If by Sweet Pea Vines you mean what I would just call Sweet Peas, they are a cool season flower and I would never use a heating mat with them. In fact I would just generally plant them directly outside. I've only grown the Black Eyed Susan vines once a long time ago, but from reading on the web, they usually take 10-14 days to germinate (I might use a mat on them).

When you say "fuzz on the pellets" do you mean the soil or on the seeds themselves. If the seeds themselves are moldy usually they're dead/done. If it's just the soil, I might try (gently) to manually remove the fuzz.

Anything that has germinated needs to be removed from under the cover ASAP and moved to the lights. The rest can remain.

But if you have mold or fungus growing on the soil (there is a FAQ here about it) surface then yes it is too wet in there. But that as well as reduced germination rates are 2 of the common problems with the pellets.

As to needing light, nothing on your list requires light. While it may help some the majority of your issues will be peat pellet related ones, not light.

Dave

Thanks for your comments! Still nothing from the salmon shades nor the mrs collier sp. However, the Spanish eyes are sprouting like crazy and I have a handful more of the others. Not sure if it is a too wet problem or what. I pull them out and put them under lights as soon as they come up. I'm just wondering how long to wait on them to germinate. One month total? Longer?

Thanks again!

Another question - I was planning to plant my seedlings around an arbour, soon. I had read that they should be spaced about 6" minimum apart, but was recently told by a family friend to space them no more than 1-2" apart, which seems very close. I am also wondering if I will need to provide twine or something for them to climb on the arbour (it has latticework, but I wasn't sure if they could grip lattice).

Thanks again!

I don't know the spacing on Black-eyed Susan vines (did your seed packet have spacing information?). Sweet peas I believe can go as close as 2 inches.

As to your arbor/trellis, you need to read about the Black-eyed Susan vines as it depends on their climbing method. Sweet peas have fine tendril at the tips of their leaves and will need something like twine to climb as lattice is too bulky. (General rule of thumb if the plant twines around, or it has aerial roots, it could climb a lattice. If it uses tendrils something finer is called for.)

I grow Thunbergia every year, and Sweet Peas every few years. Sweet Peas don't transplant very well, but are easy to start by planting them directly in the soil. They'll germinate in cold soil or warm soil. I usually plant them in October here in northern California, when the temperatures are pretty warm, and they seem to take a few weeks to show up (trying to remember). One year, though, I planted them late, and we had some really cold temperatures, and up they popped! So maybe colder temperatures hasten germination. If I had paid more attention I would likely have more specific information. Anyway, I plant Sweet Peas about 2-3 inches apart in soil enriched with plenty of compost. I always cover these seeds with enough soil to block out light, not because light is an issue, but so that the large seedlings have more of an anchor.

Thunbergia seeds are generally pretty speedy germinators when given heat, much slower to germinate (can take a month sometimes) at lower temperatures. I would plant these more like 6" apart than closer because eventually they will branch out. Once they get going they can be pretty aggressive, but it takes a little while for them to get their rhythm, so to speak. I've never grown them on a lattice, but I plant them with cukes growing on long tomato trellises, and they twine around the trellis and the cucumber plants very nicely. I've also had some pop up in odd places where there is no support, and they are full enough to look nice sprawling over the ground. This is another seed that I cover with enough soil to block out the light for the same reason I do the Sweet Pea seeds.

I've don't believe that sweet peas need darkness to germinate. Just keep them warm and moist. Seven days isn't a long enough time period to start worrying. Could be slow; might need over two weeks.
Begonia seeds need light to sprout and Alliums need darkness in order to germinate. But I only know that because I plant these.