Answer: You have asked a good question. Heirlooms are open pollinated, and when it is a case of an heirloom hybrid such as Marglobe or Rutgers tomatoes, the cross has been stabilized so that it will come true from seed. But, in some cases plants (such as peas) are self-pollinators and in other cases (such as squash) the varieties need to be isolated or hand pollinated to reproduce true from seed. Then, too, some plants (such as peppers) are primarily self pollinating but will occasionally cross due to bee activity if planted adjacent to other varieties in the garden. You may also find that some traits such as flower color, for instance, are dominant and thus you need to save extra seed from recessive colors in order to preserve the mix. Finally, seedlings are subject to natural variations, so for all these reasons you need to be careful as to how you collect the seed to be saved in order to get the best results possible from year to year. You may find this article http://22.214.171.124/nga/articledetails.taf?id=293&kwd=seed&A... about OP and hybrid seeds of interest.
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