If you've been gardening for a few seasons, you probably have a lot of half-used packets of seeds. Most seeds stay viable for three or four years, but their germination rates decrease over time. You can plant seeds in your garden and hope for the best, or you can germinate them so you know which ones are bad. There is no way to make a bad seed grow, so to save space in your garden you should find out if the seeds are viable.
Soak two paper towels with water and wring some of the water out. The towels should be quite wet but not dripping. Lay the towels on top of each other and fold them in half.
Put 10 seeds of one type of plant on the paper towel. Make sure there is plenty of space between the seeds. Bad seeds mold, and the mold can pass to healthy, germinating seeds and kill them.
Cover the seeds with another wet paper towel and slide them into a plastic bag. Close the bag and place the seeds somewhere safe at room temperature. Leave about 1 inch of the bag open so the seeds can get air.
Wait a week before checking the seeds for germination. Some seeds, like basil or tomatoes, might take more than a week to germinate. Give the seeds up to a week longer than their germination time listed on the packet. Old seeds usually take longer to germinate. Check the towels regularly to make sure they stay wet.
Count the seeds that have germinated to get a percentage of how many in the packet are good. For example, if nine seeds germinate, the seeds are 90 percent good and can be planted according to their instructions. If 70 percent of the seeds germinate, plant them closer together than instructed on the packet. If the germination rate is 50 percent or less, throw the seeds away or plant them very close together to make up for the bad seeds.
Plant any germinated seeds, if desired, but keep in mind that if the germination rate is low, the seeds are probably quite old. Old seeds grow more slowly and do not yield as well as fresh seeds.