Seed Germination Testing

Seed Germination Testing

By Cynthia Averett, VINES Urban Farm Manager


Do you have seeds left over from last year, maybe even 2 or 3 years ago? If you use these seeds, will they still germinate, or will you have a failed planting if you use them?

All seeds have different shelf lives – some seeds, if stored properly, will last years. Others may only be good for one season. Here is a simple chart to give you an idea of how long some seeds will store.

Regardless of how long this chart says you can store a seed, it depends on a lot of factors, like how well they are stored. If you want to use old seed, you can do a simple germination test to see how viable your seeds are.

Simply wet a paper towel,and place 10 seeds of the variety you are testing in the paper towel. Fold the paper towel over the seeds, and place the paper towel in a plastic bag. Make sure to label the bag with what seed you are testing, and the date, so you don’t forget what you are testing.

Place the bag in a warm spot, like on the top of your fridge. After a day or two, check on the seeds to see if they have begun to germinate. Keep checking daily – remember, different seeds take different times to germinate: things like kale and lettuce should germinate in just a few days, while other seeds like carrots and parsnips may take a week or two.

The reason it helps to use 10 seeds is that you can easily figure out the “germination rate” of your seeds. If you don’t see any germination after 2 weeks, you have a 0% germination rate, and you will need to replace those seeds. If 5 out of 10 germinate, that is a 50% germination rate, which means about half your seed is good. You can still plant, but you will not get good germination, and you probably want to consider replacing them. If 9 out of 10 germinate, that’s a 90% germination rate, and your seed is still good to use (remember, not even seeds straight from the supplier have a 100% germination rate).

We all want to avoid waste as much as possible, and it can be very sad to get rid of old seed! It is important to try to buy just what you need, but if you do end up with more seed you can use, make sure you store it in a dry, cool, and dark place in between seasons, and try out this germination test to see if it can be used again! Often if I have old seed, instead of throwing it away, I will toss it in an unused part of my garden – if it germinates, great! If not, at least you tried! Happy seeding!