Stratifying Chestnuts in the Fridge

Jayber

5 year old buck +
I just put 2 bags of Dunstans packed in moist sphagnum peat in my fridge's vegetable drawer. For those that have done it:
1. What frequency do you use for checking them?
2. How do you check them, remove the seeds from the bags entirely?
3. Do you add water at any time and if so, how?
4. Any other tips you can provide?
 
I carefully look at them good through the bag every two weeks or so, any nuts that show any white mold I toss. I haven't had to ad any moisture to mine bags still show condensate.
Out of a couple hundred I've tossed six or seven, they have been in fridge since early October.
 
I carefully look at them good through the bag every two weeks or so, any nuts that show any white mold I toss. I haven't had to ad any moisture to mine bags still show condensate.
Out of a couple hundred I've tossed six or seven, they have been in fridge since early October.
How long are you planning to leave yours in the bags?
How long typically before they start to sprout?
 
60 days and you should see some tap roots

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I'm just starting to see a few with radicles peeking out, some take longer than others. I'll leave them in the bags for another three to four weeks then transfer them to trays and from there to roottrapper or power pots.
I'm still a neophyte on the stratification stuff myself.
 
I see a wide range in Chinese Chestnuts on when they germinate (produce a radicle) if they are only stratified 60 days. Jack Yoder and I tracked two different groups in 2015 and I can say 85 days at 34 degrees produced excellent germination rate.

In about two or two and a half weeks I will begin to put mine in growing media and place them in a grow box under lights.

Regarding your checking the chestnuts, set your phone for the 1st day of the month and the 15th day of the month with an alarm. No matter what you do, a small few will not make it to a viable seedling. That may be 1 out of 20 or 1 out of 12. We can afford those percentages - we don't want to lose 1/3 of them. That would mean we made some bad mistakes somewhere.

Condensation in the bag is good as long as we don't see any white moldy chestnuts. Good luck to you. Chestnuts are vigorous growers which makes in fun to watch them go.

Wayne
 
I'm convinced that most mold issues come from exposure at collection, but you can make the problem worse by creating good conditions for mold growth. I find bleach solutions do as much harm as good. Chestnuts are high in carbs and very attractive to mold. It is a balancing act trying to create good conditions for cold stratification and germination without encouraging mold.

The first step I take is to wash them individually under water.

Cold stratification requires both cold and moisture. For chestnuts it is 60 to 90 days. With sufficient moisture they can germinate closer to the 60 day mark. As moisture levels drop, cold stratification slows. If moisture levels drop low enough, cold stratification stops and they just go into sort of a suspended animation. Of course, moisture is one of the conditions that encourages mold. So, it is a balance.

The next step I take is to hydrate the nuts. I separate them into groups as I wash them. Mold moves quickly from nut to nut, so if you do everything in one batch, you have more chance of losing everything. I put each batch in a clean pot with water to soak over night and fully hydrate.

I like to use long-fiber sphagnum because it has some natural antifungal properties. The best is live sphagnum but that is hard to find most places. Home depot caries dried long-fiber sphagnum and it second best. I soak it in water so it absorbs all it can. I then put each group of nuts in a ziplock bag. I take a handful of sphagnum and squeeze it as hard as I can squeezing all the water out of it I can. This is about the right level of moisture. I put one fist full in with each bag. I label the bag, zip it half way closed, fold it in half, and put the bags in the crisper.

From here, there are a couple methods. For the first 60 days, you can ignore them as far as germination goes. The only thing you are checking for is mold. If you see signs of mold, try to keep the mold nuts away from all other nuts. Either discard moldy nuts or wash them again and put them in their own bag. Wash all the other nuts without mold in the bag again under running water. There should me no need to rehydrate. Discard the bag and sphagnum that was in the bag. Put the nuts in a new bag with new sphagnum. With any luck you won't have mold issues. It will largely depend on the source for your nuts.

After 60 days, a new factor comes into play. When a chestnut germinates, the radicle emerges from the pointed end and uses gravity to determine which way is up. This determination actually occurs a short time before the radicle is produced. The top growth will come from the same point and use light to determine which way is up. So, when you plant a nut, you want to plant it with the same orientation it had at germination. If a root radicle starts growing thinking one direction is down and you change the orientation, it will change the direction of growth, but it takes time and you can get a kink in the root that can be a problem in the future. A soft bend is not a problem but a sharp kink will be.

