top dressing

Here in the Pacific northwest, we have lots of cool wet weather. Normally, i'd top dress with a smaller sized Akadama and call it good. In the back of my mind, I keep wondering if i went to a black volcanic top dressing
if that might create more warmth with out limited sunlight times in spring and fall. july and August worry me tho, as that's when we get our strong dose of sun and would that be too much then. Kind of a ramble, I know, but would appreciate any input you might have based on your experience.

Interesting question. I don't think it would make much difference, but it would be interesting to experiment with two or more pots one with the black stone and one Akadama, get a soil thermometer and record reading.
You could even use empty pots.

Hi Dick,
You could use the black volcanic top dressing, then take it off during your hot months and use something else such as Turface...
Todd

Im newly into potting up trees (just been field growing for the last 7 years) and have several questions about this topic. I see a lot of people top dress with akadama, I thought it was just for looks prior to a show and to make people think you use pure akadama (Ive been told judges look poorly at trees if they are not in traditional soil mixes). My other question is- if you top dress with one material wouldnt it make it more difficult to know the moisture content in the deeper portion of the pot? My theory was to make the soil as homogenous as possible so that by looking at the surface I could more easily tell whats going on deeper in the pot. Ive been told all those early bonsai books with different sized particles in multiple layers within the pot is really not needed.

I see a lot of people top dress with akadama, I thought it was just for looks prior to a show and to make people think you use pure akadama (Ive been told judges look poorly at trees if they are not in traditional soil mixes).

I have never thought or heard this in Florida.

My other question is- if you top dress with one material wouldnt it make it more difficult to know the moisture content in the deeper portion of the pot?

But if you use a meat skewer or other probe, it wouldn't make any difference.

My theory was to make the soil as homogenous as possible so that by looking at the surface I could more easily tell whats going on deeper in the pot.

Maybe, but this is risky.

Ive been told all those early bonsai books with different sized particles in multiple layers within the pot is really not needed.

I think we have all agreed that is not required.