How long does it take for a lotus seed to germinate without scarifying the seed?

Question

How long does it take for a lotus seed to germinate without scarifying the seed?

Answer 1

Forever. You need to scarify.

Answer 2

The outer shell is so hard that I think you have to scar the seed. I don't know how it occurs in nature but the process is relatively easy for a gardener.  I have started many lotus plants from seed. I use a small grinding tip on my Drumel tool.  I simply hold the lotus seed firmly between my thumb and index finger while slowly grinding down the end with the "inny" belly button.  I grind down to where I just see the cream color of the inner shell. Then I put the seed in a shallow, plastic bowl with an inch or less of dechlorinated water. I set the bowl on an electric heating pad under an intense grow-light and change the water daily. Within three or four days, a little green sprout appears. An alternate means is to scar the seed on cement or use sandpaper and then drop the seed down in a tub of water outside that you may already have a lotus plant growing in.  The sun and warm water will naturally do the trick.

You could wait a VERY long time for a non-filed lotus seed to germinate, as this statement I found on the web attests to:

"Seeds of the sacred lotus (Nelumbo nucifera) found in a peat deposit in Manchuria and estimated by radioactive-carbon dating to be 1,400 (±400) years old, rapidly germinated (and subsequently produced flowering plants) when the seeds were filed to permit water entry."