How do you keep your seeds pure?
I was reading in Carol Deppe's book, "Breed Your Own Vegetable Varieties" that what are considered correct isolation distances in gardens that use chemical 'cides are not the same as required by organic gardens. Organic gardens have many more pollinators and so much more pollen is spread about. Conventional gardens tend to have 3 types of bees, at most. Whereas organic gardens will have over 100 kinds of insects pollinating.
She found that the USDA distances used by all breeders were not keeping her beans pure (3' for beans) and looked further into this and found that for most inbreeders (tomatoes, beans, peppers etc) the 3' to 8' distance wasn't nearly enough. I found this revelation interesting, that of course there would be a lot more pollination activity in an organic garden. And I have had crosses show up when I thought all was well with isolation.
One suggestion she has that I have used is to grow beds of alternating species of plants so the insects have to pass through non related plants and clean the pollen off while doing so. Putting folwers inbetween, say beans, is effective as the pollinators will visit the flowers and get rid of the bean pollin before hitting the next kind of beans.
I know about Brook's Tufbell isolation cages and of course for some crops you can plant things at diifferent times so no one is flowering at the same time.
Any other ideas?
By The way, the book I mentioned I highly reccomend.
This is very intresting and something that makes real sense when you think about it.
I intend to get the book right away.I am maintaining proper distances and isolating(per Brook's tuff bell) but the insect population in an organic garden is way higher and much more diverse than a conventional one.Everyone should agree if you just think about it.
You are right on with your observations about the diversity of pollinators and issues about distances. I have almost no European honeybees working my crops now yet my pollination seems adequate. Lots of other ones. I've taken to growing out only one or a few varieties of any crop for seedsaving at any one time. With some crops I can use temporal spacing to avoid crosspollination. With others I bag and hand pollinate, using the unbagged fruit for selling to customers.