It might help to know where you're located in Maryland.

I would check with the Dahlia society, as I know they order in bulk for their members to winter over their dahlia roots.

Sorry, I'm in Hyattsville, just outside the northeast border of D.C. So anyplace in the Washington area would be great, but I'll drive if I need to.

How would I find the "Dahlia society"?

Crcurrie, there's a place in Frederick called the Dutch Plant Farm and I get coarse vermiculite from there. I buy it in 20lb bags. But I'd think that most good garden centers should be able to get it easily.

Sorry for being obscure about the Dahlia Society! I have a friend who's very active in the National Capitol Dahlia Society, but he said they order their vermiculite in bulk from a wholesaler in the fall. Sorry for the lack of useful info....I was unable to find it in the garden centers near me. He said he'd ask at their meeting tonight and I'll let you know if I learn anything.

I was in the same situation last year and finally located it at "Virginia Green Grocer." They delivered eight 4 cu ft bags at $18.91 each to my daughter's house in Virginia (I think they didn't deliver in DC where I live) plus $30 delivery. We figured it would cost almost that much to drive to Warrenton to pick them up. I was delighted with their service. Unfortunately, when checking for their website today, I learned that they are no longer allowed to sell agricultural products. What a shame! In the past, when I couldn't locate the coarse vermiculite, I gave in and used the finer grade. The coarse works much better. If you do locate it, please make sure to post the information.

Southern States (just off Rt 301 in Upper Marlboro) carried this a few years ago, tho I don't know if they still do.

Good source for perlite & other bulk garden supplies, whether they still carry it or not.

Steven