Random thoughs on Stratifying Chestnuts

[yoderjac]

I just started my nuts tonight. I'm learning more and more each year and finding new factors to consider. In the past, I and many others have had mold issues with chestnuts. This year I had none. Here are a few things I did differently and why I think they had a positive impact.

• I gathered the nuts myself directly from the burs on the tree before they hit the ground. I was able to do this because the particular chestnut variety I'm growing this year are Dwarf Asian Chestnuts (also called Seguins Castanea Seguinii) and I'm growing them in Rootbuilder II containers on my deck. Thus, I could check them daily and remove the nuts as soon as the opened.
• Patience! I lack this. In many years, I was in a hurry to start my trees under light. My thinking was the sooner they start, the more growth in the first growing season. In some years, I even planted them in the spring from 1 gal RB2s. I've found that my trees in the field do the best if I do multiple transplants and field plant them after a full growing season from 3 gal RB2s. (Detail here: http://habitat-talk.com/index.php?t...h-rootmakers-transfered-from-qdma-forum.5556/). I've learned that my growing season is plenty long and starting chestnuts in December doesn't add much if anything. WBPdeer (Wayne) and I did an experiment one year showing how much better germination rates are with 90 days cold stratification than 60 days. This year all of my chestnuts got 90 days cold stratification.
• Moisture distribution. In previous years, I recommended using long-fiber sphagnum because it has more antifungal properties than the fine peat. In the past, I always thought the primary factor was total moisture in the container. I would take a fist full of long-fiber sphagnum, squeeze out the water and put it in the bag with the chestnuts. I'm now beginning to believe that the distribution of the moisture is just as or more important than overall moisture content. I use regular fine sphagnum this year. I got it damp and filled the ziplock bag about 1/2 way full. I then "planted" the nuts in the medium pushing them down 1/2 way to the bottom of the peat. I then closed the ziplock 3/4 way and folded over the top of the bag storing it in the crisper on it's bottom with the ziplock up rather than on its side. When I planted the nuts tonight, all were showing at least the beginning of a root radicle. There were no dark areas on them as in the past. I think those dark areas were places that had significant contact with water. Having the nuts inside the medium meant the moisture was well distributed around the nut with no contact with plastic where condensation could pool. I also made sure none of the nuts touched each other. This is much less space efficient but much more effective for me.

We will see how things progress over time, but I'm off to a very good start this year.

Thanks,

Jack

 

[silver_yummies]

Good stuff. When did you start the cold stratification process this year? I started Nov 11 and didn’t plan on planting mine until Feb sometime.

 

[Merle Hawggard]

Good luck with them Jack!
This is the first year in quite a few that I don't have any in the fridge. We had a few burs on the dunstan trees last year so I may have some next year to plant.


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[yoderjac]

Good stuff. When did you start the cold stratification process this year? I started Nov 11 and didn’t plan on planting mine until Feb sometime.

Mine varied this year. Since I was collecting my own nuts from trees growing on my deck, as soon as a burr opened enough for me to get the nut, I would and I'd immediately put it in cold stratification. Some bags only had a nut or two and others had more. My start times are a bit unusual too. The Seguins were purchased dormant last winter and planted in 3 gal RB2s and put in my cold room. I brought them in, woke them up early, and put them under lights. I they had burrs starting even before I took them outdoors. So, some of them actually produced nuts in late August. I think the last nuts were in the second half of October.

All of my Allegheny Chinquapin nuts were collected on 9/16 this year from native trees on my farm. They don't need cold stratification but were put in cold storage to delay germination. Most of them had root radicles when I planted them on Monday.

Thanks,

Jack

 

[yoderjac]

Good luck with them Jack!
This is the first year in quite a few that I don't have any in the fridge. We had a few burs on the dunstan trees last year so I may have some next year to plant.


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So far, I've gotten 1 nut from 1 Dunstan tree. I'm hoping like you to see some improvement in the next few years.

