I have germinated many hard seeds but failed with custard apple seeds. Do they lose viability if stored dry or in the refrigerator for over a month? I've tried scraping the surface, soaking, boiling, nothing seems to work. Its been over 3 months now and yet the color of the seed has also not changed. Any one has any tips?
I presume you are speaking of Paw Paw seeds? They are also called custard apple. I was given some, of these seeds and was told that they must remain "moist", as they were within the "pulp" of the fruit, otherwise they will not germinate. I planted them directly into my garden in the fall, I will check for germination in the summer.
I FOUND THIS INFO ON LINE:
Propagation by Seed
Pawpaw seed is slow to germinate, but germination
is not difficult if certain precautions are followed. Do
not allow the seed to dry out, because this
eventually destroys the immature dormant embryo.
To break dormancy, the seed must receive a period
of cold temperatures (termed “stratification”) lasting
90 to 120 days.
Stratification may be accomplished by sowing the
seed outdoors in the garden bed in the fall and
letting the seed overwinter there; the seed will
germinate the following year in late July or August.
Or the seed may be stratified in the refrigerator at
32-40°F (0-5°C). The seed should be stored in
plastic bags containing slightly moistened sphagnum
moss to keep the seed moist and to suppress fungal/
bacterial growth. After 90-120 days, the seed should
be removed from the refrigerator and sown in a well aerated
soil mix of pH 5.5-7.0 with an optimum
temperature of 75-85°F (25-30°C). On average the
root will emerge from the seed coat after 18 to 24
days, develop into a taproot about 10 inches (32cm)
long, and then send up a shoot after 50-60 days.
Germination is “hypogeal,” meaning that the shoot
emerges without cotyledons.
MORE GERMINATION INFO:
Gather the seeds from a ripe pawpaw fruit in autumn once the skin is solid light-green and the flesh yields to slight pressure. Slice the fruit in half, and pop out the dark brown, bean-shaped seeds with a spoon or the tip of your knife.
Place the seeds in a colander, and run water over them until all of the creamy, sticky fruit pulp has washed away. Dry the seeds on a dishcloth or paper towel.
Store the pawpaw seeds inside a paper bag away from heat and humidity until late winter, approximately two months before the last frost. Inspect the seeds, and discard any that appear damaged or rotten.
Put 2 cups of moistened sphagnum moss into a plastic freezer bag. Nestle the pawpaw seeds into the sphagnum moss so they are completely surrounded by the moist medium. Close the bag.
Store the bag in the vegetable drawer of a refrigerator for two to four months to cold stratify the pawpaw seeds. Mist the sphagnum whenever it feels slightly dried out.
Prepare a planter for each pawpaw seed after the chilling period has ended. Fill 2-gallon nursery containers with a mix of standard potting soil and 3 to 4 tablespoons of soil taken from the parent tree's growing site.
Poke a 3/4-inch-deep hole in the soil mixture. Place the pawpaw seed in the hole lengthwise. Bury it with loose soil. Pour water into each pot to distribute the beneficial microbes from the growing-site soil throughout the mix.
Place the potted pawpaw seed indoors near a window, or outdoors in a cold frame or on a lightly shaded porch. Choose a spot with at least six hours of direct sunlight daily.
Set the pots on a propagation mat to promote faster germination if daytime temperatures are well below 70 degrees F. Set the temperature to between 70 and 85 degrees F. Do not lower the temperature at night.
Check the soil moisture level daily to ensure the top inch stays moist at all times. Drizzle water onto the soil whenever the surface dries out. Add water until the top 1/2 inch feels fairly saturated.
Watch for a single stem sprout in midsummer approximately two months after sowing. Transplant the pawpaw seedling into a bed with full or partial sun and moist, acidic soil. Space multiple trees at least 15 feet apart.