Was the seed fresh? Did you provide some bottom heat to encourage germination?

Fresh seed and no heat pad. I am thinking since it is a tropical it might need higher temps for germination. But I get peppers and tomatoes to sprout with no heat. So I don't know.

I grew Culantro (E. foetidum) from seed without bottom heat or even my grow light. Just sprinkled seed on top of soil and stuck in front of a sunny (but not direct light) window.

I was surprised how well it grew and seemed okay with my less-than-humid house environment.

Was yoru seed commercial? If not it could be it was harvested too soon and wasn't "ripe"?? There wasn't any mold or fungus that developed on the soil was there? Might also be that the soil was TOO moist, possibly from the plastic wrap. Just some guesses...
CMK

It was a couple years ago that I grew them...sorry I can't remember how long it took for germ :-( Think it was some time though- and they did take a long time growing inside to bulk them up to a decent size.

What is your soil mix like? Does it retain water easily? Usually I dislike very peat-y based seed starting soils because they dry out TOO fast, but it may be good in this instance, since Eryngiums don't like it wet.

Ps. Not sure if it is of any interest, but I noticed the Culantro plants (like Eryngiums in general though) have tap roots. So if you are going to transplant be careful- those roots are brittle and may break easily.

Hope you have more luck with your next batch of seeds :-)
CMK

I grow culantro for personal use in Princeton, NC. The seeds I used are from plants I grew last season so they are fresh but they take a long time to germinate, even a month!.
The key is to keep soil moist and shade, I use compost as the growing medium. I have seeds from 5 years and they still germinate but they were collected from the plant at the right time which will make a difference. I dont know where you live but if you trow some seeds outside in a container with compost right before the first snow you can see the seed germinating after the last frost. I did that myself as a test and the plants from those seeds are twice as big as the one I germinated after the last frost here in NC. I might be going overboard with the info but Culantro plant will survive a NC winter as long as you cut all leaves and lay a thin layer of mulch before the first frost. I have a Culantro plant 4 years old who survived all those winters and I still get good leave for my salsa! If you want when my plants get fresh seeds I can send you some!

Even thou cilantro is a cold/cool crop, yet it requires certains soil and air temperatur to germinate normally. At cooler temperatures it will take much longer. The sam is true about parsley, chive, onions.

Also viability of seeds is in question. Were they fully developed? how they were kept ?...

Another issue is : how deep you plant them .
For seeds to germinate , they dont need any food to do that. You can germinate seeds in coffee filters, paper towel, water...The role of medium is to provide moisture. Once the seed grow true leaves, then they will need nutrients.

Normally you cover the seeds equalent to 2-3 times their diameter. Throwing it on the surface will not work, me thinks.
Yet another thing: For seeds to germinate they do not need light. But once they germinated will need it.

Why is this herb classification called foetid? Not a great selling point.

Has nothing to do with selling. That would be part of its botanical or scientific name. Scientists get to name things they discover or as in many plants, the person categorizing and naming them got to choose. Someone obviously thought the plant stunk.

FataMorgana