Re: Potted daff's.
I agree with Pixie on most of this, Carol.
Some people say feed the bulbs just for 6 weeks after flowering (tomorite will do), to make sure all the supplies they have used up are put back into the bulb ready for next years blooms.
The most important thing is though, only remove the dead flower heads N
NEVER the leaves as they send goodness back down to the bulbs.
Only remove the leaves after about 6 weeks or so, or whenever every part of the leaf has turned brown and died, then its safe to cut them off.