Help! Insane amount of mold on all of my trees in coldframe :'(

[TheEmpireNeverEnded]

Good video Sorce. I pretreated my area under my sunroom for these varmints as well as insects
and will be moving my trees in over the next 3 weeks hopefully, as well as following up
with a dormant oil spray.
@TheEmpireNeverEnded I lost 75% of my collection in my 1st and last cold frame
roughly 15 years ago. Not due to mold and damp conditions, rather transpiration, and heat.
Can't blame the cold frame, just the improper use of the cold frame.
Still, had I not used the cold frame, I would have some very nice conifers now, that I don't have.

I seem to have missed what kind of trees, roots and foliage you're protecting with this contraption.

Could you elaborate of the transpiration and heat death of your trees? I would like to know more so as to know what to avoid.

 

[TheEmpireNeverEnded]

Seems collecting them all in one place is the Best Invite for V.C. (critters.)

The ONLY VC terrors I ever read of were when bunched, or "wintered".

It's because we create a smorgasbord for the little fuckers. They are creating an "eat and bang" around our trees...an environment they Don't get otherwise. All the trees get eaten, not because one mouse found it's food, but because by the end of the season there are 40+ hungry inbred VC in the shelter.

This environment isn't possible with ONe tree alone on the ground.

So if the tree doesn't need protection....don't protect it!

100% is only possible 2 ways.

1. Very Healthy Local Material Unsheltered.

2. Anything else in a Professionally Climate Controlled Greenhouse..... with Cats...cats that don't knock small trees over...yeah...skip the cats!

Sorce

That bonsai mirai video was excellent, thank you.

 

[coh]

The rest of the photos...

One big no-no in my opinion is putting the deciduous trees in there with leaves still on them. You should have removed those leaves. If they don't come off willingly, cut them off. Otherwise you have a breeding ground for all kinds of fungus. Get the dead ones off the mulch and out of the pots too. That's a big step in winter hygiene.

 

[TheEmpireNeverEnded]

One big no-no in my opinion is putting the deciduous trees in there with leaves still on them. You should have removed those leaves. If they don't come off willingly, cut them off. Otherwise you have a breeding ground for all kinds of fungus. Get the dead ones off the mulch and out of the pots too. That's a big step in winter hygiene.

Thank you I had a sense that this was part of the problem. I'll do this right away.

 

[Japonicus]

Could you elaborate of the transpiration and heat death of your trees? I would like to know more so as to know what to avoid.

1st I love your cold frame! Nice work, clean lines.
A quick framed 1/4" metal screen lid sounds perfect. Good idea.
Inquire about using diluted lime sulphur on your JM's. Not sure if it would help the mold or not.

I used to dig the ground up and spade/till it well, for each tree prior to healing them into the ground.
Lots of work, but if your collection never increases in quantity, the ground is easier to break up each year.
Still, caught in many Arctic blasts and doing this for an entire collection, and procrastinating,
I was tiring of getting caught with my pants down and my fingers ready to crack like ice cycles.
To combat this I built a cold frame entirely above ground, and just a treated 2x4 frame covered
with heavy mil opaque plastic. Out of ignorance, unlike Ryans suggestion to rest them on the ground
I built a 2 step bonsai bench with the frames sides just tall enough to accommodate my needs.
I thinking...Winter dormancy reduced the need for water more than it actually does, and unlike you,
did not have a thermometer inside where I could see the min/max temps. The Winter was harsh
the ground frozen longer than usual, not watering enough, and opening the sides more,
just allowed for too much water loss and too little air movement, too high a temperatures,
that I just nuked them. They transpired without a constant replenishment source.

Now, on the perimeter inside, on the ground, off the bench, where water could flow through
across the floor when it rained and snow melted, the bonsai that was there, they all survived.
Unfortunately, this was only my youngest smallest bonsai. One I still have today, a procumbens
which I call Alpha I've had since before then sometime. Not much girth to this day, but that's what
happens when you start a procumbens without growing it out otherwise.

