Paw paw from seeds

[chickenlittle]

I have 3 trays of paw paw seeds started under lights with some success this time.

When I tried paw paw 2 winters ago, I ended up having all the seed get moldy when I tried to force germination after stratification and I tossed them.

I was all set to try again last winter but had enough other things started. These paw paw seeds sat in the fridge all year in a couple ziplock bags moist sphagnum moss. I got those out this Christmas and most floated. I only had a few apple seeds to grow so I figured I had nothing to lose with the paw paw seeds. I soaked overnight and planted in rootmaker 18s. I have not seen any topgrowth yet. Since I need a few more pots to plant the last of my apple seeds, I checked a few paw paws tonight. I was surprised to find each has a radicle root growing. So I have a decent chance of having quite a few paw paws to plant. These seeds came from some trees on Cornell University's campus and ripen in late Sept or early October.

 

[yoderjac]

I had pretty good success so far with pawpaw from seed. This thread was started by Todd but has the details of my experience in it: http://www.habitat-talk.com/index.php?threads/any-paw-paw-experts-transferred-from-old-forums.5710/

In general, they are VERY slow to start. I had the best success using heating pads under the 18s. KSU has some good info on growing them from seed. My primary seed source was from Cliff England with known parents but I also got some seed from KSU and others. I was primarily concerned with sun issues since they are photosensitive when young but produce the best in full sun. So, mine spent the first growing season in 1 gal RB2s on my lower deck. My lower deck only gets a small amount of direct sun in the morning followed by filtered light then shade in the afternoon. They grew very well in that environment. I tried moving a couple to a bit more sun the first year and they really got hurt. This convinced me I was on the right track.

I overwintered them in my cold room and transplanted them to 3 gal RB2s the following spring. I killed a bunch of them experimenting with biochar but I still have plenty. They spent the second season in the 3 gals and are now in my cold room. I plan to plant in the field them later this month or early next month. I'm sure I sacrificed some potential growth by keeping them in 1 gals for a whole season and 3 gals for a second season.

I'll takes some pictures after leaf-out this year. They root pruned well for me. The biggest thing I learned was that they need more patience than most trees I've grown.

Thanks,

Jack

 

[CAS_HNTR]

If you want to test your patience.....try and grow paw paws next to chestnuts! ;-)

 

[chickenlittle]

Based on past experience, a good portion of the chestnuts would be dead before the paw paw show top growth.

 

[chickenlittle]

About a month and a half, finally seeing top growth starting.

.

 

[yoderjac]

Congrats! KSU suggested that a soil temp of about 90 helps. I put heating pads under the trays. There was still an air gap between the bottom of the cells and the heating pad, but it was enough to raise the soil temp.

My biggest concern with pawpaw was the light sensitivity when young. I decided to keep mine in rootmakers for the first two growing seasons so I could control light exposure when young and I could still plant them in full sun to maximize fruit production. I don't have an easy way to plant them from containers larger than 3 gal RB2s so I kept them in 1 gals for the entire first season and 3 gals for the second.

It will be interesting to see how they do in the field after I plant them this spring.

Thanks,

Jack

 

[chickenlittle]

I will transplant these out directly from the 18s whenever they are ready. I have shaded spots that are on the moister side and can water once in a while if needed. I might transplant a few into larger pots but mostly have no interest in caring for them through the summer and winter in larger containers.

 

[yoderjac]

I will transplant these out directly from the 18s whenever they are ready. I have shaded spots that are on the moister side and can water once in a while if needed. I might transplant a few into larger pots but mostly have no interest in caring for them through the summer and winter in larger containers.

I've had little success planting directly from 18s. Some seedlings survive but few thrive. Pawpaws have a particularly long tap root. I'd be concerned that planting directly from 18s without a sufficient root ball may be problematic. They are an understory tree so I'm sure shady spots are good for them, but it is my understanding that they produce fruit the best in full sun. I know some folks plant them in full sun and put up artificial shade for the first two years and then take it down.

Thanks,

Jack

 

[chickenlittle]

Chestnuts did well for me out of 18s and I would think these will too if the root system is good enough. The area I will plant in is an open old orchard with lots of mature black walnut. I intend to eventually remove the walnut over time but for now it is acting as shade.

 

[yoderjac]

Chestnuts did well for me out of 18s and I would think these will too if the root system is good enough. The area I will plant in is an open old orchard with lots of mature black walnut. I intend to eventually remove the walnut over time but for now it is acting as shade.

I think pawpaw are tolerant of juglone so you should be ok. Perhaps you have better soil than I do that accounts for our different experiences planting chestnuts from 18s.

Thanks,

Jack

 

[yoderjac]

By the way, one thing I recall about planting the pawpaw seeds. I had some that were close to the surface of the 18s like some I see in your pictures. The stems lifted the seed out of the container and the leaves formed in the seed husk. Some had a hard time extracting themselves from the seed husks and were a bit deformed. I lost a few this way. Others that were planted deeper seed to pull the leaves out easier as the medium held on to the seed husk allowing the stem to pull the leaves out more easily. With the second batch, I learned that if they lift the seed husk out of the medium, it is best to keep it misted frequently. If the husk dries out, it becomes harder for the leaves to shed it.

Thanks,

Jack

 

[chickenlittle]

Thanks for the tip, Jack. I probably don't have room to plant everything if most of these 40 survive so a few losses will be OK. I also have 25 on order from the MDC. I might end up giving some of these away.

 

[yoderjac]

I'm headed to the farm tonight. I'm taking 6 of the smaller pawpaw trees with me to plant. I'm told that pawpaw don't transplant well and that there are often losses if planted in the fall verses the spring. I wonder if this specifically applies to bare root trees since the long tap root would be cut and the root system would be weak by comparison. It looks like we have a warming trend coming but I don't want to take too much risk. So, I'm going to plant a few trees each week when I go to the farm starting with smaller ones. I'll save the best trees for last to reduce the risk of loosing them. I'm not expecting losses, but since this is my first go around with pawpaws, I want to be cautious.

Thanks,

Jack

 

[chickenlittle]

Slow progress. The basement has been in the low 60s so I suppose they are taking their time. I turned the heat up a bit to see if they hurry up. I'm guessing I'll end up with 30 to 40 trees.

 

[yoderjac]

Outstanding! Great work.

 

[chickenlittle]

I did up the thermostat in the basement to a little over 70F and that seemed to help push growth. Right now I have 43 of 52 showing top growth. Pretty amazing given that most of the seed floated when I pulled them from stratification after 16 months. One appears to have rotted where it still stuck into the seed so I may lose that one. Some have managed to drop the seed ok while others are still stuck. We'll see if they figure it out.

 

[yoderjac]

Nice! Keeping the seed husk moist by misting can help it from drying out and becoming even harder to shed. I think the KSU research indicated the sweet spot was a soil temp of 90 degrees but you should verify that number. It has been a couple years since I looked. I placed regular heating pads below the 18s with a small air gap. That seemed to help accelerate growth. I think 70 is fine for air temperature.

I've also noticed that the float test seems much more accurate for nuts. It is pretty rare that a nut that floats will germinate for me. If I let them hydrate and eventually any begin to sink, they seem more likely. For most seeds I've dealt with, I've had a significant number of floaters germinate and grow well.

Thanks,

Jack

 

[chickenlittle]

Continuing to plug along. Looking more like I'll have about 30 good ones out of 52 seeds started.

 

[yoderjac]

Lookin' good.

 

[landlubber]

Very neat.