You have been luckier with your ipomoeas than I have, Charithea, Well done. I have had problems for the last 2 years. I'll answer your question first and then tell you my woes. The last ipomoea could be either I. tuberosa or I. tuberculata. The former has enormous seeds, even bigger than I. alba. I. tuberculata has similar sized spherical seeds similar to I. tricolor.
This year the problem was a very bad hail storm which smashed nearly all my seedlings within 5 minutes. Not only ipomoeas, I'm afraid, No Coreopsis tinctoria 'Mahogany midget' this year. No Linum grandiflorum rubrum either. Easily rectified with fresh seed next year but very frustrating! 1 I. alba has survived out of 10 germinated seeds, 1 I. hederifolia 'lutea', too. I should count myself lucky - 2 I. tricolor, red have made it through to the summer. And, apart from 1 new seedling (Mina lobata?) that is just emerging, that is it. I. tuberosa took a long time to do anything but did eventually produce long roots. No seed leaves ever appeared and then they rotted. I. tuberculata seeds are still sitting in the pot with no sign of life. Out of 15/20 I. quamoclit, not one survivor. All very disappointing. I still have a few I. alba seeds, so I will try to germinate a couple more and keep a few for next year too. Fingers crossed