Originally Posted by Jark
My questions are:
How long should I soak it?
Are there any major drawbacks from pre-soaking/rinsing?
I would soak it overnight, carefully pour off the floaters and the stained water, refill, and repeat two more times. (Or as many times as you have patience for, lol.) The only drawback I can think of is that you may loose a considerable volume of the original soil as you discard the floaters. This depends on how much coarse organic material is in the soil. Miracle Grow Organic Choice Potting Mix is especially bad in this regard--if you are using it, expect to loose 1/3 to 1/2 of the original volume.
But this is a small price to pay for fixing all the other problems that come with MGOC.