Each pawpaw and persimmon season, one ends up with many seeds to process and store. My hope in this thread is that people can share best practices for efficient processing, best practices for longest possible storage of seeds, and some failures.
My method:
Collect piles of seeds from eating out of hand or from the food mill. At this stage, most of the seeds will be covered in a clinging, gooey, elastic mucilage.
Spread seeds on a plate or baking tray, and place in the fridge for a week. The mucilage will darken, toughen and dry down somewhat, but not become very dry. (Refigeration is recommended, as leaving them on the counter will attract fruit flies. Leaving them in a garage or shed, where you don‘t care about fruit flies and rodents cannot get them, is also ok.)
Under running water, gently scratch on the edge of the seed opposite from the seed eye. This will tear through the mucilage sack and let you peel it away from the seed, and tear it cleanly off of the eye.
Rinse any residual fruit and sugars on the surface of the seed.
Place seeds on paper towels to dry away surface droplets of water.
Place seeds onto fresh dry paper towels on the counter, and leave them for 6-24 hours to allow slight further drying.
Place the cleaned, slightly dried seeds into a reasealble plastic container with spanish moss or long fiber sphagnum moss. Adding a couple drops of water to the moss is ok.
Refridgerate (don‘t freeze!) the container until planting time.
My planting practice: I plant them in gang pots 30-60 days before my Zone 7 frost free date. I don‘t allow the pot to freeze.
Later on I gently separate the spouted seedlings (July or August), putting the vigorous ones into individual pots for use as grafting rootstock, over the next two years. I gang pot the „runts“ to see if any of them also thrive and individually pot any good ones later.
Some questions:
Prepared in this way, or similarly, how many years can persimmon and pawpaw seeds be kept? (The answer may differ of course for the two genera.)
Is there a more efficient way to process the seeds, (2a) for ones that will be planted as rootstock, or (2b) for those that may be sold to consumers.
Are there changes to the above method that may prolong seed viability or germination percentage?
When planting, what is the best orientation: eye downward, eye upward, or simply random orientation?
For me, persimmon seeds are not as delicate. They can handle appropriately harsh handing. This assumes that you got the fruit fresh and are processing the seeds yourself (including fruit that might have been in the fridge for a long time).
Eat or process fruit
Spit out seeds.
While the seeds are still wet, clean off completely (everything), rinse them off
Let them dry on a counter. Dry, yes dry. Seriously dry. Let me repeat dry. No, persimmon seeds don’t need to be kept damp. I’m assuming the seeds are coming directly from the fruit to being processed right away. The key is clean them and dry them the point that they won’t mold in a dry ziploc, but not overly dry. I don’t let them dry to the stage of collapsing. It’s a fine line. I don’t treat them with anything otherwise. They should keep a long time this way but I don’t know how long they remain viable.
When it’s time to stratify (I usually do this in about Feb), throw the seeds in water. I guess I usually let them soak for a couple of days.
Put in damp spagnum and throw in the fridge. I think even as short as 45 days might be enough although I usually leave for 60 days at least without them trying to germinate in the fridge. There was some research that soaking in water for a long time might possibly replace stratification (in Kaki types) but I haven’t tried that.
When planting, I just lay the seed flat on it’s side and not worry about it. Persimmon aren’t picky. Usually I get close to 100% germination.
A few years back… i ate some rich tooie (wild dv) persimmons and spit out the seeds.
It was into Oct at the time.
I took 3 of those freesh seeds with a little pulp still on them… and planted them in a 16 inch wide x 10 inch deep planter pot… about a inch deep… then covered with some fine pinebark mulch and a few leaves.
I put that planter pot in the edge of my woods and did nothing else to it all fall winter and spring.
Thanks for the beautiful pictures and story. And your sprout is so vigorous! Really lovely.
What you describe is the natural way persimmon sprouting happens: fruit gets eaten, and the seeds get dispersed and sprout, usually with their mucilage jacket.
To clarify my intent, oftentimes one has seeds, but needs to store them. The main scenario is for shipping „clean“ seeds to consumers. (They don‘t want a gooey, moldy mass.) So, how best to prepare the seeds to maximize the period of time of their viability?
The questions I hope some here will be able to answer are 1) the least labor-intensive seed preparation method and 2) how many years seeds can remain viable.
@AFFN… I have had a few board members request seeds from my sisters rich tooie persimmons (which is what I grew in the pics above).
I have sent out several hundred of those to different individuals… some were establishing persimmon orchards and were using them to produce rootstock.
The first person that asked for them… did not want clean dry persimmons seeds at all… per his research “fresh” seeds germinated better than dried seeds.
I sent him seeds packed in a little persimmon pulp. I am not sure exactly what all he did with them after receiving them… he may have cleaned them artifically stratified them… not sure… but he wanted them shipped fresh in a little pulp… and I did that… and for everyone that asked for more after that… I did them the same way.
If I ever grow more persimmon seedlings … I will eat the fruit and then plant the seeds… I know for sure that works great here.
To preserve pawpaw seed viability, they should not dry out. Inside pawpaw seeds, in contrast to other seed types, is a living embrionic plant.
You may find the germination percentage in your dry seeds is already dramatically reduced. Keeping them moist (not soaking, just moist over the winter in your fridge, is probably your best bet, then getting them into soil in early spring (I do this in March in Zone 7a, careful to never let the pot freeze.)
(I gang pot bunches of seeds (50 or so) in 12 inch or deeper pots, and then I separate the sprouts a few months later, July or August, once I see what has sprouted. With gentle handling the sprouts tolerate this to > 95%)
I got my seed from Mr. Potter and they had a silver coating on them. I followed his instructions and they all germinated and i also shared some seedlings with others on this forum.
Glad your seed endeavors worked out well. Seed are shipped moist and in time can dry out. If they are fresh and planted in a timely manner, they usually germinate well. They longer they are stored dry, the lower the germination rate. For those that have an interest, I still have pawpaw seeds available.
“Clean” seeds are required by certain customers, like state forestry agencies tasked with reforestation and seedling generation projects. They often only accept cleaned seeds, and pay for seeds per pound.
Some comsumers also “require” clean seeds, in that they are put off by the gooey mass of seeds. (Yes, this is more of a consumer “desirement” than requirement. It is what it is. We live to serve our public.)
Sometimes one wants to store seeds over multiple seasons, for example to have seedstock for sprouting rootstock annually. Not every year yields a harvest, and holding seeds in reserve bridges these gaps in harvests. Also, one may not sell out of seeds one year, but need more the next year; a customer will want to know if they are viable. Hence, my question on seed shelf life.
Keeping seeds in mucilage over months-long periods allows mold to grow. I have seen mold growth reduce germination rates appreciably, by up to 90%.
Cleaning the seeds efficiently is the problem I am seeking to solve. And storing them in a way that maximizes their shelf life. The goal is at least “three years” if possible.
The challenge is that pawpaws and persimmons do better moist, not frozen. Long term seed banks freeze many kinds of seeds which remain viable for extended periods as I bet you already know. I’m not sure of a long term storage solution.
Besides the mold, seeds that are too wet for too long will have embryo expulsion. Where the tiny part that would become the tree comes out. At first glance one might think they are sprouting, but under further examination it’s the embryo. Game Over!
