I did a big trade last fall and now that I've been planting the seeds I received it's become obvious that there is a problem. Zero germination!! And next to pots with seeds from other sources that are doing fine.
Only know for sure about what I already tried, but with limited space in the veggie garden I don't want to waste any of it on more seed from that trader. So looking to replace: spinach, leaf lettuce, sweet red peppers, hardy lavender, eggplant, lima beans, and esp melons.
All the seed from that trader has been removed from my trade list, so don't worry about getting any in exchange.

Here is a link that might be useful: My Trade Page