I have a stack of seed catalogs that I look at, but I do like to give preference to seed companies that are located in our general area, if possible. Although they may or may not grow their seeds in the same area that they are located, they usually carry only seeds that grow well in this region. Plus, they often have trial gardens to test their seeds and ensure they do grow well in our region.
Some varieties grow well everywhere, but since others do well in particular climates, I figure I have the best chance of success if the seed has been tested in a garden with a similar climate as mine.
Seed packet size is also a big thing for me. For many veggies, I just want to grow a couple of plants, so would rather buy several small packets than one big one. I’ve ruled out buying seed from some companies just because I know a big part of the packet will end up going to waste.
Cost enters into it too. I’ve discovered I’m a pushover for any seed packet that remotely interests me and costs under $2. But if you have to add huge shipping costs on top, I’m not going to bother ordering it. I tend to order those seeds that are unique and that I can’t buy from a local store, then add in others only until it pushes me into an additional shipping charge.
I have a special place in my stack of catalogs for Seed Savers Exchange. I like the idea that they are committed to saving heirlooms, and that members keep those plants in existence. They are often the best source for those hard-to find heirlooms.