OTHER AREAS FOR RESEARCH
Potassium nitrate (KNO3) is often used to stimulate germination of dormant or irregular seeds. It can replace the light requirement of some pines. The seeds are soaked in a 1000 to 3000ppm solution (1 - 3 grams per liter), or are germinated on pads soaked in this solution. Concentration is not crucial, so 1/4 to 1/2 teaspoon per quart is fine. It is about 6 grams per teaspoon. In our tests, some seeds which normally give seedlings over 3 months have all come up in a month with KNO3.
Hydrogen peroxide stimulates many species. Seeds are soaked in a 1 - 3% solution for 5 minutes to 48 hours for hard seeds. We have had very good results.
Presoaking seeds in malt extract solution or in beer may increase germination and vigor, especially of old seeds, due to enzyme enrichment. Higher resistance to damping off and higher yields have been reported. Other sources of enzymes include digestive aids (bromelain, papain, etc, available at health food stores), enzyme cleaners for contact lenses, and enzyme drain-cleaning products.
Citric acid is available in the canning section of the grocery, and has been used at 1000ppm to stimulate the germination of some species.
Sodium hypochlorite (household bleach) has been used in a 1% solution for a one-hour presoak to stimulate germination of some species. Mix one part bleach with 4 1/4 parts water for a 1% solution. A ten minute soak in one part bleach plus one part water is an FDA approved seed disinfectant.
Smoke and charred-wood leachate (water in which charred wood has been soaked) may stimulate germination of plants from fire-prone habitats with hot, dry summers, such as the Mediterranean, California, South Africa and Australia. For a list of genera that have responded to smoke treatment, click here: Smoke Genera.