Muay Thai Auto re-vegged at week 10

First time that I bought seeds from Flash Seeds. Communication and shipping was prompt and friendly. Payment was practical and secure. There was no mail tracking but from the communications and reputation, I completely trust Stich @ Flash Seeds. Again, I am not motivated to buy for mystery freebies. I want what I am willing to pay for. Dealing with Flash Seeds is straight forward and easy. Good impression from the seeds. Muay Thai is a sativa but seeds were big. Germination was fast and was 100% on four seeds. Roots buds popped in the glass after one night soaking in water with hydrogen peroxide. I never had much luck with sativa seeds. So, I kept the seeds in the cotton pads until the roots were a little longer. This took 48 hours. And roots were around 10 mm long. Soil in the cup was 50% worm casting with 50% of my old soil mix. Total composition: 50% worm casting, 25% coconut husk, 15% pumice, and 10% of garden soil. Then I got into trouble. Three seedlings damped off. And the survivor look week. I kick myself for using old soil instead of starting with sterilized peat moss.