Treatments to Overcome Seed Dormancy


Softening seed coats and other coverings (Scarification)


Mechanical Scarification


Sandpaper, hammer, knife, tumbler.


Hot Water Scarification


Drop into hot water (77 to 100oC), remove from heat, allow to cool and soak for 24 hours.


Acid Scarification


Seeds, in small batches, are brought into contact with 93% Technical Grade sulphuric acid.  At the end of a set period of time (from as little as a minute to as much as an hour and a half), seeds are rinsed and acid is neutralized with baking soda.  Initially shiny seed coats would appear dull after this treatment.


Warm Moist Scarification


Keep plants in warm moist soil or unsterilized sand for several months to soften seed coats through microbial activity.  Seeds may also be planted directly in the summer or fall while soil temperatures are warm.




Refrigerated Stratification


Stratification is accomplished by placing seeds in moist planting medium in a cold environment for a period of time (two weeks to three months).  Seeds require moisture, cold and oxygen.  In general, this period of time allows an undeveloped embryo to mature.


Outdoor  Stratification


Seeds may be kept outdoors through the winter in lined pits or raised beds.  They must be protected from freezing, drying and rodent predation (use wire netting in the soil).  Pits or beds are layered with clean sand, medium with seeds, more clean sand, etc.



Outdoor Planting


Some categories of seeds may simply be planted outdoors in the fall and natural stratification is allowed to happen.





Inhibitors in seed coat


Leaching simply requires washing seeds with fresh water.  It may be accomplished by running water over seeds in a container (mason jar) for 12 to 48 hours.  For longer washing, and for seeds that produce a large amount of soluble substances, water should be changed every 12 hours, or seeds should be washed in running water.  If you use running water or a bubbler, foam may be produced; either use cheesecloth to prevent seeds from being carried out of the jar, or sit the jar in a pan.


Inhibitors in pulp


Some chemical inhibitors are found in the pulp of fleshy fruit.  Pulp should be removed by soaking or maceration; seeds should then be washed.



Laboratory Treatments




Store imbibed seeds at 5 to 10oC for five to seven days before attempting germination.




Subject dried seeds to 37 to 40oC for five to seven days prior to germination.


Alternating Temperatures


Use daily alternation of temperatures , going from 15-20oC to 30oC, with seeds held out the lower temperature for 16 hours and the higher temperature for 8 hours.


Light Exposure


Light should be provided by cool-white fluorescent lamps, at high intensity, for at least eight hours daily.  Seeds should be imbibed and placed on tip of the medium.


Potassium Nitrate


Moisten substratum with 0.1 to 0.2 percent potassium nitrate solution.




Soak in gibberellic acid or cytokinin (kinetin) solution.  Twelve to 24 hour soak is recommended.  Concentrations vary.