I know you've done some nut grafting in the past. I have a bunch of ACs this year. I decided to start 7 of them in the dark. I plan to try etiolated grafting using scions from Seguins (Castanea seguinii ). I have no idea if it will work.

Thanks,

Jakc

 

[silver_yummies]

So this is my first year growing these from seed. I’m curious if I need to buy a heating pad of some sort to place under the seed trays? The grow lights are setup in the basement where it’s fairly cool - 55-60 degrees is guess. I will open the furnace vent in that room to try and warm the room up but was wondering how crucial warmth is to wake them up or if the lights are enough.

Another question - what do you usually run your lights as far as time off and time on? 15 hrs on and 9 off or do they need more light than that??

 

[yoderjac]

I prefer inexpensive shop lights because they are cool and can be rigged so they are only a few inches above the trees. Light intensity decreases with the distance squared. Most grow-lights are hot. They put out a lot of light but much of the energy goes into heat. Because of the heat, they need to be kept far enough away from the trees so they don't have ill effects from the hotspot. I hang fluorescent shop lights with cords and prussic knots so I can easily adjust the height. I use the Express tray 18s rather than the regular 18s. This allows me to arrange trees by height and hang the shop lights at an angle to keep them a few inches above all the trees.

As for ambient temperature, 70 degrees is great and 80 even better. That is not to say trees won't grow at 60-65 but growth will be slower. I don't use heating pads for chestnuts (I do for pawpaws). I open the vents in my basement and close the upstairs vents and keep the basement door open. I've got ceiling fans upstairs to draw the heat up. This helps keep my basement about the same ambient temperature as my house, around 70. I then put small oil filled electric heaters in each of my grow enclosures so the ambient temperature around the trees is a few degrees higher.

I run 15 hour days for all my trees. No artificial light will be as effective as growing season sun. Even keeping my shop lights close to plants, I tend to get some lanky trees. I use safety flags from TSC as stakes. They are very thin and flex easily which young trees need. They keep them growing straight. After they are outside for a bit, they harden up and don't need the stakes.

Others grow them other ways, but this is what has worked the best for me over the years.

Thanks,

Jack

 

[andrew bullard]

I have 2 pounds of Dunstan chestnuts in the refrigerator where they have been since November. They're in a one gallon ziplock with a damp paper-towel. I'm planning to leave them like this until mid March then add a few handfuls of damp peat moss to the bag. My intent is to direct seed the nuts that produce a radical in mid to late April. I'm hoping my timeline will work out.

 

[silver_yummies]

Thanks Jack! I just went through my ziplock bags tonight and threw 4 moldy ones away but still have 94 left. I also bought individual 18s so I can rearrange them as they grow. I have 3 of the led shoplights that I will use and come up with something to get heat in that room. I also have chain links so I can easily adjust height as they grow. A couple had the radicals exposed when I checked them but wanting to wait until the end of the month at least to start them. I bagged them on 10/20/17.

 

[yoderjac]

I have 2 pounds of Dunstan chestnuts in the refrigerator where they have been since November. They're in a one gallon ziplock with a damp paper-towel. I'm planning to leave them like this until mid March then add a few handfuls of damp peat moss to the bag. My intent is to direct seed the nuts that produce a radical in mid to late April. I'm hoping my timeline will work out.

IndianSam on the QDMA forum (not sure if he is here under another name) used a similar technique. I've done a lot of looking into cold stratification of chestnuts. As moisture content in the nuts drops, cold stratification slows. When it gets low enough, cold stratification stops completely and the nuts go into sort of a state of suspension. IndianSam would store his nuts in ziplock bags in the crisper with no added moisture. He said he was able to keep nuts for a year like that an then add moisture to start cold stratification and still get them to germinate. It will all come down to the moisture content of your nuts. 60 days is the minimum. Wayne (wbpDeer) and I did a comparison one year. I pulled all of my nuts out of cold stratification after 60 days and he after 90. He got much better germination rates than I did. I was in the low 70% range and he was well over 90%.