 

[Japonicus]

Is this freeze damage?

 

[TheEmpireNeverEnded]

1st I love your cold frame! Nice work, clean lines.
A quick framed 1/4" metal screen lid sounds perfect. Good idea.
Inquire about using diluted lime sulphur on your JM's. Not sure if it would help the mold or not.

I used to dig the ground up and spade/till it well, for each tree prior to healing them into the ground.
Lots of work, but if your collection never increases in quantity, the ground is easier to break up each year.
Still, caught in many Arctic blasts and doing this for an entire collection, and procrastinating,
I was tiring of getting caught with my pants down and my fingers ready to crack like ice cycles.
To combat this I built a cold frame entirely above ground, and just a treated 2x4 frame covered
with heavy mil opaque plastic. Out of ignorance, unlike Ryans suggestion to rest them on the ground
I built a 2 step bonsai bench with the frames sides just tall enough to accommodate my needs.
I thinking...Winter dormancy reduced the need for water more than it actually does, and unlike you,
did not have a thermometer inside where I could see the min/max temps. The Winter was harsh
the ground frozen longer than usual, not watering enough, and opening the sides more,
just allowed for too much water loss and too little air movement, too high a temperatures,
that I just nuked them. They transpired without a constant replenishment source.

Now, on the perimeter inside, on the ground, off the bench, where water could flow through
across the floor when it rained and snow melted, the bonsai that was there, they all survived.
Unfortunately, this was only my youngest smallest bonsai. One I still have today, a procumbens
which I call Alpha I've had since before then sometime. Not much girth to this day, but that's what
happens when you start a procumbens without growing it out otherwise.

Thank you for saying so. I had a helluva time getting it into the ground, because it weighs several hundred pounds. I do need to find some chemical application to treat the trees with. I only just got into this in late summer, and haven't faced fungus yet, and thus don't have anything on hand. How would you water when it was below freezing outside? Or would you just pack snow on top?

 

[TheEmpireNeverEnded]

Is this freeze damage?
View attachment 222028

It very well may be. That or dieback from my mishandling earlier this year. That may have been one of the branches mold was growing on. The blackish gobs are leaf-remants. I have no idea why the branch itself is so dark. It could have gotten too cold the week before I put the trees in the box. I really abused this poor little kotohime.

 

[Tieball]

Only speaking about American Elm...and what I do that may add thoughts for you. I think my winters may be like yours or perhaps even colder. More harsh winds. I’ve never parked an American Elm in any artificial care. My American Elms stay outside all year. I have not lost any of the trees. The only added care I may do is if a tree, usually a seedling level from a cutting, is in a smaller plastic pot...then I simply dig a hole for that pot and plant it all up to the lip of the pot...just in the ground...earth insulation during the winter.

I don’t mulch...in my experience - a breeding ground for mold and mildew any time of the year. I did try white pine needles one winter (thought it would be a clever idea since I have so many needles off trees)...never again....worse than mulch.

Around me the trees are in the ground...one of the key ingredients is air movement...and plenty of sun exposure. Nature does well...far better than me. I want freezing temperatures....the trees know what to do...so I let them do their thing. I try to not interfere.

Other trees. I may treat these trees different than the American Elms:
- Korean Hackberry trees, only 2 of them, in grow boxes, outdoors no special care, except I move the trees from a bench to the ground.
- Zelkova and Field Maple. For these I set up a simple windshield fence, top open....hoping winter buries them in snow.
- Hackberry, Celtis Sinensis, outdoors in the ground. Boxed Celtis just get a windshield around them during winter. Top open to whatever winter provides.
- Hornbeam, just in the ground. No special treatment. Outdoors all year.

