Drainage layer on Top?

[biomanz]

I'm just going over this thread on soil physics and seems that drainage layers on the bottom of a pot is actually counterintuitive and "shrinks" the total air pockets in the pot. Question is, what about a drainage layer on the top of the pot? Since the saturation layer would still be at the bottom of the pot, it shouldn't make a big difference would it? Besides the effect of moving from large to small media.

I used a mostly organic soil mix for 2/3 of a nursery pot before I ran out while repotting a plant, and decided to use some bigger grain mix to fill the rest, which also cover the plant's roots. Should I dig it up again and replace the top third to make it uniform?

 

[rockm]

Either way, on top or on the bottom you have the same issue--different soil consistencies. Interaction between them will always be a problem--for instance, the top coarser layer will drain more quickly than the underlying finer particled layer, resulting in a perched water table in the middle of the pot. Roots which should be evenly distributed thoughout the pot, will have issues crossing the boundaries between two different soil layers. Additionally since the top layer will mostly dry out before the lower finer layer, surface roots might be in danger of drying out.

Uniform soil mix is the way to go...

Repotting your tree at this point might be a problem if it was done more than a couple of days ago, as you risk damaging newly developing roots.

 

[biomanz]

Either way, on top or on the bottom you have the same issue--different soil consistencies. Interaction between them will always be a problem--for instance, the top coarser layer will drain more quickly than the underlying finer particled layer, resulting in a perched water table in the middle of the pot. Roots which should be evenly distributed thoughout the pot, will have issues crossing the boundaries between two different soil layers. Additionally since the top layer will mostly dry out before the lower finer layer, surface roots might be in danger of drying out.

Uniform soil mix is the way to go...

Repotting your tree at this point might be a problem if it was done more than a couple of days ago, as you risk damaging newly developing roots.

Ahh I was assuming the perched water table would stay on the bottom. I only repotted it yesterday, so think I'll just take it out again and mix the whole pot evenly.