly.
Any thoughts on this?

I think it's a myth. Even under water, gravity still works but it's countered by air inside the particles. When you move a pot from a dunk, water is still drawn out of the bottom. I think watering from the top down is washing gunk to the bottom of the pot more than dunking would. While dunking provides the chance for soil to move sideways, up and down, it's possible that your soil might rearrange to be both more compact as well as less compact depending on how tight it is packed in your pot - can it move or not? Heavier soil particles like granite shouldn't move much but logically they'd compact more due to their weight, lighter particles like pumice and lava rock might actually want to float and move upwards causing decompaction. If you have an homogenous blend of soil, this should cancel out most effects.
The issue I have with dunking is that all my pumice floats out. The goldfish think it's food.

 

[Eckhoffw]

I think it's a myth. Even under water, gravity still works but it's countered by air inside the particles. When you move a pot from a dunk, water is still drawn out of the bottom. I think watering from the top down is washing gunk to the bottom of the pot more than dunking would. While dunking provides the chance for soil to move sideways, up and down, it's possible that your soil might rearrange to be both more compact as well as less compact depending on how tight it is packed in your pot - can it move or not? Heavier soil particles like granite shouldn't move much but logically they'd compact more due to their weight, lighter particles like pumice and lava rock might actually want to float and move upwards causing decompaction. If you have an homogenous blend of soil, this should cancel out most effects.
The issue I have with dunking is that all my pumice floats out. The goldfish think it's food.

Thanks!
Yeah - that makes sense to me.
You have a rain barrel with fishes? I need to get one set up.

 

[Forsoothe!]

I think it's a myth. Even under water, gravity still works but it's countered by air inside the particles. When you move a pot from a dunk, water is still drawn out of the bottom. I think watering from the top down is washing gunk to the bottom of the pot more than dunking would. While dunking provides the chance for soil to move sideways, up and down, it's possible that your soil might rearrange to be both more compact as well as less compact depending on how tight it is packed in your pot - can it move or not? Heavier soil particles like granite shouldn't move much but logically they'd compact more due to their weight, lighter particles like pumice and lava rock might actually want to float and move upwards causing decompaction. If you have an homogenous blend of soil, this should cancel out most effects.
The issue I have with dunking is that all my pumice floats out. The goldfish think it's food.

Thinking out loud, but never having dunked anything, it occurs to me that if you are really chasing air out of the mass you should see a stream of bubbles or foaminess on the surface of the pool. After all, the air has to leave in order for the space to be filled with water. No?

 

[Wires_Guy_wires]

Thinking out loud, but never having dunked anything, it occurs to me that if you are really chasing air out of the mass you should see a stream of bubbles or foaminess on the surface of the pool. After all, the air has to leave in order for the space to be filled with water. No?

There are streams of bubbles sometimes, but those usually originate from air pockets in the soil and not from pores in the particles. The pores are often too small to let water penetrate well, or big enough to let water pass right into them. The smallest pores and middle ground (which do let water in, but the particle itself has to be wet) start floating until the particle itself is saturated.

@Eckhoffw yeah, both a rainbarrel as well as a small pond. Both contain goldfish to combat mosquitos. Not sure if it helps, but they seem healthy and they're growing even though nobody feeds them.
I'm surprised every year that the rainbarrel goldfish survive freezing winters. Don't ask me how, but they just do.

 

[Deep Sea Diver]

I would say its all about density, water flow and interstitial spaces... or its "All a wash!"

However the goldfish knocked me off my word track!

DSD sends