Hi, MadHacktress. I can understand being overwhelmed trying to save seeds from 120 varieties! A clarification, if you don't mind... What would be the difference between selecting some varities to grow in the secondary garden for seeds versus alternately selecting a small number of varieties to save seeds (the ones you would grow in the secondary garden) from the plants in the main garden?

If you have the room and the time I'd say go for it. Some definite pros I personally see is that some vegetables, like lettuce, onions and cabbage we like to harvest before they bolt. After they do so, we tend to use them only for their seeds. By having separate gardens you can harvest all the vegetables from your main garden to use as food and not have to leave any for collecting seeds. Also, you can definitely maintain purity better with space and buffers.

Some plants you will probably have to do a little bit more preventative measures even with the distance (such as corn whose pollen can blow for miles and miles and miles and.....), but I think for the most part it will make it easier if saving 100% genetically pure seed is a concern.

That being said, I would not take up space in your seed garden with crops that do not tend to cross anyways. Beans (P. vulgaris cultivars especially) and peas being the most glaring example. But if you are growing different cultivars of corn or squash for example, a seed garden would help immensely IMO.

but now I want to start growing out seeds for my own use from more difficult-to-save vegetables

I'm just curious as to what vegetables you think are difficult-to-save? Have been a seed saver for over 40 years and never found any garden vegetable that was "difficult". Corn is the only thing that comes to mind that requires any special effort.

And why would it take a whole garden to produce enough seeds to save for future personal use when most plants produce more than enough seeds for several years?

Dave