 

[TheEmpireNeverEnded]

Only speaking about American Elm...and what I do that may add thoughts for you. I think my winters may be like yours or perhaps even colder. More harsh winds. I’ve never parked an American Elm in any artificial care. My American Elms stay outside all year. I have not lost any of the trees. The only added care I may do is if a tree, usually a seedling level from a cutting, is in a smaller plastic pot...then I simply dig a hole for that pot and plant it all up to the lip of the pot...just in the ground...earth insulation during the winter.

I don’t mulch...in my experience - a breeding ground for mold and mildew any time of the year. I did try white pine needles one winter (thought it would be a clever idea since I have so many needles off trees)...never again....worse than mulch.

Around me the trees are in the ground...one of the key ingredients is air movement...and plenty of sun exposure. Nature does well...far better than me. I want freezing temperatures....the trees know what to do...so I let them do their thing. I try to not interfere.

Other trees. I may treat these trees different than the American Elms:
- Korean Hackberry trees, only 2 of them, in grow boxes, outdoors no special care, except I move the trees from a bench to the ground.
- Zelkova and Field Maple. For these I set up a simple windshield fence, top open....hoping winter buries them in snow.
- Hackberry, Celtis Sinensis, outdoors in the ground. Boxed Celtis just get a windshield around them during winter. Top open to whatever winter provides.
- Hornbeam, just in the ground. No special treatment. Outdoors all year.

I find all of this information to be very reassuring. I will have to keep the moldy larger american elm out of the box for the rest of the winter. Where specifically do you put your american elms? Alongside a foundation or structure? On the south side of a building? The north side?

 

[Japonicus]

Thank you for saying so. I had a helluva time getting it into the ground, because it weighs several hundred pounds. I do need to find some chemical application to treat the trees with. I only just got into this in late summer, and haven't faced fungus yet, and thus don't have anything on hand. How would you water when it was below freezing outside? Or would you just pack snow on top?

Snow is awesome. As it protects from winds as well as transpiration if deep enough
it keeps the root zone happy as it melts. Not a steady unwavering supply in our area
that remains all Winter, so you must still check the roots and water when needed.
You do not water below freezing, rather as with any season of the year, when necessary.
You'll have warm spells, most rainy I think, but not always.

I watered at least once/month last Winter on average, skipping no more than 6 weeks at the peak,
but if you see where I'm keeping mine, they are in a very dry location where no rain ever reaches.
https://www.bonsainut.com/threads/winter-storage-and-reusing-last-years-mulch.36569/
I'm just getting trees from around the South to the North side of the house for Winter.
Then in the next week , 10 days I'll start huddling them together under my sunroom then mulch them.

I had a helluva time getting it into the ground, because it weighs several hundred pounds.

You may not know the answer yet, but where does the excess water go that runs off when you water
snow melts or it rains in the cavity you made for the cold frame?
This could easily revisit the mold issue or worse. I just haven't seen a picture or description
of the foundation/cavity for your cold frame in the ground.

 

[TheEmpireNeverEnded]

Snow is awesome. As it protects from winds as well as transpiration if deep enough
it keeps the root zone happy as it melts. Not a steady unwavering supply in our area
that remains all Winter, so you must still check the roots and water when needed.
You do not water below freezing, rather as with any season of the year, when necessary.
You'll have warm spells, most rainy I think, but not always.

I watered at least once/month last Winter on average, skipping no more than 6 weeks at the peak,
but if you see where I'm keeping mine, they are in a very dry location where no rain ever reaches.
https://www.bonsainut.com/threads/winter-storage-and-reusing-last-years-mulch.36569/
I'm just getting trees from around the South to the North side of the house for Winter.
Then in the next week , 10 days I'll start huddling them together under my sunroom then mulch them.

You may not know the answer yet, but where does the excess water go that runs off when you water
snow melts or it rains in the cavity you made for the cold frame?
This could easily revisit the mold issue or worse. I just haven't seen a picture or description
of the foundation/cavity for your cold frame in the ground.

