Stratification is the name given to the process of inducing seeds to emerge from dormancy through cold treatment.
A cold treatment. Stratification is the name given to the process of inducing seeds to emerge from dormancy through cold treatment. To stratify, soak the seeds for up to 24 hours and combine them with a mix of moist peat and sand in a plastic bag. Place the mixture in the refrigerator and keep at a temperature of 1° to 5°C (34°-41°F) for 4 to 12 weeks.
Scarification. Some seeds have hard coverings that must be penetrated before they will germinate. This treatment — called scarification — can be done in one of two ways, depending on the size of the seed. Large seeds can be nicked with a sharp file or rubbed with a fine sandpaper or an emery board until the coat is broken; this is where the new sprout will start.
Seeds too small to nick are soaked overnight in a hot-water bath. Place seeds in a container and pour water heated to about 88°C (190°F) over them, in a water-to-seed ratio of 6:1. After 24 hours, remove and sow immediately without drying.
Good old seed. To test old seed for viability, pour it into a glass of water. Seeds that fall to the bottom have a good chance of growing. Discard those that float to the top.
Another test. Place 30-odd seeds left over from last year's packet between two moist paper towels for a few days. Remoisten the towels often and lift a corner to check for germination. Use the percentage of germinated seed as a guide for how much to sow.
Nice and cozy. The tops of water heaters or refrigerators make a perfect place to set a seed flat if their temperature matches that needed for germination — 24°C (75°F) for asparagus, lettuce, and peas, for example.
Treat seeds for fungus. To protect gathered seeds from many fungal and bacterial diseases, soak them in hot water (52°C [125°F]) for 30 minutes. Coating seeds with a small amount of fungicide, like captan, helps deter damping off.
Be crafty. Garden seed that is no longer viable can be used to make mosaic patterns, suitable for jewelry and pictures. Use white glue to affix the seeds and cover with a coating of clear shellac. Choose large and small seeds with colorful shapes and patterns, including corn and beans.
Stratification and scarification make it possible to speed the germination of certain seeds.
Seeds to stratify
Seeds to scarify