Record Storage Problem

Are you seeing mold or foxing? Foxing is spotty paper degradation due to acid in wood pulp products. It is less influenced humidity than mold. But mold is a biological-fungal issue highly dependent upon water/humidity. I have trouble seeing how plastic in low SD humidity can induce mold growth. However, I can see how acid in wood pulp of outer sleeve, particularly if inner sleeves is also paper, generates foxing over time.

Hmm, I have a collection of that I have put into outer sleeves in the 1990's in Tucson. Then I have moved to the Pacific Northwest about twenty years ago. I have never seen any evidence of mold or any other problem. 

I live in the Pacific Northwest and I have never even heard of properly stored records developing mold, regardless of whether they had a sleeve.

I'm thinking that whoever told you that the collection was "always, ALWAYS. . . .  under air conditioning." might be stretching the truth.

Mold needs moisture.

Interesting feedback.  I was first schooled on the problem while a student at the University of Washington.  I bought all my records at Standard Record & HiFi, whose owner, Mrs. Smith, was quite firm in advising all clients to do a few things with our new precious records: 1. Take the cellophane cover off the jacket 2. Clean the record (in those days we used a Parastat, or later a new fangled thing Discwasher) and 3. Throw away the paper sleeve and use a poly sleeve.  Mold was a potential problem and the reason for ditching the cellophane covers.  I worked at a HiFi store all through college and saw a lot more records than otherwise might have been the case.  Through personal observation mold on vinyl was a thing and it seemed always to be associated with records being kept in plastic wrapped jackets.  After graduation I moved to San Diego, another stint in the HiFi business, more records, more similar observations.  That all ended in 1978.  Last month I got involved with a large ~8,000 collection.  The records are mostly jacketed in plastic, inner sleeves are mostly paper, they are under AC and at a guess about 60%, plus or minus,have mold on the vinyl.  It takes two full cycles on the VPI to get it off.  And of course it is still on the labels and on the jacket.  It is a PITA.  If you don't have this problem don't let this concern you, it is a heads up to keep people from having to deal with anything like this.

I guess I just never had a problem because I always removed the plastic.

However, I always removed the plastic because I was told that the plastic could shrink if it got hot and it might warp the record.  No mention of mold, hence my response.

Thanks, good to know.

The three record stores in Memphis have all of their used albums in plastic outer sleeves

I have been collecting records for over 50 years now.  I have thousands of LPs that have ALWAYS been in outer plastic sleeves.  I have always lived in the Rocky Mountain region and have NEVER seen or encountered this issue?

I even just went through a few in my collection at random to check and they are as clean as when I bought them...

My collection, ask one point was 4,200 or so, has always been in SEALED outer sleeves (the resealing type).  Not a hint of mold.  They have been in every floor of the house, without issue.

Even the LPs that I gave away and sat in an unconditioned room for a few weeks were unaffected.

I hope that helps.

P.S. I am currently in the S.E. US, where it is hot and steamy for 6 months of the year.

I'm in the St. Louis area (i.e. high humidity in summer months). My collection of some 5000 LPs – acquired over the last 50 years to now – is mostly (not box sets) wrapped in Sleeve City 5 mil sleeves, and there is no evidence of mold anywhere. In fact, recently I went through it all to catalog in Discogs. I pulled many discs out that haven't been played in ages (decades) to check runouts, etc for the proper Discogs entries. No sign of mold at all. 

My records are all stored on Ikea Kallax shelves in HVAC controlled rooms. I'm not really worried about.