Yes this makes sense. I'm going to have to keep a closer eye on soil dryness. I've been watering every two-ish weeks, because the mulch + lid has kept everything pretty damp (to my detriment ultimately, haha)

Hopefully excess water won't be too much of an issue. The base of the box is galvanized screen. Directly under the entire base is at least four inches of gravel (also a pain to haul), so it will hopefully just enter the ground normally. Now that the lid is up and there is rain in the forecast I will find out whether it drains well (fingers crossed).

 

[coh]

Yes this makes sense. I'm going to have to keep a closer eye on soil dryness. I've been watering every two-ish weeks, because the mulch + lid has kept everything pretty damp (to my detriment ultimately, haha)

Hopefully excess water won't be too much of an issue. The base of the box is galvanized screen. Directly under the entire base is at least four inches of gravel (also a pain to haul), so it will hopefully just enter the ground normally. Now that the lid is up and there is rain in the forecast I will find out whether it drains well (fingers crossed).

If it's going to rain, that is a time when I would cover the box. I don't think you need more moisture in there at this point! You could put a tarp or something over it to keep the rain out and allow
air exchange.

 

[TN_Jim]

I haven’t needed to water mine in over 6 weeks...they’re outside and it’s been rainforest weather...but still, I hope you’re not overwatering with your different circumstances

 

[TheEmpireNeverEnded]

If it's going to rain, that is a time when I would cover the box. I don't think you need more moisture in there at this point! You could put a tarp or something over it to keep the rain out and allow
air exchange.

You're right. Leaving it open during rain does now appear to me to be counterproductive as hell. A tarp is an excellent idea, thank you.

 

[rockm]

If it's going to rain, that is a time when I would cover the box. I don't think you need more moisture in there at this point! You could put a tarp or something over it to keep the rain out and allow
air exchange.

I split the difference. I have a two - foot and a half deep pit with two foot walls at ground level. I put a lean-to cover of 1x6 boards over the pit. The ends of the boards rest on an four foot tall inverted "U" support on one end and on the edge of the wall at the other. The slats fit closely enough together to shed most of the rain, but allow some to pass through. The open end allows brisk air circulation, but also some shelter from the worst winds. I remove the slats when snow is predicted. Snow is the best cover for overwintering trees. I've been doing this for a couple of decades now. Never had to water any of the trees, nor fight off rodents looking for shelter.

 

[Leo in N E Illinois]

I winter my trees in a below ground, under my back yard patio, unheated well house. Sounds cool, like a fall out shelter, eh?
It is concrete block and 70 year old concrete, all cracked and weeping moisture. Walls and floor are often wet, and even when dry the humidity is in the 90% range. During a rain storm, there is a river of water that drains into the old well bore hole. Obviously one of the reasons this well was decommissioned.

The first winter I used it, I had a similar mold problem and significant mortality as a result. About middle of winter I ran an extension cord and plugged in an inexpensive fan. The cheap mostly plastic fan you get at Menard's or Lowe's for less than $20, for $12 if you catch them on sale. Set the fan in the well house, pointing out and up at a back wall so that it wasn't blowing directly on any one group of trees. This circulates the air in the room enough that smaller leaves wave in the light breeze. I leave the fan on 24 hours a day, 7 days a week. Because the humidity is so high, the breeze does not significantly dry out the potting media, but it does keep the trunks and branches dry. Air movement also seemed to keep my roots healthier. Never had a problem since.

If you could set up a fan in your cold frame, that would also help. Don't know if that is feasible, but consider it.

