Sprouting Ipomoea purga and kin

[Leo]

I have Ipomoea purga from SX 480, courtesy of Robert Lauf. I don't see him in the members list for this Forum so I'll post this to the E-mail list as well.

My usual practice with Ipomoea seeds is to soak until they swell, then plant. With the annuals this is usually overnight. With the others I change the water daily. But it's been well over a week and the two I. purga I've been soaking are doing nothing. These come from very dry environments in habitat.

Have others sprouted these? Should I continue soaking or just put them in the ground? Should I scarify them?

[EZielinski]

Leo posted to the PBS e mail group, too.  Robert (who supplied the seed to the SX) and I responded.  Here are the messages.

from Robert
You need to chip the seed coat.  I use a nail clipper and just nip off a tiny piece of the coat, maybe 1 mm or less so the underlying white endosperm is showing.  After you have made a chink in the armor, soaking overnight is usually enough to cause the entire seed coat to crackle.  I then sow in moist promix and they eventually emerge as two gigantic square cotyledons.  Here they aren't winter hardy, so I start in early spring in the greenhouse and plant them out in late April.

from Eugene
I agree with Robert.  I used a small file (rasp) to file a notch in the seed (three seeds, actually).  The seed coat is pretty thick.  I didn't soak them, just planted them in a pot of Pro-Mix type soil and all three germinated in less than a week.
Thank you, Robert, for supplying these seeds.

[Leo]

Thank you both. I filed the pointed end away from the hilum and put them into water. They are swelling.