Pawpaw Seed Germiation

It has been almost a month since I put all my pawpaw seeds in tree pots with soil.  Although they were all placed in the tree pots at the same time, they were not taken out of cold storage at the same time.  The seeds were in cold storage anywhere from 75 to 90 days.  The first seeds to germinate were the ones removed from cold storage first.  However these seeds seem a little sluggish to germinate.  Five days after the first set of seeds started to germinate, the seeds that were left in the refrigerator for the full 90 days started to burst forth.  Now the 90-day seeds seem to have out-germinated the 75 day seeds.  This leads me to conclude that the key factor to germination speed is cold storage.  The longer the seeds are in cold storage, the faster they seem to germinate (up to a point).  Of course I do not advocate leaving seeds in the refrigerator for 5 years to speed up the germination process.

Additionally, the 90-day seeds seemed to have germinated well even though the seed coat was left intact.  I don't know how crucial the removal of the seed coat is to germination.  I think a properly stratified seed with optimal environmental conditions will germinate just fine with or without the seed coat.  I may do some experiments next year with seed coat v.s. Non seed coat germination.  But I believe I will leave most of the seed coats on for next year's germination.

In summary, thus far my best practices for asimina triloba seed germination are as follows.

1. Immediately clean seeds removed from fruit.

2. Immediately wrap seeds in moist paper towel.

3. Double-bag seeds/paper towel in plastic food storage bag to conserve moisture.

4.  Leave seeds in refrigerator for 90 days minimum, changing the paper towel every few weeks to prevent mold and fungus.

5.  Place seeds in 10-inch tree pots containing moist soil.

6.  Keep tree pots in a plastic tote with lid to increase moisture and humidity.