Iown only woods too, but for the past two years I've planted a food plot on a fenceline. There is a pretty good canopy of trees but the fencerow gets the ground enough sunlight. I mow it down with a regular household mower and till it with a tiller.
I've had great results so far. I also planted a bowhunting plot on my Grandpa's property and it looked like a golf course.
Here are some pics. Both of mine were maybe 40 yards from my stand tree at the furthest...of course I was bowhunting...but both brought in deer...
You can see the corn feeder, but all the area directly in front of the camera (shaded) is where I plant my food plot at our house.
This is my Grandpa's plot. It's in a wooded area too but the pic was taken at night-time. You can see how well it came up though...