I just purchase what ever generic starter soil that is on the shelf. The main thing is NO added nutrients.
Next time try planting right to potting mix and stop with the misting and doming, I never do that and never have any problems. My fool-proof method:
Get some Fox Farms Happy Frog or Light Warrior.
Get some solo party cups (like 12-16 oz) cut a few holes on bottom for drainage.
Soak seeds in water for 24 hours
Fill cup mostly with potting mix, water til some water comes out the drainage holes (usually about a 1/4 cup of water or less)
Make/push a 1/2 inch hole in the middle of the cup/soil top, place seed in hole, push some soil over to cover the seed/fill hole. Remove any excess water from tray, don’t want them sitting in water soaking any more up.
I then put the cups in my tent with the light pretty high up just to keep the tent warm (around 75ish).
4-6 days later the seeds have sprouted and pushed up through the soil. then lower light to avoid stretching.
At that point they may be ready for some more water as well, just enough til you see a little drainage, let it dry, then water, repeat as needed. Learn to gauge dryness by weight, heavy cup = wet, light cup = dry. When you need to water every day, time to transplant and start a feeding program.
I always plant right in the potting mix, never mist, never cover with a dome and never have a problem. I live in the desert so humidity is always low but I’ve never had a problem due to low humidity, too high humidity will create all kinds of problems. I suspect you are keeping the seeds/sprouts too wet and they are rotting and dying. Good luck!
Cheap bag soil i use and have my best results with is pro mix vegetable and herb mix cheap drains well and i add supplement to mine
When seeds don’t pop after 8 days take a tooth pick and spread out the hole you put the seeds in and see if the tails are still white or if the seed has cracked open for the first set of leaves
That’s fine for soil growers but a media like coco or hydro should have seeds started in coco or rockwool, etc.
The point being made to the OP is take care in choosing the right media. I think 80F is a bit high and would prefer to see 74F as ideal temp for starts.
Thanks, Hellraiser. I’m going to try two seeds with the very method you just suggested. Will report back.
What if the tails are white, but the seed looks like when it went into the soil?
You mean sticking out of the ground, like a seed on top of the root, just means it hasn’t shed the seed cover yet, when I see that I leave it for a day to 2 to see if it pushes it off by itself, if not I’ll pull the seed cover off and sometimes the clear membrane under that as well, just have to be real careful.
The seed cover is just barely covered on one pot. No green visible.
I have never had a seed that didn’t lose the shell.
If it’s white then usually they need more time but when it fades to tanish white it has died and then will be mush in the shell it lets you know that you have a bug in your grow medium i can use 2 tablespoons of 3%hydrogen peroxide to a cup of water and use it on the soil and usually fixes it hope this helps you and good luck
Basically when you spread the soil with a tooth pick to see your seed your checking for growth and then cover it back up and check again a couple days later if no growing then it’s probably a bum seed or you got a bug or fungus in your grow medium
I see. Thx. I am getting a diff grow medium tonight, one that has no nutrients added and hopefully is bug free. My next seeds will go into the new medium. Incidentally, I planted Marigolds, cat grass and cat nip, yesterday. We’ll see if I can grow anything whatsoever.
I have one breaking through the soil! I used organic seed starter, which is peat moss and vermiculite, put it in a Jiffy Pot, soaked the soil until a little drained out the bottom, stuck the soaked seed in about 1/4 to 1/2 deep, and put it in the grow tent at 77 F. Boom. Now, it may die tomorrow, but at least the fucker sprouted. How can you grow plants without water? I swear it was the water that made this thing sprout.
Worked! Got one sprouting! Used your method, except I did use a baggie as a humidity thing. Will report back.
Never mind. It keeled over and died, yesterday. Back to square one. 
Must be frustrating, not sure what to say as I’ve never lost a sprout once it breaks through the soil, other than an insect or animal eating it.
I don’t see why you would use a baggie, to me that would keep in too much moisture and retard air exchange. We are not growing swampy plants like venus fly traps that need to live in a terrarium, our plants do not need high humidity to grow well and from what I’ve seen, high humidity leads to more problems like damping off (a plant disease occurring in excessively damp conditions, in particular the collapse and death of young seedlings as a result of a fungal infection).
Sprouts can commonly die from too wet, too dry, too hot, too cold, soil has too many nutes (stay away from any soil with time release nutes like Miracle Grow, hence why I suggested Happy Frog or Light Warrior), or bad water.
I also would not use a soil with vermiculite in it for sprouts, which increases water retention, good potting soils will have perlite in it instead that does not soak up water like vermiculite does.
Ok. I see. More bits of useful info. The only reason I used the baggie, is because I have to run 3 fans to keep the temp in my tent below 80, and the soil dries out like sand in the desert in a day or so. I was using the baggies to reduce the wind on the soil. I’ve got three new seeds in water, right now. I’ll see if I can find some soil with perlite, no vermiculite, and no nutrients added.
Well, you should not have to do that, temps should be controlled by venting out the hot air and venting in cooler air, rather than just blowing around a bunch of air in the grow area. I don’t even turn on my 1 small 6" fan until my sprouts have come up and started growing. Don’t need a bunch of light to get seedlings going so it shouldn’t be so hot that you need to blow around so much air. Once you get the growing environment right, the rest is a piece of cake.
Ok, well, i’ve got an inline duct fan that vents out a chute in the side of the tent, but that only cools to eighty something. My led light has a built in fan, and I had to add a little desk fan to that blows out a screened window on the tent to keep it under 80. My house stays at 67 F. I’ll send you a picture if I figure out how to do that on here.