Based on that, if I were trying to get a radicle in mid-April, I would hydrate them well but then store them with no added moisture in ziplock bags in the crisper. Then in mid-Jan, I would pull them out and distributed them through more ziplock bags with plenty of damp sphagnum and put them back in the crisper until mid-April.

Thanks,

Jack

 

[andrew bullard]

IndianSam on the QDMA forum (not sure if he is here under another name) used a similar technique. I've done a lot of looking into cold stratification of chestnuts. As moisture content in the nuts drops, cold stratification slows. When it gets low enough, cold stratification stops completely and the nuts go into sort of a state of suspension. IndianSam would store his nuts in ziplock bags in the crisper with no added moisture. He said he was able to keep nuts for a year like that an then add moisture to start cold stratification and still get them to germinate. It will all come down to the moisture content of your nuts. 60 days is the minimum. Wayne (wbpDeer) and I did a comparison one year. I pulled all of my nuts out of cold stratification after 60 days and he after 90. He got much better germination rates than I did. I was in the low 70% range and he was well over 90%.

Based on that, if I were trying to get a radicle in mid-April, I would hydrate them well but then store them with no added moisture in ziplock bags in the crisper. Then in mid-Jan, I would pull them out and distributed them through more ziplock bags with plenty of damp sphagnum and put them back in the crisper until mid-April.

Thanks,

Jack

Jack,

Thanks for the advice. I didn't want to add damp sphagnum too early in fear of radicals starting before I was ready to plant. I won't be back on the east coast until mid or possibly late April. The chestnuts are in my dads care and I don't want him to have to plant and care for 40+ chestnuts.

I'd like to plant (direct seed and tube) them with a good radical but isn't it possible for them to be too far along? If not, I'll have him add sphagnum in a few weeks. Could you define "hydrate" for me. They have had a damp paper towel in the bag for a few months to keep them from drying out but have not been soaked. Thanks!

 

[yoderjac]

Jack,

Thanks for the advice. I didn't want to add damp sphagnum too early in fear of radicals starting before I was ready to plant. I won't be back on the east coast until mid or possibly late April. The chestnuts are in my dads care and I don't want him to have to plant and care for 40+ chestnuts.

I'd like to plant (direct seed and tube) them with a good radical but isn't it possible for them to be too far along? If not, I'll have him add sphagnum in a few weeks. Could you define "hydrate" for me. They have had a damp paper towel in the bag for a few months to keep them from drying out but have not been soaked. Thanks!

Sure, by hydrate, I don't mean adding additional moisture to the bag like a damp paper towel or medium. When you get nuts, depending on how they were collected, stored, or shipped, they can lose moisture content inside the nut. If I don't collect the nuts myself fresh from the tree, I typically wash them off individually under running water. Mold can move from nut to nut quickly but not be visible yet. I try to wash off anything I can. I don't use bleach a bleach solution like some folks. I found that bleach reacts with the shell can actually make mold issues worse. Once year I had a mold issue and tried washing individual nuts in a 10% bleach solution. The reaction between the nut shell and the bleach burned the hair off my knuckles. I think bleach can compromise the shell making it easier for mold to penetrate the nut.

Back to hydration. So, after I wash the nuts (I don't bother if I pick the nuts from the tree myself and know they are fresh), I put them in a bowl and fill it with water. I let them sit in it over night. This gives the nuts a chance to fully hydrate. I then remove them from the water pad the excess water from the outside and put them in for cold stratification. The nuts are fully hydrated but have no added moisture at that point.

It is the added moisture from the damp sphagnum in the bag that they need for cold stratification. If you are trying to put them in suspended animation, I would fully hydrate them but not add any source of water inside the bag. Then when you are ready add the damp sphagnum.

