Secret to starting Trinidad Scorpion seeds?

Fold a paper towel a few times, dampen it, press as much water out as you can, put the seeds on the paper, fold them into it, put the paper in a ziplock bag, and put the bad on something that outputs low heat. Like a fridge. Give them 3-4 days and take a peek. Should have a tap root by then. Could take longer though. Avoid direct sunlight at first.

Your soil may be too cool.

What soil and temperatures are you using in your hothouse? Varieties like the Trinidad need specific temperatures that are typically higher than those needed for other peppers.