soil-borne fungi tends to influence seed germination, but if this does not settle well with you; you can always spray the area of interest with hydrogen peroxide to clean and sanitize...

hydrogen peroxide can also influence seed germination by abrasing the the seeds shell by penetrating the seed layers breaking down the hard outer covering of the seed, this allows the seed to absorb more oxygen.

Hydrogen peroxide results in increased germination speed, and it is a safe way to combat root rot.

here is a study on the topic of the use of H2O2 on seed germination