As I recall, BigEight on this forum does something like this and then adds damp sphagnum later to try to time the production of root radicles. He may have some better hands-on insights. I always start mine indoors under lights.

One more thing to consider for future years. I'm presuming the reason you want to time them to produce a radicle in April is because you plan to direct seed them. If I were going to direct seed chestnuts, I think I would plant them in the fall and let nature do the cold stratification. I would think you would get pretty good germination rates if you can control planting depth and provide proper protection. I think some guys who direct seed actually put a couple nuts in the ground for each tree. If more than one nut germinates, the cull all but one. They only need protection from squirrels and such that first winter. Once they germinate you can tube them. Just an alternative to consider.

Thanks,

Jack

 

[andrew bullard]

Jack,

Thanks again. I live a very long way from my property (4500 miles) and can't always be there when I'd like. I was on the property in late December and probably could have direct seeded then but for some reason I have it in my mind that the nuts should be artificially cold stratified and have a radical prior to planting. I may try to direct seed without a radical next year if I can time it correctly.

These chestnuts were ordered from chestnut ridge of pike county and immediately refrigerated. They have not been rehydrated. If I plant them without a radical in April could they still possibly grow? I have enough to experiment here. I may ask my father to stagger the sphagnum and see what works best.

 

[yoderjac]

Everyone has their own constraints they need to work within. I've been very happy with the condition of chestnuts I've received from Chestnut Ridge. I've had very little mold issues with them compared to nuts I've received from other sources. Hydration is a good practice, but if the nuts did not lose moisture prior to you receiving them it is not a must.

I've used several approaches over the years. In some years, I wanted to time my trees to be ready to move outside when our last chance of frost passes in mid-April. In order to do that, I only had time for 60 days of stratification rather than the full 90. 60 is the minimum. Some nuts will stratify faster than others due to water content and the unique characteristics of an individual nut. None of the nuts had root radicles showing when I planted them and I got about 70% germination. So, having a root radicle showing at planting time is not a must. It is just an indicator that the nut is fully stratified and starting to germinate. Whether they will grow or not will depend if they are stratified enough.

One more thought to consider: Once a nut is stratified, a few days before a root radicle emerges, it decides which way is up and which ways is down. If you just jumble your nuts in a bag, root radicles could grow in any direction. Stems emerge from the same place in the nut and grow up. If you change the orientation of the nut after it determines up and down, it will take some time for the nut to reorient itself. In the mean time the radicle keeps growing. You can end up with a looping tap root which can be a problem later in the life of the tree because it can constrict itself.

If you use a deep container of media (say fill the ziplock 3/4 with damp sphagnum) and then carefully place the nuts with the flat side down and cover them with more damp sphagnum, the radicles will grow the proper direction for planting. If you keep them in the crisper, root radicles will grow reasonably slowly when they emerge. As long as they don't hit the bottom of the container and turn, you can plant them fine. You do need to be careful when dealing with nuts with longer root radicles that you don't break them.

Thanks,

Jack

 

[andrew bullard]

Excellent information, thank you.

 

[yoderjac]

Just got back in town and watered my 18s. No sign of top growth yet from anything but it has only been a week.

 

[yoderjac]

This is day 9, not signs of top growth yet.

 

[H20fwler]

I've got a bunch of mine starting to show radicles now, they are Dunstan's from my trees and from Chestnut Ridge. I'm hopefully going to leave them in the fridge until late March early April and direct seed into my shrub strips this year.

 

[yoderjac]

I've got a bunch of mine starting to show radicles now, they are Dunstan's from my trees and from Chestnut Ridge. I'm hopefully going to leave them in the fridge until late March early April and direct seed into my shrub strips this year.

Best of luck with those. Post some pics when you get them in the field!

 

[H20fwler]

Best of luck with those. Post some pics when you get them in the field!

Will do. Had pretty good luck with it last year, here is one of them;