Look at the edges. the grain will be //// or \\\\ and very, very seldom ====.
You can also tell by looking at the "cathederals" (arches) formed by the intersection of the growth rings with the surface. >>> is going to look /// from side while <<< is \\\ from side.
Some wood have terrible grain, may start <<< and change to >>>. Makes it hard to run thru planer because you want to feed \\\ end in first so cutters are crossing grain and not digging in (prevents chip out).
Run your hand along the wood. One direction should feel smoother than the other direction. If you don't feel a difference, the feed direction shouldn't matter.
If you do feel a difference, hand plane in the smooth direction.
Does someone know how that would translate into feed direction for a planer?
Wiskers towards the back. Smooth direction feeling end in first.
Your hand plane direction, the knife is going the same direction as the knives in a planer (assumeing the planner knives are on top).
Or to try Mad Marks method: ))))))= knives
Board = \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ >>> = direction of feed
In any event, if you get it wrong, you'll know pretty damn quick, cause your face will be like this :-(
My face often looks like that because I run into boards that do this: \\\\/////*\/\/\/\///#\\//////\\\\\\
And that's why I bought a drum sander. But it was a real PITA!:'(
So it doesn't live here anymore.:D
So by now you can see Sonny has found the emoticons and is becomming a PITA with them as well. :P