Seed Germination: Coir vs Sphagnum vs LECA

[PalmsInBaltimore]

I have the first update on a little nonscientific experiment I have going trying to germinate Pinanga coronata (var kuhlii) and Licuala peltata seeds. 
 

Received the seeds last week from @NatureGirl and soaked them for a few days. I divided the seeds into three groups for each species and planted them in different media to see if one would germinate noticeably faster than the others. So one group of P coronata and one group of L peltata seeds went in coco coir, another group in sphagnum moss, and another group in hydroton clay balls. I put them in Tupperware containers with lids that seal in the moisture and create a little greenhouse. A cheap wardian case basically. 
 

Here they are from arrival to preparation to planting:

The photo shows them shallowly planted but I actually lightly covered all the seeds with enough medium to keep the direct sun off them. 

Well, less than a week later, the first seeds have germinated. Unexpectedly, the L peltata are popping first. Hopefully it’s visible in these photos but the tiny white button on the side of the seeds is the first sprout!!

(The start of a new plant, hopefully!)

(The top central one has a tiny little cotyledon emerging)

(that little white dot on the seed is a sprout)
I wish I could’ve gotten a closer image but the phone wouldn’t focus on the seed when I was an inch away. Two seeds in the coco coir and one seed in the moss have burst!

No sign of anything from the P coronata seeds yet. I’m surprised the L peltata popped first. They’ve been outside this whole time. Days around 95°F, nights around 70°F the past week. 
 

I’m debating whether to move the seeds in the clay balls to a different medium if they don’t do anything in a few weeks. I thought maybe the clay balls would keep the seeds moist with no chance of being too wet but maybe they aren’t keeping the seeds moist enough. We’ll see 

 

[PalmsInBaltimore]

About a month in the preliminary results are:

-moved all the seeds inside because August here has been weirdly cool. They’re on a heat mat staying steamy 24 hours. 

-no germination yet on any of the Pinanga coronata so still waiting. It’s only been since July 27.

-with the Licuala peltata, some radicle emergence in the spaghnun and coir as shown above but those were consumed by fungus so disappointment. Should have applied antifungal from the start 

-in the clay balls there was one seed that had sprouted and actually was sending out a sinker. Between concerns about fungus contamination and the clay balls accidentally grinding off the root, I moved this one to some spaghnum in its own container. Here’s a picture from a few minutes ago:

it’s in moss with 9 other L peltata seeds that haven’t sprouted but were in the coir and moss containers where some fungus ruined some of the seeds there. 

My concern now is whether to pot this one up in a little seedling tray that will continue to get bottom heat or leave it in there until the first leaf or at least until the plumule emerges. Not much species-specific data on these available but it seems to be a remote germinator. My other concern is if the sinker will go down more than like 2-3 inches it may have to be moved because there’s only about that much depth of spaghnum in its current container.