I have used the desiccant that comes in some cookies and dry goods. It works pretty well. I also sometimes wrap the seeds in paper towels before putting them in ziplocs in the frig. It helps to keep them dry and out of the light.
I like to dry my seeds on the plant. I do have to watch them to make sure they aren't released before I get to them.
Tip 1: Make sure the seeds are mature enough to save. Green seeds will not germinate.
Seeds are best dried naturally. I let mine dry on the plant. Clean them and store them in paper towels or envelopes in a ziploc bag.
Tip 2: Label the bag with something indelible or put a piece of paper in the bag with the date, name of the seed. I have a few mystery seeds because the permanent marker wore off.
Store seeds in a cool, dark, dry place at a constant temperature around 40 degrees. I live in a warm place, so, I keep mine in the refrigerator.
Tip 3: I store seeds in paper towels or envelopes inside a ziploc bag. The paper helps absorb any extra moisture in the bag. If you have a lot of seeds, package only the ones you will use in a single planting in one envelope. Keep all the envelopes individually labeled with the collection date and name of the plant in a single ziploc bag. Take out only the seeds you need and leave the rest in the refrigerator. I have lost seeds when I took out all the seeds and lost the bag. Seeds don't like to go in and out of very different temperatures. Condensation can form inside the bag and cause them to get moldy or the changing temperature could interfere with germination.
Tip4. Every once in a while, at least once a year, clean out the seed box. Keep an inventory sheet in the box of the seeds you already have and how old they are.
Tip5: If seeds are marginal on the dates, take a few out and do a test germination by sprouting about 10 seeds on a moist paper towel to make sure they are still good and get an approximate germination rate. Some seeds don't last as long as the chart says it does. For me corn and zucchini lose germination to quickly and beans and dill seeds I have collected have still germinated even when they were 13 years old.
Tip 6: moisture and heat shorten the lives of seeds. Keep them at a consistent, cool temperature and packaged to stay as dry as possible. When you buy seeds don't buy seeds kept outside in the garden center where it is moist and the temperature is not controlled.
Tip 7: Catalogs come out in December or January. They offer a wider range of seeds and plants than what you will find at the store. However, be mindful to make sure what you order or buy from the store will actually grow in your microclimate. Some varieties will be more suitable for your area than others. Try to get together with others to buy seeds in bulk to cut shipping costs. Seed exchanges are good, but try to exchange locally. Some seeds are restricted and require inspection by the Ag department before they can be sent out of state.
Tip 8: Presoak hard to germinate seeds overnight. Keep only the seeds that sink.
Tip 9: Some seeds need to be soaked or scarified to improve germination. Some seeds need minimum or ideal temperatures to germinate. Otherwise they will not break dormancy.
Tip 10: Some plants don't make seeds, take a long time to mature, or are not reliable from seed. Propagate from cuttings, grafting, or divisions instead. Example avocado, rosemary, artichoke, French Tarragon, and most citrus
Tip 11 Unless you get clones, all seeds will be different. Genetics, environment and culture all play a part in making a fruit or vegetable taste good. Hybrid seeds will not breed true if saved. It takes several generations for a hybrid to stabilize. That is why some hot peppers are not and some varieties of corn vary from batch to batch.
Tip 12: Sometimes the seeds or the planted seeds get mixed up
Orthodox seeds can be saved. Unorthodox seeds like chayote cannot as the seed cannot be dried successfully and remain viable.
Most seeds will keep 3-5 years
Exceptions: I have kept these seeds and they have still been viable much longer or shorter than expected.
Corn = 2-3 years.
Zuchhini 2-3 years with reduced germination
Beans, dill = good for 10+ years.
This is from Iowa extension service
Approximate life expectancy of vegetable seeds stored under favorable conditions.
Vegetable Years Vegetable Years
Asparagus 3 Kohlrabi 3
Bean 3 Leek 2
Beet 4 Lettuce 6
Broccoli 3 Muskmelon 5
Brussels sprouts 4 Mustard 4
Cabbage 4 New Zealand spinach 3
Carrot 3 Okra 2
Celeriac 3 Onion 1
Cauliflower 4 Parsley 1
Celery 3 Parsnip 1
Chard, Swiss 4 Pea 3
Chicory 4 Pepper 2
Chinese cabbage 3 Pumpkin 4
Collards 5 Radish 5
Corn, sweet 2 Rutabaga 4
Cucumber 5 Salsify 1
Eggplant 4 Spinach 3
Endive 5 Squash 4
Fennel 4 Tomato 4
Kale 4 Turnip 4
Table modified from D. N. Maynard and G. J. Hochmuth, Knott's Handbook for Vegetable Growers , fourth edition (1997)
https://hortnews.extension.iastate.edu/ ... elife.html