Here's some online info about saving seeds from spinach:
http://www.highmowingseeds.com...
wind-pollinated
isolation distance up to 1/4 mile
consider staking the plants: some get 3' high
Here are some tips for pros:
http://www.seedsave.org/issi/9...
Seed production can take 4-6 weeks past the eating stage.
Remove the plants that bolt fastest, you don't want fast-bolting genes.
The pollen can blow around for MILES!
(But probably many neighbors will pull it soon after bolting.)
"Leave one male plant for each two females to ensure pollination. "
That site kind of hinted that the seeds don't jump off the plants the way poppy seeds do. You might be able to let them "dry on the vine" until the plants turn brown, chop down the stalks, and then even need to thresh them a little to get the seeds out! I don't know, I never tried spinach.
