Experimenting with exposure (long) - White Mushroom

Experimenting with exposure (long) - White Mushroom, originally uploaded by Rusty Marvin (having some Strobist fun).

LR-15239 - More Mushrooms, rather than strobist thought I would have a go at a slightly longer exposure, one for me and secondly for an assignment. The remit shot in low light without using a flash poor light under a tree and away from the sun. Experiment with a long exposure Where does that start? Anything above 1 or is the expectation to be between 15-30 seconds for a night time shot ro something with a ND10.

Exposure: 13 seconds
Aperture: f/22.0
ISO Speed: 200 - thought I might get away with 200, nearly but not quite, wish I had done with the strobist now :(
Flash: Off, Did not fire
Lens Model: EF-S15-85mm f/3.5-5.6 IS USM

Scavenger Challenge
19. Take a shot in low light without using a flash. Experiment with a long exposure. (Russ)