This is about my Jades and I hope it helps many here! Enjoy and I hope you learn.:-)
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After coming here for a long time, I have realized that any plant susceptible to disease or pest is usually one with a weak root system in the first place.
A plants that is continually repairing its roots due to a PWT is eventually going to die and that is it.

The real key to ensuring an opportunity for your plants to grow to their genetic potential within the limits of OTHER potential limiting factors, is to eliminate all, or at least most of that murderous perched water, and I mean murderous!. Perched water really does kill. It kills the finest roots within hours, and kills progressively larger & larger roots as the length of time it hangs around increases.

I have seen evidence of this every time I get a plant that is potted in a fine mix.

I was getting fungus issues on my extremely rare jades and I was not about to spray them with fungicide or anything until I made sure the roots were doing their job. I was in a rush to fix this. It is common sense that a very HEALTHY plant, one full of vigor is less likely to be susceptible to what I am about to show you.

These plants just started getting brown spots on the most vulnerable leaves, being the most brilliant ones with little chlorophyll, which by nature can be more affected than the greener ones, and the brown was eventually eating away at whole leaves. Take a look. For me it was quite concerning.

All plants that normally have shallow roots when growing in situ do so because air, water, and nutrients are found there in the most favorable ratios.
That is why Bonsai plants do so well in shallow containers in such a gritty mix and jades should do so likewise.
Those same plants, grown in containers in a well-aerated soil will very happily occupy the entire soil mass from top to bottom. Well, these did not because the PWT was killing them beyond 1/4 inch of the top of the mix. No wonder many after pulling their plants out of mixes with fine particles will find very small roots on a very good sized plant. The roots on my plants in just a 4 inch container should have filled these pots by now! Take a look at what I found and I can tell you that these poor plants would have died if I had not saved them. Roots are opportunistic, just as spoken, and though they don't 'seek' water/air/nutrients, they DO grow wherever those conditions are favorable and obviously they were not happy in this crappy mix!

I had to cut off most of the roots off my plants up to almost the stump and that is pretty sad. No wonder they were susceptible to issues, especially on the leaves. I can only pray I caught them in the nick of time. Look how dead they are:-(
I should have planted them right into my gritty mix as soon as I got them knowing the mix is much more forgiving to shorter wet and cooler days. These are picture taken of 3 of my precious jades.

Now that I have cut of all the dead roots, potted them into a gritty mix, and pulled off the brown infected leaves, I pray they will do just fine. Here are after pics taken an hour ago. I hope many here have been helped and can learn from my experience.
I also have' AL/Tapla' to thank, for teaching me all I know to spare any of my plants from near certain death.

Mike

I could never understand that statement. Overwatering that is when often blamed on the person behind the watering can and hardly ever blamed on the mix. Are you saying that I water those plants too often or that this mix is holding moisture far too long?
I have a feeling you might be thinking 'I' am overwatering. Well, just in case, I will explain.

If 'I' was heavy handed with the watering can and watered too often, that is before the mix dried out, then to me that is my fault and I would take full responsibility and called that 'over watering' on 'my' part. I have been guilty of this in the past.

But If use a mix that takes days on end to dry out. practically feels like mud that can not even sit in the rain for fear the mix will stay too wet too long, I call that a crappy mix that does not function well, do its job, and not due to my watering habits. I suppose my fault for using such a mix?
Would one call it "overwatering' if one sticks plants that by nature sit in crevices of rocks, on tree bark with no soil at all, or in sandy desert soils in a swampy area?

Yes, maybe I should of kept them out of the rain and out of that mix when I first acquired them, but I would much prefer a mix that allows them to be rained upon everyday without fear of rot like my others and one that also dries out within a reasonable time and keep them out of swampy mixes.

I check to see how long it takes for a mix now to completely dry out, especially when the weather cools and days grow short, I mean right to the bottom of the pot at that size after an initial watering, and week or more to dry out, especially for jades is much too long and therefore the results you see above and the reason why I transplanted.
I suppose you could overwater in a much more open and porous mix, but chances are highly unlikely, even in rain for days on end.

Why is it that my Bonsai friends can not even use a mix that has so many fine particles, but have to amend their mixes to be much more porous? MG is out of the question.

I think you get my point.

Mike:-)