Rick,
Good questions! The minimum contribution is 3 packets of seeds of any variety. It could be one pack of radish seeds and two packs of lettuce seeds....or it could be three packs of the same item, if you wish (say, three packs of coneflower seeds). I hope that everyone will atleast try to contribute much more than three, however. This swap is only as good as its contributions.
a three pack minimum is sort of my way of acknowledging that some people may just be starting out and not have much yet. I want to be as inclusive as possible, but I am depending on the generosity of the majority.
...Also, don't discount 'old' seeds, old seeds can still be very good
just make sure you label them as 'old' or with the year so that requestors know what to expect. I've had great luck with 'old' seeds, so that doesn't really phase me. I suspect many other people will feel the same, too.
We do have a lot of members on ATP, but only just so many active members. I imagine the first swap won't require a cap on the number of participants. If we do get a crazy number of members to the swap, I may be forced to push back the send-out date, but I don't think it will come to that.