Hi Nick - We are talking open pollinated varieties for the most part, right, as hybrids may revert regardless of any cross-pollination. It all depends on how stabilized the hybrid is.

That said, most any vegetable will cross-pollinate with its own family if given the opportunity. ;) It's the degree of crossing that varies from vegetable to vegetable. For example, beans and tomato blooms are self-pollinating so the % of crossing from wind/insects is low (about 5%). But members of the squash family, with it big blooms and its need for insect pollination can easily cross.

Commercial seed producers eliminate this problem by using severe isolation of the varieties. For the home gardener who wants to save seed there are 2 choices: grow only the one variety or bag and hand pollinate come of the blooms on each plant and save only those seeds. That's if you want to be 90-100% sure of the seeds. Most of us aren't that concerned and save the seeds anyway. ;) The odds are still in our favor for true production.

As to beans, p. vulgaris (most standard garden beans are in this family) won't usually cross with other bean families but will cross within themselves in a limited fashion.

The primary concern for most of us who save seed is seed-transmitted diseases so extra care mush be taken with disinfection and storage to avoid that - or buy fresh, treated seed.

Hope this helps.

Dave

Thanks, Dave, that did help quite a bit.

So, is a good rule of them that self-pollinating species are generally safe, whereas insect/wind-pollinated species require extra attention?

I know I sound a bit over-concerned, but I'm the one who had to eat some god-awful squash as a kid that was grown from seed my dad would save every year :-) It has scarred me, lol.

So, is a good rule of them that self-pollinating species are generally safe, whereas insect/wind-pollinated species require extra attention?

Generally, that's true. But growing only self-pollinating vegetables really limits you in what vegetables you can grow. It limits you to only using heirloom (open-pollinated), self-pollinating vegetables and well-stabilized older hybrids.

It won't keep some newer hybrid things from reverting even if they are self-pollinating. In other words, if you grow a newer hybrid variety of tomato or squash that hasn't been around for years and is well-stabilized the seeds from that tomato or squash may revert the following year regardless of any cross-pollination that may or may not have taken place. Follow me?

From Mother Earth News
"The easiest way for the beginning seed grower to avoid [cross pollination problems] is to concentrate on self-pollinating vegetables - such as lettuce, okra, beans, peas, and tomatoes - which have flowers designed in ways that discourage or prohibit fertilization by other plants. (Peas and tomatoes, for example, have already pollinated themselves by the time the flowers open!) Still, to restrict your efforts to these plants is to miss out on much of the fun, challenge and satisfaction of growing your own seeds."

And bagging a couple of blooms and hand pollinating them is really quite simple to do and takes only a few minutes. There is a FAQ on how to do here at GW. Had your Dad done that you wouldn't be scarred for life. ;)

Help or make it more confusing?

Dave

Yep, helped again. The more I think about it, bagging and hand-pollinating a few blooms really wouldn't be as much work as I was afraid of. After all, just a few fruits would supply me with enough seed to last years. Sweet.

Hi Nick,
Your question made me think of an old post that I linked below.
Remy

Here is a link that might be useful: saving seed from several plants in the same garden??

Here's another post where I & others discussed this issue in greater detail.

Here is a link that might be useful: Do I need to segregate my varieties?

you should get SEED TO SEED. Great book goes into detail about how far apart plants should be, ways to grow them close to each other and still not cross, I think its around 20 bucks but its worth ever penny