I would use new soil or at least mix the old in with new soil.

The question about reusing old soil seems to always avoid mention of what the old soil was made of. The organic portion of the old soil, you should assume, was consumed in the growing of the last plants. Almost all the ready made container soils available at the garden centers, are NOT suitable for reuse, even with the addition of fresh organic matter, and should be added to the garden, perhaps in constructing a berm. Al

Thanks. Will use new potting soil. The old is also commercial soil.

And now I will look up the vocabulary word of the day: bern.

I have had a similar question about Al's mixes. I plan to reuse some 5-1-1 and some gritty. I will replace the fertilizer but what about replacing lime or gypsum?
I know, Al would not want it called "Al's" mix if it was reused but I am cheap and I estimate I made about a yard of this stuff last year and do not feel ready to throw it out and start over yet.
In my defense, the pine bark fines I used last year in the 5-1-1 were fairly fresh (not composted)and a bit on the big side. I suspect they may be a bit more ideal after aging a year.

Kyle

The Ca fraction of the lime isn't very soluble. In comparison, the Mg fraction is about 125X more soluble than the Ca fraction. For that reason, an occasional application of Epsom salts is a good hedge if you're gong into the second year using the same soil.

Al

Thanks Al-
And I wasn't even scolded for being cheap.
Some follow up if you don't mind-
I have some containers that had hydrated lime rather than dolomite (mostly for my tomatoes). Would this be more soluble and need replacing?
What about the mix with gypsum rather than lime?

Kyle

"I have some containers that had hydrated lime rather than dolomite (mostly for my tomatoes). Would this be more soluble and need replacing?" It's a LITTLE more soluble than dolomitic lime, but I don't think you'd need to replace it in the second year - especially if you're using a fertilizer that contains Ca.

"What about the mix with gypsum rather than lime?" Gypsum is quite a bit more soluble than dolomitic lime. About the only thing I use it in is the gritty mix, and I've never had any indication of a Ca deficiency in growth cycles subsequent to the first in the soil. Again, probably especially so if using a fertilizer that has Ca.

Al