I'm using objects as particles but the objects have hair. Why is the hair is all going sideways? I made some wheat, complete with the little hairs.  I've set up a particle system to use my wheat reference and the result is pretty good at first glance.

However, if I turn off phase randomization it pretty quickly becomes apparent that the hair system used on my object is all biased in one direction.


I haven't used any Tangent or Object Aligned particle velocity and my scene doesn't contain Wind.
This is an object that I approved of wholeheartedly before I prepped it for use within a particle system.  (R X -90 and Apply Rotation)
The answer has two parts.  First was that I had used a (hilariously) small amount of Gravity for growing the hair for just a touch of realism.  It is truncated in the UI to three decimal places.

Secondly, when I rotated and applied the rotation, my object was ready to be used as a particle, but it was on its side in scene space, and the hair system on the object still respected gravity in scene space.  In other words, the hair now understood gravity to be something that pulled to the side, in a sense.
But afterwards you can freely rotate an object, and as long as you don't apply the rotation the change won't be reflected in instanced objects.
So I simply rotated my reference object back 90 degrees on the X axis such that it was reaching for the sun like a good wheaty, and everything is fine. 

Reintroducing phase randomization.