Spray - Hydrogen peroxide, 3%, straight from the bottle you buy at your local big box pharmacy department. Spray that, undiluted on your trees, it will work as a surface sterilant, and help wash off the fungus. It will not harm the trees, it won't hurt the roots either. It probably won't bother the mycorrhizae. Hydrogen peroxide breaks down rapidly into water and oxygen, so there is no chemical residue to worry about. Pet and human safe. Give it a go. I actually use the concentrated product made for greenhouse use, Zertol, which is at 30% active, strong enough to burn human skin, and I dilute it to 3%. to use to clean leaves, trunks etc. The Zertol product is expensive, so I don't recommend you seek that out. I know others on here have recommended diluting hydrogen peroxide 3% to some lower concentration. In my experience there is no need to dilute below 3%. so as is the strength you get from the pharmacy is good enough. Dilute peroxide below 3 % and there is the risk you will drop below the concentration needed to actually kill off a surface infection of mold or mildew. You probably have one of the variants of powdery mildew or something similar to bread mold. A surface living yeast like mold.

 

[TheEmpireNeverEnded]

I winter my trees in a below ground, under my back yard patio, unheated well house. Sounds cool, like a fall out shelter, eh?
It is concrete block and 70 year old concrete, all cracked and weeping moisture. Walls and floor are often wet, and even when dry the humidity is in the 90% range. During a rain storm, there is a river of water that drains into the old well bore hole. Obviously one of the reasons this well was decommissioned.

The first winter I used it, I had a similar mold problem and significant mortality as a result. About middle of winter I ran an extension cord and plugged in an inexpensive fan. The cheap mostly plastic fan you get at Menard's or Lowe's for less than $20, for $12 if you catch them on sale. Set the fan in the well house, pointing out and up at a back wall so that it wasn't blowing directly on any one group of trees. This circulates the air in the room enough that smaller leaves wave in the light breeze. I leave the fan on 24 hours a day, 7 days a week. Because the humidity is so high, the breeze does not significantly dry out the potting media, but it does keep the trunks and branches dry. Air movement also seemed to keep my roots healthier. Never had a problem since.

If you could set up a fan in your cold frame, that would also help. Don't know if that is feasible, but consider it.

Spray - Hydrogen peroxide, 3%, straight from the bottle you buy at your local big box pharmacy department. Spray that, undiluted on your trees, it will work as a surface sterilant, and help wash off the fungus. It will not harm the trees, it won't hurt the roots either. It probably won't bother the mycorrhizae. Hydrogen peroxide breaks down rapidly into water and oxygen, so there is no chemical residue to worry about. Pet and human safe. Give it a go. I actually use the concentrated product made for greenhouse use, Zertol, which is at 30% active, strong enough to burn human skin, and I dilute it to 3%. to use to clean leaves, trunks etc. The Zertol product is expensive, so I don't recommend you seek that out. I know others on here have recommended diluting hydrogen peroxide 3% to some lower concentration. In my experience there is no need to dilute below 3%. so as is the strength you get from the pharmacy is good enough. Dilute peroxide below 3 % and there is the risk you will drop below the concentration needed to actually kill off a surface infection of mold or mildew. You probably have one of the variants of powdery mildew or something similar to bread mold. A surface living yeast like mold.

Thank you, this is extremely useful information regarding peroxide. I do have an external outlet pretty close to the box, so the fan is a possibility as well.

 

[TheEmpireNeverEnded]

I split the difference. I have a two - foot and a half deep pit with two foot walls at ground level. I put a lean-to cover of 1x6 boards over the pit. The ends of the boards rest on an four foot tall inverted "U" support on one end and on the edge of the wall at the other. The slats fit closely enough together to shed most of the rain, but allow some to pass through. The open end allows brisk air circulation, but also some shelter from the worst winds. I remove the slats when snow is predicted. Snow is the best cover for overwintering trees. I've been doing this for a couple of decades now. Never had to water any of the trees, nor fight off rodents looking for shelter.

Air circulation is definitely my missing component.

 

[TheEmpireNeverEnded]

I haven’t needed to water mine in over 6 weeks...they’re outside and it’s been rainforest weather...but still, I hope you’re not overwatering with your different circumstances

This is my fear. Since all of the rain we have been getting has not fallen on my trees, I am hoping that I did not overwater. I don't think that I've been vigilant enough about unburying and then checking each pot