And it's reasonable for them to establish some best practices like that. The smaller the pieces -> the larger the surface area -> the more quickly digested. Nothing magical happens when you hit that 6-12" sweet spot, but it is a manageable size to shoot for
The compost masters at UpGarden insist that all green material be chopped into pieces that are 6"-12" long.
And it's reasonable for them to establish some best practices like that. The smaller the pieces -> the larger the surface area -> the more quickly digested. Nothing magical happens when you hit that 6-12" sweet spot, but it is a manageable size to shoot for