Just for laughs, and getting pretty sick and tired of soaking seeds in boiled water, waiting a few days, repeating... I decided just to clip the side of an albiziaseed and stick it in the pot with no other preparation.
...and got 99% germination!
Albizia is a horrifyingly hard legume seed, and needs multiple soaks before it will bloat. But a simple clip of the side of the shell, and the seedling was emerging in less than a week - much sooner than the soaked seedlings were emerging.
Pictures show the clipping procedure, a closeup of the cut, and the emerging seedlings.
It's actually pretty amazing how reliable this technique is. I always wind up damaging a lot of seeds though.
I was recently working with dozens of maypop (passiflora incarnata) seed, which takes 60 to 90 days of stratification to get any germination. I forgot to start stratifying it last year, so as a last resort I took the nail clippers to the seeds and got 63% germination within about one to two weeks.
For especially good results with this technique, try to locate the hilum on the external part of the seed coat, which is usually where the radicle is located within. Chipping away that part of the seed coat will allow the radicle to extend without encountering any obstacle.
Also, wear eye protection - hard bits of seed coat seem to fly at ones face with deadly accuracy.
Here's another technique that works with some hard seeds. For some seeds, the coat is hard except for the very edge, where the two halves of the seed coat are joined. This area tends to be fragile, and applying pressure to the sides can shatter a piece of the seed coat away. Think of how you can pop a sunflower seed open with your teeth, it's the same idea (but I'd recommend using a bench vice instead of your teeth).
posted 4 years ago
I do find that as I close my eyes for the clip, the piece invariably hits my eyelid.
The size of my clippers does limit where on the seed I can clip, and luckily it would appear that means albizia seeds get clipped perfectly for the seedling to fall right out. 99 from 100 seeds so far.
I like to use the clipper trick when planting mustard seeds.......
OK - that was just ridiculous - lol.
But on a more serious note - another option that I've grown to love is to use a piece of sandpaper to scuff up the outer surface of the seed - sometimes I scuff into the edge until it wears right through the tough outer shell. I've had really good luck with this method. I've tried the clipper method in the past and it worked pretty well when my eyes were younger and my hands were steadier - haha.
"If some is good, then more is better and too much is just right!"! ~ Shayf