hudsonvalley, you can cut your daffs as soon as the bud is fat and showing color or you can cut them when they are fully open. I find the best way to harvest them is to hold the stem as far down as I can get my fingers and give it a good tug. Usually, the stem breaks down below ground level and you will see a whitish area at the bottom of the stem, sometimes it will break further up, either is fine. You should then cut the white area off and put the daffs into clean water. Daffodils exude a gooey sap and should not be conditioned with other flowers until they have been in their own water for at least an hour, I like to keep them separated for at least three hours and then you can mix them with other flowers, you will notice that the bottom of the stems might have split, just cut above the split before arranging them. The gooey sap is nasty for other flowers and will prevent them from taking up water. Picking your daffs will not kill the bulb, just let the leaves complete their cycle through yellowing and cut them off and you will have daffs again next year, probably more of them. Enjoy. Kat