ouch, looks like pH or maybe a heat problem. next time try to pop the seeds in one of those 2 dollar clone boxes from walmart(its an easier setup to manage so they dont dry out when theyre young), they like humidity until the second node, then take em out and put them in a good place.
we need to know your setup if you want to avoid this, like what are your lights, temp. in the room, nutes(if you used any which i hope you didnt), soil pH, how often you water and why you decide to water, and anything else you mightve done that nature wouldnt have done.
but use rainwater and test the pH meticulously, itll jump to 7.0 randomly. rainwater should work for 3 weeks, dont use water unless its been out for 3 days in sunlight preferably, some smaller plants cant handle the chlorine in our tap water.
but anyway shes done, next time get some black cow and fox farms, maybe some leaves since its getting into fall and you have plenty to get rid of. put all of this in compost and use the black cow to grow the seedling if its not composted by the time you plant another seed. also, dont use nutes