I would say by visiting and seeing first hand what you are investing in. I support three organizations. Seed Savers Exchange. I have been there but not until last year and I have been a member since 2001. I joined not to support them but to have access to the annual seed savers book as a resource for heirloom seed. My focus and desires have changed since 2001 and I continue to support SSE because they are an established group, have a good reputation, and I find myself always looking up something in the Annual seed savers book and have meet some very dedicated seed savers through this book and obtained some additional information about varieties from this book. After my visit last year and the resources SSE has I will continue my support.
I support Southern Seed legacy project. They are a part of the Univ. of Ga. anthroplolgy dept. and this organization started out as a reserch project for a couple of heirloom seed savers and turned into a seed bank. The organization has had a lot of operational issues. Most who stumble across their website look at them as a resource for rare seed and pay the donation fee to join and have access to those seed. I did the same in 2001. But they are very small not a seed wharehouse and many of the varieties on the website are not availble. The varieties don't fit into any proper classification and not a lot of information on the website about the seed. They came also be hard to reach. I continue to support them because I realize they are not a commercial seed outlet. They are all volunteers and what they do is research on southern gardening and seed savers. They host an outstanding informal seed swap that is open to the public, no need to join to attend. But I believe in the mission of the organization and the integrity of its people to preserve southern heirloom plants. I have also meet them and the staff and been to the swaps.
I support the Appalachian Heirloom Seed Conservancy (AHSC) I joined AHSC after attending the fall conference in 2004. I wanted to meet seed savers and participate in a seed swap. I had purchased seed from Bill Best at the Mountain agriculture center and he hosts the conference so I it was a chance to meet the Bean and Tomato man of Kentucky. The wife and I had such a good time at the conference that we plan to attend every year. Their mission is to preserve Southern Appalachian varieties, varieties I am familiar with and grew up with. A large percentage of the seed of Appalchia is beans and tomatoes, my two favorite crops to grow.
To summerize, support a local orgaization that preserves the seed of your region, attend a conference, a seed swap if offered and get to know the people involved and what they are really about.
If nothing local then start at the foundation(SSE) and work out.
If seed preservation and maintaining our genitic diversity are a priority and a concern for you. Always buy your seed from a company whose mission is to promote and preserve heirloom varieties. Such as Bakers Creek and Southern exposure Seeds. Steer away from seed companies that offer mainly hybrids and some heirlooms. These companies have started to offer heirlooms only to reach a new market and pad their wallet some more. Their main interests is what can make a profit and not in preserving anything. Rodger

Thank you so much rodger for all your input...that is really what I was looking for...personal experience/views.

I agree with the comments made by Rodger, who posted a nice summary. As an active SSE member, most of my own efforts are in support of that organization; but all of those listed above are stewards of diversity, and can use use your help.

I will add one more organization to the list: Native Seeds/SEARCH, which focuses on the vegetables & edible plants of Mexico and the desert Southwest. Ruthie, with your similar climate, you might find them interesting. They offer an enormous selection of Native American varieties through their retail operation.

Several other preservation-oriented organizations in the U.S. have fallen by the wayside, and even SSE's membership has been declining in recent years. The news is not all bad; the number of companies specializing in heirlooms (such as Baker Creek & Sand Hill Preservation) has increased during the same period, and more heirlooms are being offered.

But perhaps this increased commercial activity has come at the cost of reduced support for the remaining public, non-commercial organizations that act as stewards of diversity. If this trend continues, it would represent a serious problem... most of the smaller seed companies are family operations, and are just one death or disaster away from closure. Hopefully, this will be a call to arms for a new generation of seed savers.

Which leads me to my final point. There is another way to support diversity other than, or in addition to, your monetary support. That is to adopt & grow endangered varieties for the long term, in place of those offered by mainstream agriculture (which are mostly hybrids). The AHSC, in particular, preaches this... and so do I. There are so many wonderful heirlooms; if every vegetable gardener on GW were to adopt just one & share it with others, it could have a tremendous impact.

Seed saving is not as difficult as some might think... and there is plenty of support right here on GW. ;-)

This is such great information...I hope that everyone that reads this thread takes it to heart and supports the organizations in their own ways...whether it is with money or some other way...we really do need to do what we can...thanks zeedman for your info too...

So how do you determine how to support the seed savers...

In Britain we support the Heritage Seed Library. This is part of the Garden Organic organisation, aka HDRA. There are currently 11000 members supporting, but far fewer are Seed Guardians. Seed Guardians are members who grow one or more varieties and then send their seed back to the Seed Library. There they get germination tested, packaged and distributed to the members, who choose from the annual catalogue. The seed library also keeps secure reseve seed stocks, should accidental crossing occur at a Seed Guardian and every batch can be traced back in case of a purity problems. Every member can receive up to six choices per year from the catalogue. The seed library keeps about 700 varieties. The difficulty we have in Europe is that because of EU regulations, seeds not on the official seed list cannot legally be bought or sold. So no money changes hands for the seeds. Club membership with benefits (six seed packets) is ok.

In addition to this, the Heritage Seed Library publishes Seed Exchange pages, where seed savers can advertise their Haves and Wants. These are then sent for stamped, addressed envelope (no money changes hands), although some people accompany their requests with a donation of extra stamps. There are many more varieties in the Seed Swap pages than the Seed Library administrates.

The Heritage Seed Library also organises Seed Swaps during events at their show gardens and is involved with Seedy Sundays and similar events.

There are a few other, smaller seedsaving groups and organisations in the UK. Some tiny commercial enterprises, who offer seeds in exchange of club membership, also specialist seed companies who sell only heritage varieties, such as Thomas Etty for example. There are also companies who sell plants, rather than seeds of those varieties where selling seeds is forbidden under EU regulations. Selling plants is permitted, even if selling seeds of these plants is not. I support these companies too.

Here is a link that might be useful: Heritage Seed Library url

Great points, everyone! I am also a member of the Seed Savers Exchange. Though, over the years I find that I make fewer and fewer seed requests. Zeedman makes such a good point about adopting seeds to maintain. There is indeed, some great support here on the Gardenweb.

I just wish we could get gardeners to adopt even just ONE thing each to maintain and share with others, and that as gardeners we wouldn't all go with fads. There are so many good varieties out there which are not superior enough to out compete the most popular varieties. One can actually find some of these varieties through correspondence with Gardenweb members.

As time goes by I'm more and more inclined to simplify and to concentrate on fewer, but less popular varieties. Our family heirlooms will stay, no matter what popularity (or lack thereof) they enjoy.

Here's an anecdote about an unsung seed saver "hero." When I was in grad school I mentioned my seed saving to a number of professors. One prof, then, shared a handful of bean seed, which he called "Ralph's Italian." He told me that previously (probably the 70's) he had lived in Clarks Summit , Pennsylvania and that he got this seed from his barber, named Ralph. I believe Ralph was Italian, and personified some of the best things about some of the old timers from that ethnic background. He was very social and friendly. And, he apparently loved to garden. He had this bean, which he loved. He loved it so much that he would raise a lot of seed every year and keep some in a shoe box in his barber shop. When the conversation turned to gardening he'd tell customers about his bean,... and offer them a handful of seed! Years later my prof gave me some seed. I keep it going, even though I have other favorites. This is not a popular heirloom. But it has it's place and Ralph was faithful to pass it on! He probably didn't pass on much else. But what a great contribution he made!

George
Tahlequah, OK