Serious mold problems

[Valahnuk]

Hi.

I'm in some desperate needs for some advice to how I can stop my freshly harvested tobacco from getting moldy during color curing

Just after 1 1/2 to 2 weeks after harvest, the mid stem are starting to get moldy. It doesn't matter which temperature or humidity it is, i've tried to hang them outside, in my basement where I usually color cure my tobacco, and in my house where the humidity is below 55% RH.
Some leaves have even dried so fast that they're still a bit green, but even those leaves are getting mold on the mid stem.

I don't know what to do with the rest of my tobacco that is still growing in my garden. They are already ripe but if I harvest them, they also going to get moldy.
I've tried to treat the moldy mid stems with hydrogren peroxide, but the day after it's was 5 times as worse than the day before. So that doesn't help at all.
I just don't know what do to.

This is my third year that I'm growing my own tobacco and I have never had this problems with mold before. The only times I've had some problems with mold has been later in the autumn when the leaves are fully color cured. But not this early.

I just checked my leaves that is color curing right know. they were harvested just about a week so ago, and there's already some white mold growing on the mid steams, and the leaves have just turned from green to yellow.
I don't understand why they are getting moldy so damn fast? The humidity has been about 60-65% RH and I also have a big fan that is running 24/7. There's about 1-2 inch space between every leaf so they are not touching each other. Temperature has been around 70F. I tried to increase the temerature to around 80F but same thing happens. I Doesn't matter.

This is just crazy.

What should I do?

 

[Knucklehead]

Could you post some photos?

 

[deluxestogie]

Could you post some photos?

And, how much leaf are you having difficulty with? What varieties?

Bob

 

[Valahnuk]

Could you post some photos?

The first picture is on the leaves that was most affected, so I fast dried all those leaves in the oven.

Second and third picture are on some leaves that are color curing right now.
Yesterday when i checked, there was no mold on them so this have appeared just over night.
And as I said in the first post, even the leaves that have dried green, already has some mold developing on the mid rib as you can se in third picture. That leaf is almost dry, except the mid rib.

 

[Valahnuk]

And, how much leaf are you having difficulty with? What varieties?

Bob

More or less on every leaf from the first harvest. A total amount of around 0,8lbs of tobacco.
The varieties are KY17 and TN90.

I have only harvested smaller batches after that, maybe 10-15 leaves at the time. But just a week or so after they have been color curing, white mold starts to develop on the parts of the mid rib that has dried. And it grows extremely fast.

 

[deluxestogie]

If you have seedling heat mats, you can accelerate the stem drying by stacking the leaf on them. Direct sunlight will inhibit mold growth. The longer the leaf matures on the plant, the lower the stem moisture will be when harvested. I have found some burley's to frequently exhibit mold growth on the leaf stems after curing. But if the lamina is in low case or dry, the mold does not spread to the leaf surface. Another approach is to frog-leg the leaf, though that makes it troublesome to hang and handle.

Bob

EDIT: If you raise the ambient temperature by 20°F, that will drop the relative humidity in half.

 

[Knucklehead]

The first picture is on the leaves that was most affected, so I fast dried all those leaves in the oven.

Second and third picture are on some leaves that are color curing right now.
Yesterday when i checked, there was no mold on them so this have appeared just over night.
And as I said in the first post, even the leaves that have dried green, already has some mold developing on the mid rib as you can se in third picture. That leaf is almost dry, except the mid rib.

How do you consume your tobacco? Cigar, cigarettes, or smokeless like snus or chew?

 

[GreenDragon]

Airflow helps prevent mold. Try adding a fan to circulate the air.

 

[Valahnuk]

If you have seedling heat mats, you can accelerate the stem drying by stacking the leaf on them. Direct sunlight will inhibit mold growth. The longer the leaf matures on the plant, the lower the stem moisture will be when harvested. I have found some burley's to frequently exhibit mold growth on the leaf stems after curing. But if the lamina is in low case or dry, the mold does not spread to the leaf surface. Another approach is to frog-leg the leaf, though that makes it troublesome to hang and handle.

Bob

EDIT: If you raise the ambient temperature by 20°F, that will drop the relative humidity in half.

Yes I have been thinking about splitting the mid rib in half to speed up the drying process.
I just don't know if that is a good idea because the first time I tried that in 2018, I experienced that the only leaves that I had mold issues with, was on the ones that had splitted mid rib. It sort of became like an open wound.

And with this aggressive mold issuse I have right now may even make it even worse. I don't know.

 

[skychaser]

TN 90 and KY 17 should both turn yellow of the stalk. They color easily. Don't pick them until they have started to change color or have yellowed on the plant. To cure leaf (get the green out) you want high humidity and heat. 90-95 degrees is ideal with 80%+ humidity for curing. Green leaf won't mold because the leaf is still alive. But once it starts to become fully yellow or starts to turn brown, it is dead leaf and mold can set in very fast. At that stage you want to drop the humidity down as much as you can, increase the air flow around it and get it dried as quick as possible. Dry it until the stem snaps like a dry twig. Stems hold a lot of water and stem mold is pretty common if it's not bone dry. A little stem mold won't hurt the leaf itself and most of us throw them away anyways. Your green leaf was dried to fast and isn't good for much now. It is showing mold because it is now dead and the humidity is high enough for mold to take hold.

