Last summer, I started two batches of Clivia seeds from my 'Aztec Gold' plant. One batch, I put into a sealed glass jar and left them to sprout. The second batch, I just potted up in small pots full of soil like regular plants.
In the beginning, the glass jar seedlings appeared to have a substantial advantage. Not all of them germinated (I got maybe 75% doing something1), but those that did grew well. Only about 40% of the ones in pots of soil did anything, so I concluded that the glass jar was the way to go in the future, should I be fortunate enough to get Clivias blooming again.
There was one significant flaw with the glass jar plan, though, which was that I assumed that the seedlings were fine there, well after it became apparent that they were not. And, being lazy, and having many other plants to deal with, I left them in there anyway.
So then one day, I happened to glance at the jar and saw that some of the leaves were yellowing from the bottom up, and took that as a sign that I should do something quickly. Unscrewed the lid, and then spent about half an hour trying not to throw up. Seriously. It was that bad. Not that rotting vegetation ever smells like roses (not even rotting roses), but this was actually worse than Dracaena marginata with Erwinia rot, which had previously been my benchmark for unpleasant rotten-vegetation smells.2
Not wanting to give up on the two seedlings in the jar that seemed like they might still be alive, I held my breath, reached in, yanked them out, quickly screwed the lid back on, ran out of the room, took a breath, and then ran back in and potted them up in soil as fast as I could.
Alas, 'twas too late. Not only did a trace of the smell linger on the seedlings after they were potted up, but they died anyway, by the next day. So the glass jar approach ultimately resulted in no seedlings, a 0% success rate.
The seeds potted into soil lived in the kitchen all winter, in a cold south-facing window. I had them in trays along with some Salvia elegans cuttings I was rooting, which needed to be watered pretty often during the winter, so the Clivias never got watered directly, but they had chances occasionally to pull water up from the tray. I started five seeds. Two germinated pretty early and grew a leaf apiece; the other three slowly hollowed out and died. Around March, the two survivors started to make new leaves, so the overall success rate there was 40%.
So. Yeah. Kind of a disappointment overall; I had hoped to have a lot more seedlings to play with than just the two. But we'll call it a learning experience -- no more glass jars! -- and move on. Maybe next year it'll work better.
2 The Dracaena / Erwinia combination had a sharp ammonia note to it that wasn't so much gross (though it was gross) as it was painful. I mean, there was rotting plant smell in there too, but the ammonia smell was what was most memorable. Rotted Clivias, on the other hand, have a much richer, more complicated bouquet, with a dominant note of sickly-sweet. Not only worse than the Dracaena, but worse than anything else I have ever smelled in my life. Smelled like if you were standing right next to Satan as he visited the part of the Hell dump where they put all the rotten fruit, and one or both of you had a suppurating skin infection, and he'd just farted.