I understand that seeds can "drown. Any I soak I soak for three to five days changing the water daily. Size is the determinant of duration, that and perceived changes in the seeds themselves.
I think if one soaks any seeds too long one can destroy the seeds. I have not experienced that with Iris seads, but I did indeed experience it with Vigna caracalla this spring. Seed scarified and soaked five days were dead; seed scarified and soaked 24 hours until hydrated were fine. All seeds from same original plant and the same growth season.
I soak to hydrate the seed, not to "leach chemical inhibitors." Any seeds with such alleged inhibitors grown get them leached out through exposure to cold and weather in pots on the back deck. Germination rate is satisfactory, overall, regardless of type, and better than some folks who engage in arcane rituals. I'm not convinced we understand these "inhibitors" as well as we think we do. I sispect that Iris seeds of some sorts can tolerate an enormous amount of abuse and are germinating not because of the treatment they have received, but in spite of it. Just saying.
I would expect that the seeds of water irises would be more tolerant of longer soaks than those of dry land irises, but then there would really be no good reason to soak those, beyond hydration. They respond to the combination of water, and light. I never expect any seed to have any absolute requirement for germination which it would not have gotten naturally at its original habitat. That said, people may wish to speed things along for one reason or another. I figure in soaking I may speed things along by a few days, get them off to a good start. I do not soak seeds I intend to place outside if temperatures outside are already low. I think a sudden hydration followed by hard freeze is not such a good thing.
I soak my seeds in small pimento jars. I would never soak in any sealed container. I use tap water, at room temperature. I never have tried a quick dose of boiling water, although I understand that has been done for oncos. Who? Maybe Dykes, I forget.
Germinating here this week from SIGNA seed: I. prismatica alba, I. lutescens, I. tuberosa.
Cordially,
AMW
