Grim Reaper 14
There is an AIC (I can't remember which one) that gives a table of factors to apply to the aircraft's take off & landing distances, to allow for such things as wet grass (which can add 30% to the take-off distance).
This table is also on the back of
Safety Sense 7 - General Aviation - Aeroplane Performance
It is also repeated in LASORS 2002, Pages 487-494
All well worth reading, as it encourages us to consider such things as slope, grass/tarmac, wet/dry, runway length, etc, before committing ourselves to a visit to that airfield.
Have fun with the grass landings
