Apple seeds carry a unique genetic combination from two parent trees, resulting from sexual reproduction. Saving these seeds is the first step toward growing a new apple tree. Unlike many common garden seeds, apple seeds possess a natural defense mechanism called dormancy. This biological state prevents the embryo from sprouting at the wrong time of year, necessitating a period of artificial winter conditions before they are ready for successful planting.
Preparing Seeds for Storage
After separating the seeds from the core, clean them thoroughly. Remaining fruit pulp contains sugars that attract mold or fungus during storage, compromising the seed’s viability. Rinsing the seeds under clean water removes this residue. Some growers opt for a brief soak in a mild solution of hydrogen peroxide or diluted bleach to sterilize the seed coat against fungal spores.
Following cleaning, the seeds must be air-dried for a short period. This initial drying allows surface moisture to evaporate, preventing immediate mold growth in storage. Avoid complete dehydration, as the embryo inside must retain moisture to remain viable. Rely on a cool, dry location for about one to two days, avoiding any artificial heat source which can irreparably damage the internal embryo.
Why Apple Seeds Require Cold Stratification
Seed dormancy is a survival mechanism common in plants from temperate climates. This mechanism ensures that seeds do not germinate in the autumn when a newly sprouted seedling would face winter frost. The seed is biologically programmed to delay germination until it detects that a full cold season has passed.
The process of breaking this dormancy is called stratification, which involves exposing the seeds to sustained cold and moisture. This extended cold period triggers a series of chemical changes that neutralize germination-inhibiting compounds. Once the seed has accumulated the required chilling hours, the embryo receives the internal signal that spring has arrived, making it safe to sprout and begin growth. If the seeds are planted without this chilling period, they will fail to germinate entirely or exhibit very poor and erratic sprouting rates.
Step-by-Step Cold Storage Method
Moist-cold stratification requires providing the seeds with consistent cold and moisture. This process typically requires a minimum of 60 to 90 days, though some varieties may benefit from up to 14 weeks of chilling. The temperature must be maintained just above freezing, with an optimal range between 35 and 40 degrees Fahrenheit.
Begin by selecting a medium to hold the moisture:
- Slightly dampened peat moss
- Fine sand
- Paper towels
The medium should be moist but not saturated, as excess water can promote mold growth or deprive the seeds of necessary oxygen. A good test is to squeeze the material; only a few drops of water should come out.
Next, mix the cleaned and dried seeds with the chosen damp medium inside a container, such as a resealable plastic bag or a small airtight plastic container. Label the container with the apple variety and the date it was placed into storage to track the duration of the stratification period. The sealed container is then placed in the back of a refrigerator, which typically maintains the most consistent and appropriate temperature for chilling.
Periodically check the contents of the bag for any signs of mold growth. If mold is present, the seeds should be rinsed and placed into a fresh, slightly less damp medium. After about 60 days, you may also begin to see some seeds prematurely sprouting. These seeds should be removed and planted immediately, as they are ready to grow and will not survive long in the cold environment once they have broken dormancy.