Nice videos. In the fall of 2015 I scored some paw paw seeds from the local university’s Ag department. I buried them in the woods behind my house and flagged the spot hoping to see some growth the following spring. I never saw anything last year so I assume my natural stratification did not work. If I get paw paw seeds again I’ll try your method.
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I just planted all of mine as seeds one inch deep in 12" pots and they all 30 of them came up in about two to three months. It was about this time last year when I started them. They grew to about two foot tall, some runts about eight inches. I planted some in 4" pvc pipes that I’ll just cut with a skill saw on each side to get them out. Others I found it was easy to just make round paper pots with house wrap. I just cut and rolled loosely around a 4"pipe then stapled the end seams. I’m planting the taller ones this year in a couple weeks. I still have some brush to clear out of the way and the ground is still frozen anyway.
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When i got first time my paw paw seeds i didn’t knew that they need stratification, i planted seed in spring and waited and waited and nothing was growing, after few months i lost patience and i digged out all seeds and cut them in half and all seed was rotten 
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Second time i have tried like i described in my videos and i got from 20 seeds 100% germination and now i use this way with paw paws few years and i have very high germination percentage.
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I thought that by planting the seeds directly in soil in late fall they would stratify over winter and pop up in spring.
Thanks for the videos misoo83. I will follow your method when I germinate my seeds. Maybe I missed it but what temperature range do you aim for during germination?
Yes, that is how nature does it so I’m sure it would work. I got my seeds around December and haven’t yet choses the precise locations for planting. Plus by pre-germinating them and planting in the Spring (fewer opportunities for critters) I hope to increase my chances.
Desirable temperature is between 15-30 °C.
I bought mine off of ebay from two different sellers. Both said they were already stratified. Five from one. and twenty-five from the other who said he collected them from his favorite tasting fruits from his adventure to several Pawpaw patches in different states. Hopefully I should have a good mixture of trees. I grew mine in my greenhouse which is shaded by trees for most of the middle portion of the day. You can plant them in the ground and let stratify over winter, but the chances of them surviving to grow into a tree are slim. It’s best to babysit them for a year or two and then plant out. I want to add that some of these came up with no leaves. I almost pitched them but was glad I didn’t. They grew leaves in about two weeks. So if yours come up and you think the leaves ripped off just wait.
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One year old seedling with roots 40 cm and plant above ground 10 cm 
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For comparison, here is one started indoors under lights in the winter using a root pruning container system. The picture was taken the following July:
It has about 2 more months of growth before our growing season ends in September to be a year old. The container is nominally 1 gal. The smaller ones behind it were started the same way but with a second batch of seeds in early spring so they have a few months less growth.
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What is your fertilizer?
You have a nice tree. The one thing I don’t like is that your air root pot has stopped the tap root from growing, or it’s curling up. it would be interesting to see what the root ball looks like. It should be about half of the height of the tree.
Just use osmocote plus when seedlings are that little.
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I think some of the accelerated growth is due to the container system not the fertilizer. Some trees like pawpaw have very long tap roots that ensure access to water when the tree is young and establishing. They put a lot of energy into that tap root. The amount of water and nutrients a tree can uptake can be a function of the number of tiny terminal root hairs in the root system.
The Express tray 18s, prune that tap root at slightly less than 4" which forces secondary and tertiary branching. Just before the 18s are full of roots it becomes much harder for water to infiltrate the container due to the roots filling it. At this point (usually 12-16 weeks) I transplant into the 1 gal Rootbuilder II containers. When these roots grow out, the root pruning process repeats. If I plan to maximize the growth of a fast growing tree in one season like a chestnut, I’ll do a second transplant into a 3 gal Rootbuilder II in late spring or early summer. In the case of pawpaws my objective was different. I was not trying to maximize growth, I was trying to control sun access for the first two seasons. So, I kept them in these 1 gal containers for 1 full season, overwintered them in a cold room, and then transplanted them to 3 gals for the second season. They are now starting their third season and I just finished planting them at the farm.
I think the energy the tree would normally spend growing a tap root is redirected to top growth and producing more root branching. More early root branching means more terminal root hairs which means it can collect water and energy more efficiently contributing to early growth.
When trees hit my native heavy clay soil (and they don’t get supplemental water once planted at the farm), the rate of growth slows, but I still have healthy trees compared to any bare root tree I’ve ever planted. If you can provide supplemental water after planting until the tree is fully established, I see no downside to growing trees in root pruning containers except the cost and effort. If you are planting trees in the field like me with no supplemental water for the first year or two, success will depend on your climate. I fortunately enjoy fairly dependable spring and fall/winter precipitation and periods of low water in the summer are fairly short. This lets me plant and forget trees at the farm. Folks with back yard orchards who provide supplemental care should have no issues with a system like this.
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Jack,
Did any of Jerry Lehman Pawpaw seeds that you got from Cliff England sprout? Brady sent to me a Kentucky Champion Pawpaw seedling a few years back and it grew real well. I am taking a Scion from it and will graft to my Shenandoah to speed up the fruiting time to see how big and good it is.
Tony
Dr Whitcomb did much of the early research on root pruning container systems. I’ve read most of his papers and in the early days his company, Rootmaker, was the only game in town. There are now a number of competitors producing root pruning containers with various levels of effectiveness. I ended up going with Rootmaker containers, but as long as the container systems conform to the principles of the underlying research any brand should do the same.
The rootmaker site has lots of comparisons of root systems at different stages: https://rootmaker.com/ . Over the years, I’ve occasionally removed the media from a tree just to look at the root system and mine look very much like those pictured on the site. I don’t make a practice of this because one of the advantages of the rootmaker containers is that you can extract and transplant trees with no disturbance of the root system.
As I said in my previous post, root pruning containers may not be a good choice for arid regions or in areas with prolonged droughts who can’t provide supplemental water.
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Tony,
Yes, I believe the one in the picture is 250x39 from Cliff. I’d say about half of the trees I just planted were 250x39 and the other half were KSU-VNS seeds. I’d say the 250x39 were more consistent but the larger KSU seeds produced seedlings about the same size as the 250x39. Keep in mind both may be somewhat restrained in size because I was more concerned with photosensitivity than maximizing growth as I mentioned in one of the above posts.
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I posted this pic on another thread but thought I’d include it here for completeness. I planted 23 of these trees this spring. It looks like 4 did not leaf out this spring so that is about an 80% success rate. Here is one of them now:
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Jack,
Hopefully some of those seedlings turned out to be the like of Halvin pawpaw then I will look you up for some scions one of these day.
Tony
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No problem!
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