Not sure who told you that Happy Frog is bad but, and this is just in my and quite a few others on this site’s observation, Happy Frog is a really good soil. I have heard of some having bugs, but that happens if soil is old or was not stored well.
My current grow, The Force is Strong in this one! was Happy Frog from the start and you can see the results I got ! ! This is the first time I have used Happy Frog and I am sold on it. Never used Strawberry Fields but love the Beatles song of that name.
I am not sure of your source for seeds but it can be a seed problem.
Soil that is too “Hot” can cause all kinds of problems also. The Miracle Grow, in my experience, can cause those type of growing problems. New seedlings do not need any nutrients until they loose their baby leaves on the bottom or later.
Sometimes the plant just gets a bad start for whatever reason and will grow out of it. I have burned several seedlings in the past with different soils but now I believe I have the one I want.
Hope this is what you are looking for. If not I am always around. 
