What to do now
Mildest step first.
- Check the packet year against the list below; seed within its range is usually fine.
- For older or doubtful seed, roll 10 seeds in a damp paper towel, seal it in a plastic bag, and keep it near 70°F.
- Count sprouts after 7–10 days (peppers can take 14): 8 or more is good; 5–7 means sow more thickly.
- If fewer than 5 sprout, buy fresh seed, and store the rest in an airtight jar in the refrigerator.
How long seeds last
Seeds are alive, and they age slowly in the packet. How long they last depends on the crop and on how they were stored. University of Wisconsin–Madison Extension gives these typical lifespans for properly stored seed: onion, 1 year; corn and pepper, 2 years; beans, carrots and peas, 3 years; beets, pumpkins, squash, tomatoes and watermelon, 4 years; broccoli, cabbage, cucumbers, lettuce, melons, radish and spinach, 5 years. Colorado State adds parsnip and parsley to the 1-year group. Tables from different universities disagree by a year or so for some crops, so treat these as rough guides, not expiration dates.
Old seed rarely fails all at once. Germination drops gradually: fewer seeds come up, they come up more slowly, and the seedlings can be weaker. A packet past its typical lifespan may still sprout well, and a fresh packet stored in a hot shed may not. That's why a quick test beats guessing from the date.
The paper towel test
The test takes about 10 minutes of work. Illinois Extension's method: place 10 seeds on a moist paper towel, fold it over, and seal it in a labeled plastic bag. Keep it somewhere around 70°F, such as the top of the refrigerator. Check every couple of days and keep the towel damp. Many seeds sprout within 7 to 10 days; Utah State notes peppers can take 10 to 14, so give slow crops the time on the packet before giving up. Count the seeds that sprouted: 8 out of 10 is 80% germination. Illinois suggests sowing a little heavier than normal at 70 to 90%, and buying new seed below about 50 to 60%. If you have plenty of seed, testing 20 or more gives a more reliable number.
Storing seed so it lasts
Heat and moisture age seed fastest. Store packets cool, dry and dark. A rule of thumb from Illinois: the temperature in °F plus the percent relative humidity should add up to less than 100. A sealed glass jar in the refrigerator, around 40°F, meets that easily. Make sure the container is airtight, since a refrigerator is humid inside, and keep seed away from ripening fruit, whose ethylene gas can hurt germination. A packet of silica gel in the jar helps keep the air dry. Avoid garages, sheds and sunny windowsills, where summer heat shortens seed life.
Keeping track
Writing the packet year down each time you buy or save seed makes this easier the next spring. The Seed inventory page on this site lets you list packets by variety and year and flags the ones getting old. Seed you can't replace, such as a family , is worth testing every year or two and growing out before it fades, so you can save fresh seed from it.
- OnionA day-length sensitive allium — plant the wrong variety for your latitude and you tend to get a handful of scallions instead of bulbs.
- ParsnipA biennial root with notoriously slow germination, sweet only after the first hard frost converts starch to sugar.
- ParsleyA biennial that gives you a year of leaves, then flowers and ends.
- CornA wind-pollinated grass that needs a block of plants, a block of nitrogen, and a block of your garden.
- PepperA tropical perennial grown as an annual — patient, slow, and particular about warmth.
- Why aren't my seeds germinating?Cold soil is the most common culprit — most vegetable seeds stall below 60°F, and old or improperly stored seed may not be viable at all.
- Why are my pepper seeds not germinating?Usually the mix is too cool, or they need more time. Pepper seed sprouts best at 80–85°F and barely at all below 60°F. At room temperature it can take 2 to 4 weeks, and hot peppers like habanero even longer. Warm the mix before you give up.
- How do I save seeds from my garden plants so they'll grow true next year?Open-pollinated and heirloom varieties come true from saved seed; hybrids do not — and after selecting and fully drying seed, cool, dark, dry storage is one of the biggest factors in how long it stays viable.
- When should I start seeds indoors?Count backward from your last frost date using the seed packet's weeks-to-transplant number — tomatoes usually go in 6–8 weeks before last frost, and peppers a little earlier, about 8–10 weeks.