Good Housekeeping advises aspiring seed savers to pour two tablespoons of powdered milk into several layers of tissue or paper towels.
Did you know that the longer you hold on to seeds, the less viable they are? Don’t fret, though—the way you store your seeds can significantly extend the seed’s lifespan. If you find yourself with seeds from your garden that you’d like to save for the next season (or even beyond that), here’s the best way you can preserve them.
How long do seeds last?
Even though seeds don’t look like they’re bursting with life yet, they actually are already alive. Even though they’re considered inactive, they are still involved in life-sustaining actions such as respiration on a much smaller scale than a growing plant. As Garden Professors explain, “a large amount of stored energy is needed to get through germination and sustain the seedling until it has its first set of true leaves and can photosynthesize on its own.” The key is to retain the health of the seed so that it can make it through this demanding process.
The viability of a seed depends on the type of seed and how it’s been stored. According to Micro Gardener, “the onion family and parsnips typically only last a year, so need to be used quickly. Whereas basil, radish, and cucumber seeds can last an average of five years.”
Herbs and vegetables vary in shelf life, but in general, seeds stored in a cool, dry place should last around three to five years before their viability begins to decline, however, if you store seeds in the fridge, they can last up to a decade.
Manufacturers will often use this information to determine what expiration date they put on the packaging of various seeds, but even if that date has passed, your seeds may still be able to germinate.
How to make seeds last longer
Heat and humidity decrease the likelihood of seeds germinating, so ensure that they are kept dry and out of direct sunlight. If your seeds did get damp, then dry them on a paper towel or newspaper before storing them.
The next step is to get an airtight container. Tightly sealed mason jars or glass containers with gasket lids are great, however, a Ziploc freezer bag will also work in a pinch. Good Housekeeping advises aspiring seed savers to pour two tablespoons of powdered milk into several layers of tissue or paper towels. If you then fold them into little pouches or packets, you can add them to the jar or bag with the seeds to absorb moisture. Old silica gel packets work well, too.
Once the seeds are sealed tight, put them in a cool, dry place until you are ready to plant them. As mentioned earlier, the refrigerator is the best place to store them. The optimal storage temperature is “40 degrees Fahrenheit or lower, but [it] should not drop into sub-freezing temperatures, as that kills some forms of the plant embryo,” according to Epic Gardening.
Once you’re ready for your seeds to become part of your garden, take them out of storage and let them warm up to room temperature before germinating or planting them.