There are several strategies to deal with this. One is to simply plant the nuts after they have had at least 60 days of cold stratification but before root radicles begin. Plant them with the point to one side. If you are planting in an 18 indoors, put the chestnut in the corner with the point in the middle of the 18. Some folks put their nuts on top of the medium in an 18. I prefer to press mine down and cover them with media. This seems to reduce mold issues for me. The downside with this method is lower germination rates, and you are taking up nuts that will never germinate. One year Wayne and I compared our methods. I think there is a thread on here. He cold stratified for 80 days and got over 90% germination. I had plenty of nuts and 18s and was more concerned with timing than germination rates.

Another strategy is to orient the nuts so they are sitting on their flat side and let them germinate in cold storage. With this method, you check the nuts every few days after 60 days and plant them as soon as you see root radicles. It can be a pain with ziplock bags, so some use other kinds of plastic containers for this. After 90 days, just plant any nuts left.

I'm happy to answer any other questions you have as you go. I brought over some good threads from the old forum that are good background reading.

Thanks,

Jack
 
I see a wide range in Chinese Chestnuts on when they germinate (produce a radicle) if they are only stratified 60 days. Jack Yoder and I tracked two different groups in 2015 and I can say 85 days at 34 degrees produced excellent germination rate.

In about two or two and a half weeks I will begin to put mine in growing media and place them in a grow box under lights.

Regarding your checking the chestnuts, set your phone for the 1st day of the month and the 15th day of the month with an alarm. No matter what you do, a small few will not make it to a viable seedling. That may be 1 out of 20 or 1 out of 12. We can afford those percentages - we don't want to lose 1/3 of them. That would mean we made some bad mistakes somewhere.

Condensation in the bag is good as long as we don't see any white moldy chestnuts. Good luck to you. Chestnuts are vigorous growers which makes in fun to watch them go.

Wayne

Wayne,

We must have been typing at the same time. Glad to see you posting here. You're a great resource for the chestnut guys. I'm done with Dunstan chestnuts for now. This year I'm growing some ACs and a few Chinese chestnuts that came from the AU Buck III and IV trees I got from the Wildlife Group. The IV's are supposed to drop a bit later so I hope some of the offspring of the cross between the two retain that characteristic. Most of my seedlings this year are apple. I'm just starting to do them in volume. The other tree in the chestnut family I'm hoping to work with is Seguin. I bought a boatload of seed from Schumacher but they were delivered out of season and had mold exposure. None of them germinated. I just ordered a few Seguin trees from the Wildlife Group. I plan to grow them 3 gal RB2s and use them as a source for nuts for propagation.

What does your plan look like for this year?

Thanks,

Jack
 
Thanks for all the great input!

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Thanks for all the great input!

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Jaber,

Are you starting them indoors under lights or do you plant to direct seed them?

Thanks,

Jack
 
Jack

I have Chinese Chestnuts, sawtooth oak, swamp white oak, DCO, bur, and chinkapin. I will graft some pears and persimmons. Got my greenhouse built and will learn how to grow in it. Will start a ton of stuck in my growing boxes.

Going to try to collect rain water off my garage to use in the greenhouse. I had a good Sept and October - shipped 150 orders of Chinese Chestnut (8,817) to 33 states. Was able to increase the number of trees I collected from. It has been great fun helping first timers learn how to grow chestnuts whether in containers or by direct seed.
 
Jack

I have Chinese Chestnuts, sawtooth oak, swamp white oak, DCO, bur, and chinkapin. I will graft some pears and persimmons. Got my greenhouse built and will learn how to grow in it. Will start a ton of stuck in my growing boxes.

Going to try to collect rain water off my garage to use in the greenhouse. I had a good Sept and October - shipped 150 orders of Chinese Chestnut (8,817) to 33 states. Was able to increase the number of trees I collected from. It has been great fun helping first timers learn how to grow chestnuts whether in containers or by direct seed.

Sounds like you're enjoying your retirement!
 
Jaber,

Are you starting them indoors under lights or do you plant to direct seed them?

Thanks,

Jack

I haven't got that far yet, to be honest. I was hoping to go direct, but I'll have to see how they progress. If I have to I'll do pots and purchase some growing lights.
 
