In article idz5i.5515$Ud7.3971@trnddc08,
"Grave Yard Guy" wrote:

"jimnginger" wrote in message
ups.com...
I HAVE 50 OR SO POTS FROM LARGE TO SMALL ALL FILLED WITH COMMERCIAL
POTTING MIX (SUPERSOIL OR MIRACLE GROW) THAT IS A MIXTURE OF FOREST
PRODUCTS, SAND, PERLITE, FERTILIZER, ETC. . AND I DON'T WANT TO JUST
START SHOVELING UNKNOWN CRAP INTO MY POTS. AT THE SAME TIME I CANNOT
AFFORD TO DUMP THE POTS COMPLETELY OUT BETWEEN EVERY PLANTING AND
START WITH FRESH SMALL HOME DEPOT BAGS OF CONTAINER SOIL.

I'm assuming you are aware that you are running the risk of disease and
fungus by reusing the soil year after year?

That said, there are a couple possibilities. One would be to add 1 part
mushroom manure, $3.49 per 40 lb (H. D. and Lowes), to 3 or 4 parts of your
old potting mixture. OR mix equal parts of mushroom manure and peat moss,
$4.99 per 2 cubic ft. bundle, and add this mixture to your old potting mix
at 1 part to 2 or 3 parts of the old mix. The measurements don't have to be
exact. Keep in mind that the peat is going to retain moisture. I over did it
with peat one year and killed off some potted plants that needed better
drainage.

"She was not quite what you would call refined.
She was not quite what you would call unrefined.
She was the kind of person that keeps a parrot."
-Mark Twain

So what you are losing, except for some sand during draining, is the
organic stuff as it decomposes back into CO2 & H2O. As Grave Yard Guy
said, you need to mix in some compost and manure into your depleted
potting soil. Small pots could be dumped into buckets for blending and
homogenizing of the soil.

- Bill
Coloribus gustibus non disputatum (mostly)