How to Tell If Seeds Are Good

Before you get your hands dirty and start planting, it’s a good idea to find out if your seeds are actually still good. Whether you’ve got leftover seeds from last year (or the last ten), figuring out their viability can save you time, effort, and garden space. I have a simple test for you to use to tell if your seeds are good or bad.

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It’s Not You, It’s Them

Sometimes seeds just aren’t good anymore, and it has nothing to do with how you planted them—trust me, even seasoned gardeners get caught off guard and feel discouraged when nothing sprouts, thinking they messed up.

Let’s go over a few simple ways to test for viable seeds, how to spot duds, and what to expect from older packets.

What Are Viable Seeds?

When we talk about viable seeds, we’re talking about seeds that are still capable of growing into healthy plants. Not every seed will sprout—even if it looks perfectly fine on the outside. Over time, seeds can dry out too much or lose their ability to germinate, especially if they’ve been stored in poor conditions.

If you’ve ever wondered whether those old packets tucked in the back of a drawer are still worth planting, you’re not alone. The good news? There are a couple of super-easy ways to check if your seeds are still good.

But first, if you’re unsure what the seed packet is telling you (like the seed date, germination rate, or planting zone info), make sure to read my article on How to Read a Seed Packet so you’re starting with all the right info.

How Do You Tell If Your Seeds Are Good or Bad?

The easiest way to tell if a seed is still good is to test how well it germinates. You can’t always tell by just looking at it—although shriveled, cracked, or moldy seeds are a pretty clear “nope.”

A quick at-home germination test is one of the best ways to find out. All you need is a paper towel, a plastic bag, and a few days of patience.

How to Do a Seed Germination Paper Towel Test

This is my go-to method for checking if old seeds are still worth planting. It’s simple and uses supplies you already have on hand.

Step-by-step to test if seeds are good:

1. Dampen a paper towel—just enough water so it’s moist, not dripping.
2. Place 5–10 seeds in a row on the towel.
3. Fold it over to cover the seeds and place the towel in a zip-top bag.
4. Label it with the seed type and date.
5. Keep the bag in a warm area (like on top of the fridge or a sunny windowsill).
6. Check in a few days and again around day 10.
7. Your seeds are good if they sprout a little tail, like in the picture above. If they didn’t grow, they are bad.
   

To figure out the germination rate, just divide the number of seeds that sprouted by the number you tested—so if 9 out of 10 sprout, you’ve got a 90% germination rate and a good batch to plant.

If most of the seeds have sprouted roots, congrats! Those are viable seeds. If only one or two sprout—or none at all—it might be time to toss the packet.

🌱 Want to give your seeds an extra head start? Check out Soaking Seeds Before Planting for Better Germination to learn when and how to soak them properly.

Do Bad Seeds Float or Sink in Water?

You may have heard that good seeds sink and bad seeds float. It’s a popular trick, and while it can be helpful in some cases, it’s not 100% reliable.

To try it:

• Place your seeds in a glass of room-temperature water.
  
• Let them sit for about 15–30 minutes.
  
• Seeds that sink are usually more viable than floaters.
  

But here’s the thing—some perfectly good seeds float just because of air pockets or how they’re shaped. So, while this test is fun and quick, I don’t rely on it alone. If you really want to know, the paper towel germination test is the better way to go.

How Do I Test If My Seeds Are Viable?

To keep it simple:

• Look at the seed packet date. Most seeds are best used within 1–2 years, but some last longer if stored well.
  
• Try the paper towel germination test. It gives you a clear idea of how many plants you’ll actually get.
  
• Use the float test if you’re curious, but don’t bet the whole garden on it.
  

Also, remember to check the back of the packet for details like the ideal planting depth and spacing. My guide on How to Read a Seed Packet walks you through all those helpful little notes most people overlook.

And if you’re not sure what will grow where you live, make sure you’ve figured out your Plant Hardiness Zone. It’s the best starting point for planting with confidence.

Are 20-Year-Old Seeds Still Good?

Surprisingly… sometimes!

It depends on the type of seed and how it was stored. Seeds like tomatoes, peppers, and beans tend to last longer than things like onions or parsnips. If they’ve been kept in a cool, dry, and dark place, you might still get a few to sprout—even after two decades.

That said, the germination rate will be much lower, so it’s especially important to test them first. If they do sprout, you’ll have a fun little garden experiment on your hands. If not, it’s probably time to replace them.

 Fun Fact: Ancient Seeds That Sprouted

• Judean Date Palm (Methuselah): A 2,000-year-old seed germinated in 2005, leading to a thriving tree that has since produced fruit.​The Jerusalem Post
  
• Sacred Lotus: Seeds approximately 1,300 years old were successfully germinated, showcasing the remarkable longevity of some plant species.

What To Do After Testing Your Seeds

Don’t let a few old seed packets go to waste without giving them a chance. A simple germination test can save you time and help you plan your garden more efficiently. Plus, it’s kind of fun to watch tiny sprouts pop out of a paper towel!

Once you’ve figured out which seeds are still good, be sure to check:

• How to Read a Seed Packet
  
• Soaking Seeds Before Planting
  
• Understanding Your Planting Zone
  

These simple steps can make all the difference when it comes to growing healthy plants that actually thrive where you live.

📝 Want a simple way to track your results? Download my free Seed Viability Tracker and keep all your testing info in one place!