Few basements in the Eastern US, without mechanical de-humidification - even if no actual water is present - have dry-enough air for long term seed storage. Perhaps if you have a central air unit that does a good job of controlling humidity (including the basement,) your seeds will do okay. What you get down to, assuming good conditions, is the average viability of individual seed types. That's fairly easily researched on the internet.

Cucurbits should be fine. I planted some 5-year-old cucumber seeds, and they had a nearly 100% germination rate.

So most of them should be OK next year. The only thing I'm weary about are the onions, should I even bother saving them? I have about 150 seeds of both of the varieties I bought left over.

I suppose in December or so, I can take maybe 10 out of each packet and see if I can sprout them on a paper towel, just to get an idea how viable they are.

I've had decent luck with leek seeds even after 3 years (about 70% germination). Don't discount those onion seeds just yet. They may surprise you.

Rodney

I am not following some of the responses. The OP says in a ''...basement in a Ziploc bag...'' some responses say a basement is not dry enough.

Elsewhere is fairly commonplace to suggest Ziploc bags.

Someone, somewhere, suggested using a jar with a screw cap where moisture might be a problem.

Usually smart to put some silica gel packets in your ziploc bag. If held in a moist environment, the seeds and the envelope will absorb moisture. Put those seeds and that seed packet in a ziploc bag, and the moisture is still there. Silica gel will pull the moisture away from the seeds and the seed packet. Ziploc bag, sealed jar ... no difference. Cool and dry is the recipe for seed preservation. Fridge is even better, because the air is cooler (and, as it turns out, also drier).

I found someone at Purdue who suggests a screw cap jar with rice in the bottom.

I always thought that uncooked rice was a good dessicant, but there seems to be some controversy about that. It is said by some that rice absorbs water really well from boiling water, but not necessarily from air. I am told by electronics engineers who use dessicants for their circuits that rice works best as a dessicant only if it is specially dried to start out with. Salt is a good dessicant, which is why salt in salt shakers clogs up. I suppose rice works a little bit, which is why it is added to salt shakers to keep rice flowing freely. So, if you want something cheap, off-the-shelf, and effective, salt is probably your best bet.

Allegedly, calcium chloride is an excellent dessicant. I think that's what you use for keeping your pickles crisp. If you have that around, use that. Non-dairy creamer is supposed to be pretty good as well.

"The only thing I'm weary about are the onions, should I even bother saving them?"

Sure you should. Just because they may not give you 90% germination doesn't mean they are worthless. All we are saying is their germination rates fall off faster than many other things do.

Albert - not sure what is confusing but ziplock bags can trap moisture inside so some use ziplock bags with dessicant packs in them but many others use only paper that can breathe so no moisture is trapped. The point about basements is that since they are below ground level the humidity is usually quite a bit higher than it is upstairs. So is a ziplock in a basement better than paper? Yes. But the basement is the primary problem.

Bottom line - there is no one right way but it must be cool and dry, especially dry.

Dave

oops Dan and i were typing at same time.