Shortly after filling my self-made planter,
(yes, I built it, but I didn’t cut the lumber) with organic potting mix, I found several packets of seeds that had expired several years ago. I decide to do a little experiment and scattered the mesclun seeds on one side and the arugula seeds on the other. A few days later my container was a giant chia pet, with barely any visible soil.
Expecting a germination rate of less than 25%, I was shocked at how many seeds were still viable. The seeds had been stored in a cool dry place inside their original unopened packets, placed in a freezer bag.
We have been eating sprouts and thinnings for a few weeks and the plants are finally approaching their mature size. Normally my plant rows are more even, but I wasn’t expecting to thin-out 50-60 little seedlings.
The moral of the story: Test your expired seed packets before you toss them, unless they have been stored improperly. What is improper? If the packets have been left in a very hot environment, become wet or both, then it is unlikely they will germinate.
I don’t recommend using your garden beds or containers to test your seeds, unless you have a large yard. The easiest way to test the germination rate of your seeds: THE PLASTIC BAG METHOD
- Dampen a paper towel and ring it out if necessary. You do not want it to be soaking wet.
- Lay the single or double layer of damp paper towels flat in a standard 1 gallon freezer bag.
- Next count out ten seeds from each packet and place each seed evenly apart on the paper towel, leaving a large space between sections for each packet. You may label the sections using post-its or a sharpie if you are testing more than a few packets at a time. Seal the bag, pushing out most of the air.
- Place the bag on a flat surface in the warmest room of your home or near a warm, heat generating appliance (top of the refrigerator, near a printer, DVR or cable box). The bag creates a mini-greehouse and many be reused indefinitely for this purpose— unless you forget about your germinating seeds and the bag becomes moldy.
- Check the seeds every 1-2 days to ensure there is moisture in your bag and to see if the seeds are germinating. Use the number of days for germination on the seed packet as your guide.
- Once the seeds have sprouted, count how many of the seeds have germinated from each group.
- Since we are using 10 seeds this makes calculating the germination rate easy.
- 1 out of 10 seeds = 10% germination rate vs 9 out of 10 seeds = 90% germination rate
If the seeds are going to be used to grow plants as opposed to eating or growing sprouts, it is safe to use them past the expiration date. This is a small way to reduce waste and save money. Start with small changes to make sustainability part of your life.