In my area, one can pick them about a week before natural seed fall and they still sprout well. As long as there is a little lightening of the green colour at the base, where it joins the cap, they will still grow. Someone in your area will have to comment, as I have no idea. Here, in the great white north, grin, it's the end of September or early October before natural seed fall. I suspect you could be 2 weeks early and still be OK, just have a smaller tree the first flush.

Jocelyn

So wait until they are falling off the trees? Don't try pulling acorns off?

For the species that separate from the cap, I think you could safely pick them off the tree when the nut is essentially all tan/brown with just a little hint of green AND when it separates easily from the cap with minimal force/pressure. If you have to fight with it, it's not ready. If it gives in easily, it's ready. Probably the same is true for species that retain the cap longer, as long as they look fairly ripe and come off the stem without much force they're basically ripe enough for germination purposes.

Time, of course, will depend on species.

Read up on the actual species with which you intend to work. Oaks have fairly wide-ranging differences in terms of seed (acorn) maturity, etc.

+oM

isnt there something about them floating also ...

or was that a dream??

ken

Not sure about floating, but you can cut one lengthwise and see if the seed leaves are firm and waxy. The embryo needs to be slightly harder than the seed leaves. If the seed leaves are soft or have a lot of milky fluid in the centre, try again in a week or 10 days.

If they float, they are infested with a beetle worm that will render the acorn incapable of germinating.