Mark the old float or sink is a great indicator that many use. Their is one exception, the coconut seed.
It can float for months as evident of them popping up on deserted islands


My experience in how germination happens is that my Big Mama fertilizers herself. No, she is not hermaphrodite but with over 20 pups under her skirt, some of them bloom and fertilizer her blooms (several of the pups have 3' trunks. I know for a fact they can get fertilized from their pups but hermaphroditic individuals do exist. So she is an all in one production center.
Check to see if you have pups growing around your mama needle.They can be hermaphroditic but its not real common.
I have had big bull needles near her in her first 10 years and they bloomed and that might have got her seeding before her pups began. The bulls have been gone since the vortex in 2014 and 2015.
Here is old mama, around 47 feet in circumference and around 8' tall as of this morning but don't think she will grow anymore. We had flurries overnight as we sometimes do in winter but its 50* or warmer now.


Mark here are some old seed patches below some female blooms. They have dried out and not identifiable.


Here are some old male flowers but they to have fried up and its hard to identify their look


The Needle Palm has long been known to be scarce and endangered (I think it is in some north Florida counties) and the reason for this is poor seed distribution among and plant poachers but below is a photo of their known trait showing how the needles all over the trunk sometimes keep seed from falling off the palm so the seeds are stopped from germinating.
IF you look closely you can seed seedlings that germinated and are trying to survive among the needles all over the trunk. This is the demise of the needle palm and they should be cleared of old blooms and seed yearly


I like that photo showing the seedlings and I will harvest them today or tomorrow. I've yet to clear out any 2019-20 seeds yet but like Kevin stated, it takes a long time for germination and even longer for growth.
That's why its always good for people in temperate zones to get the biggest specimen you can find for slow growing palms.
Thanks Mark