Damping off wipes out more regular seedlings than bad genetics ever does. Starting twenty seeds in a crowded tray with poor airflow is a perfect setup for the fungus, and losing a third of a pack at the stem base in week one is a miserable way to begin a hunt. Prevention steps, from sterilizing trays to running a small fan and not overwatering, are run through on https://breederregularseeds.com (https://breederregularseeds.com). Spacing seedlings a little further apart costs nothing and has fixed the problem for me entirely.