How to Test Seeds For Germination (Paper Towel Test)

Want to know if seeds will germinate without going to the trouble of sowing them? This easy paper towel test shows which seeds will sprout and along with the expected germination rates.

For seed starting instructions also see Seed Starting For Beginners: Sow Inside Grow Outside which shares all of my tips for indoor seed sowing.

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Test Seeds Before Sowing

If you have ever sown a bunch of flower or vegetable seeds in the garden or containers only to watch and wait for weeks to find nothing sprouted, it’s a big disappointment and a lot of valuable growing time wasted.

For those of us in cold climates, those days between last frost in spring and first frost in fall are prime growing days and not to be squandered on bad seeds.

Viability: the ability of seeds to germinate

Most seeds stay viable for at least a year. From there, it varies greatly.

We know a lot about the best way to store seeds at home but you can never really know if they are viable unless you try growing them.

Germination: the beginning of growth of a seed, spore, or bud

While it is an extra step, a germination test takes out the guesswork.

Not only will you learn whether or not the seeds will sprout, but you can also find out your germination rate. This tells you what percentage of your seeds are viable, which in turn lets you know how many to sow to end up with the quantity of plants you want.

How long does it take to test seeds?

How long a germination test takes depends on the type of seed. You can’t hurry a seed to sprout but you can provide optimum conditions which ensure it happens as soon as possible.

One of the biggest misconceptions about germination tests is thinking it somehow fast-tracks the process. It does not. Seeds can only sprout as fast as they can sprout. But the advantage is knowing the status of the seeds ahead of the growing season.

The test is done at home and does not require soil or other growing medium, just household supplies.

For most seeds you’ll have an answer in 10-14 days. On the quick end, radishes sprout within days, while peppers can take weeks, and something like clematis can take a year or more.

The method shown below is manual. You can also try using your Instant Pot (Amazon) or slow cooker using these instructions.

I like to test most seeds in early spring, a number of weeks before last frost, so I have answers before it’s time to direct sow crops outdoors.

This way, if I’ve got some duds, there is still time to order fresh seeds.

You may have heard of the seed float test, which sounds very quick and easy, but unfortunately it’s not reliable. You can read more about it in the Frequently Asked Questions section.

Of all the testing methods suggested online, the paper towel method is the easiest and most reliable. I’ve provided complete step-by-step instructions below.

Contents

• How To Test Seeds
• Frequently Asked Questions
• Resources

How To Test Seeds

Get Ready

For seed tests, just like regular seed sowing, you will need to follow the advice on your seed packet regarding any necessary preparations. If you’re new to sowing, this article on how to read seed packets is helpful.

Dormant: not active or growing, but having the ability to be active at a later time

Dormant seeds start growing when their conditions change.

For many seeds this means taking the dry, viable seeds from storage and exposing them to moisture, warmth, and oxygen. Most do not require light until they have sprouted.

Some seeds have additional needs prior to germination that will be noted on the seed packet.

• Scarification means you need to nick the seed coat to allow water and oxygen to reach the embryo inside. Generally this is done with a nail file or sandpaper—just enough to make the coat penetrable without causing any other damage. Soaking seeds in water is another approach.
• Stratification is where we expose the seeds to cold and (usually) moisture to mimic winter conditions the plant has evolved with.

But, as mentioned, most seeds are ready to test right out of the packet.

If your seeds do sprout during the test, you can continue growing them if you like.

Supplies

• Paper towel (or paper coffee filter or cotton tea towel)
• Seeds
• Container (food storage container, glass, or plastic) or plastic food bag
• Marking pen (or some way of labelling your test)
• Plant water mister
• Heat mat with thermostat (optional)

Steps

• If you want to test several types of seeds at once, use a separate paper towel for each group.
• Always wash your hands before handling seeds and seed sowing supplies.
• Do any required preparations listed on your seed packet like scarification or stratification prior to your test.

1. Label the container (or bag) with the name of the seeds or keep notes.

2. Moisten a sheet of paper towel with warm water (room temperature or warmer). The paper towel should be moist but not drip water when squeezed in a ball.

3. Place at least 10 seeds on one half of the paper towel. If the seeds are tiny, you may find it easier to use tweezers or the moistened tip of a dibber to set them in place.

4. Fold over the paper towel to cover seeds and place everything in an open food storage container or bag (allowing for air circulation). Make sure the moisture is reaching the entire exterior of the seeds.

5. Place your container in dark, warm cupboard or similar location.

Check your seed packet for the expected number of days to germinate so you know how long this should take. Allow extra time if conditions are not optimum.

6. Set a reminder in your phone or calendar to check your seeds every day or two. Your job is to make sure the paper towel never gets dry. You can spritz it with warm water as needed, always making sure the seeds are kept moist.

7. After days or weeks, depending on the type of seeds and temperature, you may start seeing signs of sprouting. Some seeds within the same batch may start sooner than others. This is yet another smart survival tactic. Take pictures to compare your seeds one day to the next.

8. When you feel you have given the test enough time—at least as long as the expected number of days to germinate with some elbow room, you can do your assessment.

• Seeds sprouted = they are viable.
• How many sprouted = your germination rate.
  
  For example, if 8 out of 10 germinated, that’s an 80% germination rate.
  
  Because this is such a small sample size, your actual germination rate be higher or lower but you have a ballpark number.
  
  A good sample size would be 100 seeds or more but most of us don’t want to use up that many seeds just to find out.
  
  If you are concerned about quantities for the garden, always sow extra for insurance.

More Ways To Use This Test

You can also use this germination test to both test and grow various fruit seeds from kitchen scraps including:

• Apple
• Avocado
• Citrus fruits including lemon, orange, and grapefruit
• Mango
• Peaches and plums

I much prefer testing first so I don’t bother planting in soil unless I know the seed is viable.

Frequently Asked Questions

Resources

Read More

• Best Soil Temperatures for Flower Seeds
• Best Soil Temperatures for Vegetable Seeds
• Seed Sowing For Beginners: Sow Inside Grow Outside
• Trick for Germinating Stubborn Delphinium Seeds
• 10 Easy Ways to Cut Costs on Garden Seeds
• Seed Viability Chart: How Long Seeds Last in Storage

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~Melissa the Empress of Dirt ♛