I would say yes, most likey the rain washed most of it out. I usually move my containers under the eave or the gazebo if rain is coming to avoid fertilizer washout.

Joe

put a plastic mulch cover on them. like the ones used on the earthbox or earthtainer.

This is more of a problem if you use full strength fertilizer every two weeks or so. I prefer to use either a half dose weekly, or a quarter dose twice weekly. I leave my plants out in the rain, and if it rains, I'll give it a half dose the next time I water. I have had much success doing it this way. If we get a long spell of rain, I'll still water with a weak fert anyway. You need very well draining soil to do this though such as the 5-1-1 mix mentioned in other threads.