Does adding Perlite really provide any benefits? I am not so sure

[flexy123]

Pretty much anyone tells you how beneficial it would be to add 20% or 25% Perlite to whatever soil or potting mixes. It's supposed to help drainage, help the roots breathe etc...

I actually don't see that perlite helps drainage, it does exactly the opposite. It keeps and holds water. Those pots where I added perlite into the mix are staying moist a lot longer. I don't consider this good. The longer the moisture is kept in the pot, the higher the chance that it promotes mold/root rot etc.

Looking at it that way I don't actually see any benefit in adding perlite to soil, except maybe for "lightening" a soil mix that is too "hot", say for seedlings. I added another 20% of perlite to "Canna Terra Pro" soil I had which already has like 10% or so in it, but now I actually regret it and think I shouldn't have done this...

 

[OldMedUser]

Perlite doesn't actually hold water. I can wick it up on it's surface but the stuff floats so it's not absorbing the water. Vermiculite, expanded mica, holds lots of water tho. I always add about 25% perlite to the older ProMix but got the HP and it has lots of perlite in it already.

If anything my pots dry out faster with it and I wouldn't grow without it.

L8r

 

[Richard Richardson]

I usually add lots of perlite, but recently I had to repot hastily and only used peat and a sprinkle of great white.

3 weeks later, the plants are doing fine, drainage is good and the peat is drying nicely, almost daily.

I think perlite helps more against compaction of the growing medium, than drainage in general.

 

[Stealthboat]

When I up'ed the ratio of perlite to Promix during my last grow transition, the amount of water changed. With less perlite, I was giving it 1 and a 1/3rd gallon with 15-20% run off. With more perlite, I now use 4/5ths of a gallon with 15% run off. This equates to a reduction of 20/15 of a gallon down to 12/15 of a gallon, a significant reduction. And nothing changed expect for I up'ed the ratio of perlite by 10%. I'm assuming less Promix = less absorption so that is why this happened, hope it helps you somehow