Did you just distribute it on top of the bed, or rake/till/otherwise mix it in? If (hopefully) it is just on top, how about simply sweeping it off? Or getting out the ShopVac?

I sure don't know enough soil chemistry to suggest any ash-countering additive! Heck, I didn't know that ash was alkaline.

But... I am going to guess that if your soil was acidic to begin with, you're probably going to be OK. The soil is such a large pH buffer that acute modifications like this usually don't produce much lasting change. However, if the soil was alkaline to begin with and you had to fight to lower the pH, you'd probably have a bigger problem.

I'd suggest checking in with folks in the soil forum... some pretty smart buggers over there.

My understanding is that even a small amount of wood ash causes a large shift in soil pH. Therefore I'd think you'd be best to remove as much of the ash-enriched soil layer as you can and replace it with more neutral or even acidic soil. Amending with peat will help some toward bringing the pH back down, but peat isn't nearly equivalent to an equal volume of wood ash in terms of its ability to change pH. Good luck!

cranebill