Have you ever been spring cleaning and came across an old packet of planting seeds that you forgot about? Or perhaps you found a good sale on seeds at the end of the planting season and want to know if they can be saved for planting next year. Many gardeners would like a way to determine if these seeds are still capable of growing if planted. APRD’s Urban Forestry Land Manager Wendy Pappas offers this advice to help you determine if your seeds are still good before you plant them!

The Paper Towel Test

One method of testing the growing capability of seeds is to use the paper towel test. This test works on a wide variety of vegetables, herbs, and flowers. This can be done by taking a regular paper towel and running it under water, or laying the paper towel flat and misting with water. Either way, the paper towel does not need to be dripping wet.

Place your seeds in the middle of the flat, moist paper towel and fold it into a square so that the wet paper towel is both under and over the seeds. It should look like a small moist square. Then, place this square paper towel in a zip baggy and seal it tight to keep it from drying out.

Place the baggy in a warm area inside your house where it can maintain a temperature of at least 75 degrees. If you are testing multiple types of seeds, it’s a good idea to label your bags so you can tell them apart. Once they are all bagged up, simply wait several days to a week to see if the seeds germinate. Different types of seeds will have different germination windows, so this will determine how long it should take to expect results depending on which seeds you are testing.

How to Tell if Seeds are Germinating

If you are testing seeds that came out of a package, you can likely find the germination window listed on the package and wait approximately that long to check for germination. If the seeds came from elsewhere or you no longer have the package, you can still use some observations to determine if the seeds are in the germinating process.

Seeds should start to swell when beginning to germinate. If you wait several weeks and no swelling has occurred, the seeds are most likely past their prime and will not grow if planted. You can also note the germination rate of your seeds as an indicator of their growth viability. If you tested 10 seeds in your paper towel and 8 of them germinate, you have a germination rate of 80% which means your seeds are in good shape and can be planted. If only 3 out of 10 germinate, your germination rate is only 30% and these seeds are likely not capable of growing well. It’s a good idea to go ahead and replace seeds if they have a germination rate of 50% or less.

Of course, if you just like to have fun in your garden and you aren’t relying on your garden as a food source, you can always throw any old seeds in the soil and see what happens! Make sure to at least know the type of seeds you are planting so you know when to expect germination. We hope these tips are helpful in your gardening practice and can be used for seasons to come when you come across those old seeds laying around. As always, happy gardening from APRD!