There is nothing wrong with directly in the medium unless the medium is not up to par, meaning like its got old garbage in it and lots of molds.
You will never get 100% germination rate over the course of your life, shit happens and sometimes seeds are duds but 5 outa 6 duds seems a bit off.
Lets break it down.
The way I like to germinate is by scarfing the seed with an emery board, then soaking for 12hrs, after this I plant directly into the soil.
I will plant them about 1/2" to 1" deep and keep the top later of the soil moist but not wet. misting every day. I sometimes even put a little cup over the spot where the see was to keep humidity high in that area, remove this once its sprouted though and give it fresh air once daily.
Once the seed shell cracks it has germinated if a little root tip is exposed it is also classified as germinated, A lot can happen from germination to sprout. and this is where most users have the issues, ranging from overwatering/overfeeding, to heavy mediums unforgiving of seedlings or mishandling of the the little sprout.
I would suggest an alternate method to germinating till you get the hang of it, I would also reach out to the company and see if they can spot you a few more, maybe there was a bad batch.
Best Of Luck!
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