You might have gotten a bad batch. It happens to every seed company. If you go to walmart or another big box store try a pack of the cilantro they probably have out there. It doesn’t sprout when it’s over 80F really good for me but it hasn’t been that warm for long at your house. So it might be the seeds themselves.
I transplanted two T squash so that is 5 I have in their permanent pots outside. Still bothered by tomatoes, and there was a Big Boy and 5th of July and Cherry Punch in the backup set of tomatoes that looked very good, so put those each in a large container. I have no idea how many tomatoes in large containers are out there now. I'll check on that tomorrow.
Now, I have a number of cucumbers that need to be in large containers but I am now out of potting soil mix. Have to go to Lowes soon.
Sunflowers:
I have five or six or some number, of sunflowers in small pots that need out of there. I think I'm going to actually dig holes in the dirt next to the back wall, and stick them in there in a row. That part is dirt not covered by the landscaping material. That is where I had beans last year that were baked by the sun as they were attached to the wall. I'll do that tomorrow. I have one of those round hole metal thingys to punch in the ground to plant bulbs. That should make the holes.