have you considered cloning?

I am here to preach the sermon of the one seed my friend!

just kidding but if you like growing one variety or  just a few it's economical to grow clones and keep a mother plant. usually I consider myself lucky to get them to teens so when I get one I can take cuts from I do.

as far as what's going on? hard to tell, most of us here a "visual" or use touch and smell to analyze our plant issues 🤔 maybe a few photo's would help

most of my issues are from too much love or I forget to pH or ppm the juice. not a soil man so I start fertigating right away.  in my soil grows, nothing but water. and if it's soil I have to be careful because I like water. More's better right?😄not for seedlings evidently. 

we will certainly help if we can but not sure there isn't much info to work with since it appears from what you've written they should be fine. of course I wouldn't use the jiffy stuff, too often they add in nutes or shit you don't want, but others have used it quite successfully. Me? I would get a nice airy bag of seed starter soil from fox farms and follow the bag. stuff is alright for what it is. you can't always just drop your sprout in some mixes, this is one I have used successfully and I am certain there are others. 

this is all I got, good luck