Since tuberous begoinias are shade plants, how much light sholuld be
provided to seedlings?

If you mean indoors, you could never provide enough sunlight, direct or
otherwise to damage seedlings. Only outdoors could the sun do much harm.
Indoors right now the sun is still way too low in the sky to do damage, so if
you mean a sunny window, that's fine. If you mean fluorescent tubes, at least
two, no more than two inches above the foliage so the stems don't stretch.

Thanks, Victoria; that's exactly what I wanted to know.

vince norris