In reply to chutch:
I was there mid April last year, and Grande Grotta was absolutely dripping. A few people were still trying to climb it, but really shouldn't have been as a dripping tufa is when it's at its weakest from what I understand.
And in I think it was Ghost Kitchen, someone got hit by a big tufa that got ripped off and it broke their collar bone. And I think there was one more story of someone getting hit by a tufa while I was there.
Grande Grotta had stopped dripping by the beginning of May, though.
I think March would mean most tufa climbing is out, even the less steep stuff.
Still plenty of face climbing to do on the island though. I don't even like tufa climbing, and I still really enjoy Kaly.
If you really enjoy the tufas, and want the lowest risk of accidents involving tufas, just go in October when they've had all summer to dry out.