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Ask Extension: How do I know if my old seed packets are any good?

Photo: Julie Weisenhorn, UMN Extension
Q: I have a number of seed packets (annual flowers and easy vegetables) that are partially full but are out of date. Is there a way to predict what percentage of seeds will sprout? Or should I just toss them in the compost and buy fresh seeds?

A: Seed viability period can vary depending on the plant, how the seeds are stored and even on their treatment (pelletized, etc.) prior to packaging. Ideally, they should be stored in well sealed, water-tight containers in a cool (50 degrees F.), dark location. If you have not stored them like this, you might want to consider buying new seeds.

You can test the seeds yourself by using what's called the "ragdoll method," an inexpensive and easy way to test seed viability. In fact, we have a how-to video that can walk you through the steps, and it's a great activity to do with kids! 

It's also a good way to start warm season plants like tomatoes and peppers. 

How to do the 'Ragdoll Method' of testing seeds

Grab your seeds and these materials, watch the video below, then come back to this article to learn how viable your seeds are: 
  • Sheet of damp paper towel
  • Sealable plastic quart bag
  • Seeds of your choice
  • Marking pen

How to judge the success of your seeds

At the end of the germination period, count the number of seeds that have germinated and divide that number by the number of seeds you used for the test. 
  • Same or close to same germination rate indicated on the seed package: GOOD
  • Rate less than 75%: BAD--you are better off buying new seeds
  • If the rate is between 75% and 90%: Use more than 3-4 seeds per planting spot. You can always thin the sprouts to one seedling after germination to get the plants you want for your garden.
Red pepper seeds 8 days later.
Photo: Julie Weisenhorn, UMN Extension

What to do next  

Pepper seeds, 8 days later: The first root has emerged from some of the seeds. 

Here's what to do next: 

  • Gently remove and plant in potting soil. 
  • Place in a warm sunny window or under grow lights. 
  • Keep the soil moist (not wet). It should feel like a damp sponge when you touch it. 

These pepper plants should be large enough to plant in a large pot or a sunny garden location by end of May or early June.

Read this Extension article to learn how to plant your seeds, harden off the seedlings and plant them in your garden.
Starting seeds indoors

Author: Julie Weisenhorn, Extension Educator, Gail Hudson, Y&G News Editor



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