I haven't got that far yet, to be honest. I was hoping to go direct, but I'll have to see how they progress. If I have to I'll do pots and purchase some growing lights.

If I were direct seeding, I would probably let nature do the cold stratification but simply planting them in the fall. If it is too late to plant in your area and you want to direct seed, I would probably skip putting medium in the ziplock bag. I'd hydrate them well and store them in the bag without added moisture. This should slow cold stratification so they don't produce root radicles until spring when you are ready to plant them.

The problem with growing trees in containers is a circling or j-hooking tap root. The seedling will put a lot of energy into a deep tap root. When it hits the bottom of a normal container, it will circle and follow the container or j-hook. While the tree will look fine when it young, eventually the roots will constrict. If you use a root pruning container system like Rootmaker, you will need at least 2 or 3 containers for each tree. The first stage is Express tray 18s. These are good for 12-16 weeks. They prune the tap root causing early root branching. The problem is that if you plant out of 18s, the root system is so small and shallow, trees don't flourish and won't even live in many cases without supplemental care. They do much better when transplanted into 1 gal Rootbuilder II containers and are allowed to fill them before planting them in the field in the fall. They do even better when transplanted a second time and are allowed to fill 3 gal RB2s but your growing season may not be long enough for that.

As for lights, inexpensive cool fluorescent shop lights rigged on chains or string so they can be constantly adjusted to be kept a couple inches above the trees are the best bang for the buck.

Best of luck,

Jack
 
Thanks again for all the insight everyone! Sounds like it can get pretty scientific on the various approaches one can take. :)

Way too late where I'm at to try the el natural means of cold stratification. Will have to proceed with the alternative route.

If one were to put the seeds in a bag without any medium, is the notion to add peat when things get closer to Spring or leave them that way and they'll eventually sprout?

I may try a combination of things: bags with peat, flat containers with peat and bags without. I originally didn't soak the seeds, which sounded like a great idea, so I pulled them out this morning (only 1 day in) and now have them in H2O.
 
Jayber,

I would not put peat moss in the bag. It can hold too much moisture and we see soft chestnuts or mold. I am attaching a photo of what I add to the sandwich bag. I hope this helps.
Sphagnum Moss Bag.JPG

I generally buy that Lowes.
 
I put mine in gallon ziploc bags mixed with peat (the brown powder) only very slightly moistened. Bags are poked with holes with a needle. turn every couple weeks until the end of the year at which time I add quite a bit of moisture with a spray mister. Enough to begin the stratification process, but not enough to drip when a handful is squeezed. Again turn bags over every couple weeks. When they start sprouting in late February stop rotating the bag to minimize the radicle changing directions, and start direct seeding them. This is my fifth year of doing this (although the first year I moistened them immediately upon storage and they started sprouting in December) successfully. Got my first couple burrs produced last fall. One of my favorite attributes of the chestnut is they are still holding leaves.
 
Thanks again for all the insight everyone! Sounds like it can get pretty scientific on the various approaches one can take. :)

Way too late where I'm at to try the el natural means of cold stratification. Will have to proceed with the alternative route.

If one were to put the seeds in a bag without any medium, is the notion to add peat when things get closer to Spring or leave them that way and they'll eventually sprout?

I may try a combination of things: bags with peat, flat containers with peat and bags without. I originally didn't soak the seeds, which sounded like a great idea, so I pulled them out this morning (only 1 day in) and now have them in H2O.

IndianSam starts them without added moisture and then adds the damp medium later to time the germination. If they don't have added moisture he has kept them in the fridge for over a year and planted them the next year with good germination rates. However , if you plan to direct seed them, I would not bother adding moisture. Just direct seed them 60 to 90 days before your last threat of frost and let nature cold stratify them in the spring.

Thanks,

Jack
 
By the way, as far as medium goes, the only different between sphagnum peat moss and long-fiber sphagnum is where in the bog they harvest it from. The fine peat has been dead and decomposing so long that it has lost any antifungal properties. Folks have told me that on occasion, the dried long fiber peat will sometimes start actively growing again if the conditions are right. It is important to get the moisture right, but there are a number of ways to do that. I'm really not sure how much the antifungal properties of long-fiber help, but mold can be such an issue if nuts are exposed at the collection source that every little bit of protection helps.

Thanks,

Jack
 
Here is what I was going to use.

f78f0b6654d4a31b86de172e2254cb42.jpg
 
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