Miracid will do it. I think pine needles and coffee grounds might be acidic too.

First, identify the problem. Buckeyes aren't particularly picky when it comes to pH. In other words, I grow them. What they do seem to need is plenty of water. So instead of trying to acidify the soil, I'd try to add organic matter to make it more water retentive. A fairly thick layer of mulch should do it.

Penny-use that worm compost!!!

If you can get access to distilled water (know someone who has a dehumidifier?) use that to water with. Distilled water tends to be quite acidic (pH 5 or less) because of the co2 that gets dissolved into it during dehumidification.

Any compost/detritis from under conifers is usually also somewhat acidic.

-Rosalinda

Thank you everyone. Sorry I didn't respond sooner but I was out of town and still playing catch up with my own forum, garden work etc.

I am going to send of a couple of soil samples and I do plan on amending the soil so that it will hold more moisture. Right now I think it is probably draining and drying way too fast because my penstemonds and agastaches do great in that area.

Thanks Kathy, I wondered if I should add some of the worm castings. I will definitely add that as soon as I can get all the weeds out that took over while we were away. I have also saved some mulch to top dress once I get the soil amended.

Penny