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How To Test The Germination Rate of Old Seeds

If you’ve collected seeds over the years, you know their germination rate begins to fall as they get older. Here is how to test the germination rate of old seeds so you don’t waste your time planting duds.

As the days get longer and the nights get warmer, everyone starts thinking about Spring.

how to test the germination rate of old seeds

Farmers and gardeners start dreaming about the smell of the soil, watching their plants flourish, and feeling the hot summer sun on their backs.

One of the first steps for planning your summer garden is to know where you are now.

When you begin planning what you’ll grow this year, you’ll need to take an inventory of the seeds you already have.

If you have leftovers from years prior, or seeds collected from last year’s harvest, you need to test how many seeds are still good.

There’s nothing worse than planting, nurturing and caring for a seed, only to have nothing happen!

As time goes on, seeds lose their viability.

The rate and ratio, however, that they lose their viability all depends on the quality of seed and how they were stored.

baby helping test old seeds
baby helping with seeds

Ideally, you will be able to save your seeds in mason jars, or food-grade storage bags in the fridge. Whatever container you use, seeds will do better in cool, dark, dry places.

I save my seeds in small mason jars or baby-food containers in a closed draw in the hutch of my dining room.

**Bonus: larger seeds act like a rattle and are super fun to shake for little hands**

I also make sure to cut out the seed info from the packet and keep it with the seeds, just in case a label rips off the jars, or I want to remember what company I bought them from.

seed storage
seed storage

how to Test the germination rate of old Seeds

To test your seeds, dampen a paper towel. You want it moist, but not soggy. Then, line up your seeds along one edge of the paper towel.

testing seeds with a wet paper towel
testing seeds

Once your seeds are lined up on your damp paper towel, roll them up length-wise. This mimics soil. Your seeds will be kept damp and protected from sunlight wrapped in the paper towel.

leave seeds wrapped in a wet paper towel in a freezer bag to test germination rate
testing seeds

Now that you have your cigar of seeds and paper towel, throw it in a freezer bag, or mason jar.

You want to keep the paper towel (and seeds) damp, but not soggy. Keeping them in a freezer bag or mason jar will prevent them from drying out.

Label them with the type of seed and year of the seed so you know what you have when they germinate.

Store them in a warm, dark place. Every few days, open the container and check the seeds.

Depending on the type of seed you’re testing, it could take 2 days to 2 weeks before you’ll see any change.

While you’re checking them, spritz them with water if the paper towel starts to dry out.

Once your seeds begin to germinate, you can transplant them to seed starting trays.

Check out my post on how I start seeds indoors.

If you need to buy more seeds, check out Seeds for Generations. They’re a small, family-run seed company, so go show them some love!

For more vegetable gardening info, check out my 30 second guides to growing vegetables.

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