 

[Valahnuk]

TN 90 and KY 17 should both turn yellow of the stalk. They color easily. Don't pick them until they have started to change color or have yellowed on the plant. To cure leaf (get the green out) you want high humidity and heat. 90-95 degrees is ideal with 80%+ humidity for curing. Green leaf won't mold because the leaf is still alive. But once it starts to become fully yellow or starts to turn brown, it is dead leaf and mold can set in very fast. At that stage you want to drop the humidity down as much as you can, increase the air flow around it and get it dried as quick as possible. Dry it until the stem snaps like a dry twig. Stems hold a lot of water and stem mold is pretty common if it's not bone dry. A little stem mold won't hurt the leaf itself and most of us throw them away anyways. Your green leaf was dried to fast and isn't good for much now. It is showing mold because it is now dead and the humidity is high enough for mold to take hold.

The leaves that I harvest are almost completely yellow so I'm not picking them too early.

But the problem is that the leaves barely have time to start to shift from yellow to brown before mold begins to form. if only a tiny piece of the midrib or the smaller veins has dried, it starts to mold on it. And by the time that the whole leaf has shifted from yellow to brown the whole mid rib looks like a stick of cotton candy.

And if I lower the humidity the lamina dries too quickly but the mold on the mid ribs keeps growing.

This is not the first time i grow tobacco, so I have a decent perception of how it all works. But this mold issue is something else. I'ts so aggressive and develop so damn fast that no matter how I regulate the humidity and temperature, the leaves do not have time to reach the brown stage before the midrib is covered with mold.

 

[Valahnuk]

Airflow helps prevent mold. Try adding a fan to circulate the air.

As i wrote in my first post I already have a fan that is running constantly, and there is plenty of space between the leaves so they are not touching each other

 

[deluxestogie]

When I spoke of frog-legging a leaf, I mean the total removal of the thickest 2/3 to 3/4 of the stem length, leaving only about 1/3 to 1/4 of the stem length (the thinnest portion) joining the tip of the leaf halves.

Bob

 

[Valahnuk]

When I spoke of frog-legging a leaf, I mean the total removal of the thickest 2/3 to 3/4 of the stem length, leaving only about 1/3 to 1/4 of the stem length (the thinnest portion) joining the tip of the leaf halves.

Bob

Okay, remove most part of the stem immediately after harvest, maybe that would be worth a try.

Do you think I can leave a small part of the top part of the stem (or bottom depends how you see it) so I still can hang the lamina, or do you think that it will start to mold?

 

[skychaser]

I see now that you joined here over 3 years ago, so you are not new to this. Mold can be a real bitch! It was one of my biggest problems until I found the method of curing and drying that worked best for me in my climate. My first couple years I was picking too soon so curing was taking too long and was very uneven. And I remember all too well those cotton candy looking stems that literally grow overnight.

Getting rid of as much stem as you can is a good idea. As much as you can and still leave it attached enough to be manageable. And try to get the humidity below 60%. Below that mold has a hard time growing. You can stalk cut and hang Burleys. But I usually string my TN 90 because it takes up less space and I think it makes a better looking finished leaf. By the time I pick, it is usually already 90% or more yellowed so it has essentially already color cured on the plant. I hang it outside in the shade and let it wilt down, then I go right to the drying stage. I live in a semi-arid climate and it is usually still hot and dry at picking time. Humidity here July through September is usually in the teens. We were at 7% one day last week. So drying is pretty easy for me. I flash dried a green leaf or two during my learning curve years too.

If your leaf is yellow try skipping the usual curing stage and go right to drying it. Mine always comes out a nice light golden brown. I think curing and drying is the most difficult part of producing your own tobacco for most people. Not that it is technically hard. It isn't. But finding what works best for you can be. We all have different climates and different resources to work with. It may be hot and dry where I live at harvest time, but where you live it may be cool and humid. Or hot and humid, or somewhere in between. And a person may be doing it their basement, or attic, or in a shed or barn. Conditions vary for all of us and we can only work with what we have available. But once you find what works for you, it seems pretty easy.

 

[Valahnuk]

I see now that you joined here over 3 years ago, so you are not new to this. Mold can be a real bitch! It was one of my biggest problems until I found the method of curing and drying that worked best for me in my climate. My first couple years I was picking too soon so curing was taking too long and was very uneven. And I remember all too well those cotton candy looking stems that literally grow overnight.

Getting rid of as much stem as you can is a good idea. As much as you can and still leave it attached enough to be manageable. And try to get the humidity below 60%. Below that mold has a hard time growing. You can stalk cut and hang Burleys. But I usually string my TN 90 because it takes up less space and I think it makes a better looking finished leaf. By the time I pick, it is usually already 90% or more yellowed so it has essentially already color cured on the plant. I hang it outside in the shade and let it wilt down, then I go right to the drying stage. I live in a semi-arid climate and it is usually still hot and dry at picking time. Humidity here July through September is usually in the teens. We were at 7% one day last week. So drying is pretty easy for me. I flash dried a green leaf or two during my learning curve years too.

If your leaf is yellow try skipping the usual curing stage and go right to drying it. Mine always comes out a nice light golden brown. I think curing and drying is the most difficult part of producing your own tobacco for most people. Not that it is technically hard. It isn't. But finding what works best for you can be. We all have different climates and different resources to work with. It may be hot and dry where I live at harvest time, but where you live it may be cool and humid. Or hot and humid, or somewhere in between. And a person may be doing it their basement, or attic, or in a shed or barn. