Harder to not spalt wood in NJ
Depending on where you live, it may actually be more difficult to keep wood from spalting than to have it spalt. I know that if I don't turn it all right away, I'll have spalting by the time I get to it...
What's my secret?
Well, I think it has something to do with how I work in prep and what I cut. I have a specific area that I cut wood into shape in. The area is littered with decaying wood shavings, and it's not uncommon to have mushrooms sprouting. If I was to guess, it probably has had dozens of feet of shavings on it over time, each introducing some decaying matter. It is fertile ground.
To spalt wood, all I have to do is leave it on the ground in this area. Like others have mention, turning your logs is a good idea to even it out. When it gets spalted enough, I take it off the ground and cut off the cracked ends and then into blocks that I seal with Anchorseal. Everything is larger than I need, and finishes however it finishes. I don't sweat the size, since it is free wood (all that I turn...)
S