The old guy sieves his seeds so the small ones are thrown out. I like the idea. Do your small seeds germinate and grow as well as the bigger ones?
My big seed is big and always big...and the small seed is always small.. the fert or growing conditions dont determine seed size. There is never a mix of big seed and small seed...
Germ is same regardless of size... now color seems to be the true variable as light color seed never germs as well as dark seed.