Before tossing away old seed or ordering new seeds from your favorite seed catalog you should test the older seeds you have to save you a bit of time and money. Testing older seed germination rates can save you from wasting time, seed starting soil and supplies on seeds that may not sprout. A seed germination test is really simple and can be done by any home gardener with items you already have around the home. Do this seed viability test at home before planting your older seeds.
How-to Test Older Seed Germination
All you need is older seed or seed that you are unsure of, a plastic sandwich bag, a paper towel or coffee filter. For this seed experiment I decided to test some Royal Burgundy bush beans I had from Botanical Interests that were packaged for 2009.
1. Place 10 old seeds on top of a paper towel.
2. Fold the paper towel and cover the seeds.
3. Place the seeds and paper towel into the plastic sandwich bag.
4. Moistened the paper towel, seal the plastic sandwich bag and place it in a warm location.
The whole thing is then placed in a warm location, at this point make a note somewhere of when you started the germination test. Either write the date on the plastic baggie or in your garden journal. Within a week most seeds inside the dampened paper towel will begin to sprout.
10 sprouted seeds = 100% Perfect
9 sprouted seeds = 90% Excellent
8 sprouted seeds = 80% Good
6-7 sprouted seeds = 60-70% Fair
5 sprouted seeds = 50% Poor
Seeds that fall into the 60-70% germination I would sow heavier than normal. Some gardeners would probably recommend not bothering to plant seeds that germinate at 50% or lower rates. Instead of discarding these older seeds I would either sow them really heavily or direct sow them in the garden and not get my hopes up too high.
Troubleshooting Old Seed Germination
If none of your seeds are germinating move them to a warmer location like next to a heating vent or on top of the refrigerator. Some seeds may take more than a week to germinate so be patient. Parsley, celery, carrots sprout slower than beans and radishes. Don’t place the baggie in direct sunlight to prevent your seeds from being cooked. If the baggie becomes too wet open it up for a few hours to allow it to dry out some. Don’t cramp your seeds on the paper towel, seeds that don’t germinate may start to mold and infect seeds they’re touching. If the paper towel begins to mold toss it all out and start over.
Get into the habit of conducting seed germination tests on seeds that you’ve had for a while in your seed stash. Even seeds that have been properly stored in a homemade seed bank or are part of a seed library should be tested periodically. If you come across old seeds at a seed swap don’t be afraid of taking those home. This easy-to-do germination test will tell you whether they’re worth planting within a couple of days. Use the seed search engine to find quality information on everything related to gardening with seeds.