I've read that also about the wood ash leaching quickly and not being a long-term pH influence, but being potent in the short-term. True that...
Good idea on testing runoff pH before using! I'll be doing that.

I want to try the wood ash more for the micronutrients than anything else. The reasoning is roughly this:

A piece of wood contains all the minerals necessary for sustaining plant life. The existence of that piece of wood pretty much proves that. Burning the wood completely removes H and O as water vapor, drives off some carbon as carbon dioxide and what's left is practically every element (less C,H and O)that was needed by that piece of wood to become a piece of wood.

Sounds like a good source of micronute to me...as long as I don't scald my plants and make them squeal like pigs! (Wood ash and boiling water - old time pig scalding recipe)
SecretSquirrel Reviewed by SecretSquirrel on . My soil recipe...comments? I had low nitrogen issues and pH flux during flowering in my last closet soil grow. During my next grow I want to buffer pH effectively and provide as much available nutrient as possible in the soil while minimizing the amount of "chemical" additives needed throughout the grow. Here is the recipe for my next soil grow. I appreciate anyone's comments and observations..... SecretSquirrel SoilMix 4 gal compost (roughly 75% plant / 25% manure) 4 gal perlite 3 gal sphagnum moss 1 gal Rating: 5