So is it true that if seeds float initially, and eventually sink within a couple hours, they are good viable seeds? Or is it true that only if they sink right away they are viable?
Seeds that sink are viable. I presoak my seeds in a shot glass with mycorrhizal inoculant 48-72 hours prior to planting. I stir when I'm around. Sometimes it takes a whole 48 hours for a viable seed to sink. But they will. I've never had a sinker not sprout. The best thing to do is this. Wait for the seed shell to crack. You should see the white tip of the emerging root. That's the best way to tell if a seed is actually viable without having to plant it first. Then plant that shit!
Theres no way to tell if a seed is viable by looking at it. The only way is to germinate it. If a seed looks unhealthy, immature or has a weak seed coat...it probably is a dud
I just explained how to determine whether or not a seed is viable, using visual confirmation. A soaked, cracked seed shell with an emerging root tip IS SPROUTING, therefore viable.
Thanks for the answers everybody. Yeah, I first picked out only the fullest, hardest, darkest colored seeds with black "lines". Then I put them in water for a presoak. They've been submerged for a total of about 24 hours right now. Should I leave them in water until the root pops through or should I take them out now and plant them..? And also which "end" of the seed am I looking for a root to come through? The "pointed" end, or the end with the little knot/indention?
Leave them in the water until you see the root tip begin to emerge. I use clear, plastic "shot glasses" so I can see when the seed shell has cracked without having to handle them. Wait until you can see at least some of the root before planting. Then you KNOW it will grow. Root end down, pointy end down (that's the end where the root emerges), or plant the seed on its side if you're not sure. The root knows which way to go.
Got it. Reason I asked about which end it emerges from is because I think I can see a tiny little change in the shell of the seed on the pointed end
So now all seeds are cracked and you can see a white root inside, but they are not emerging from the shell yet. Should I plant them now, or wait...?
Go for it. I only mentioned "emerging from the shell" because I've gone to bed with the shells totally intact, and waken up in the morning with 1/4" tap roots waiting to move into some soil. Don't overwater your seedlings. No need to water until some drains from the bottom of your pot. Just a little around the seedling itself. As it gets bigger, widen you watering footprint. It's really easy to drown seedlings by keeping the whole pot of soil wet. You'll know if you're not giving them enough. They will wilt.