I never got to use any of the cilantro I planted this year as I was too inexperienced to know that it didn't last long. I looked up, "how and when to harvest cilantro leaves" only to learn that they had already bolted and I was better to sit tight and wait for seeds. Who knew. Tonight I googled, "how and when to harvest cilantro seeds" and learned that how was pull them off, and when was right now.
Cilantro seeds, for those of you that may not know as I did not, are ready as soon as they start to turn brown. That seemed a little abstract to me but when you look closely enough there is a definite lightening of some of the seeds and those lighter ones come off much more easily than the bright pea green seeds.
I am sure I will smell like cilantro for days. But I did get a little bag full, and there is still at least half as much that was not ready to come off. Those stalks I placed in a vase with some water as I had already chopped them down.