I store all my seed in the refrigerator in small glass vials. I have great
success germinating seed stored in this manor.
As far as germinating D. capensis, you don't need to cover them at all.
They will pop right up and take over any pot they land in. I think it is
quite a nice plant, so I don't mind that it is weedy.
Let me know if you have any more questions......
Take care & keep on growing,
-Tom- & Krissy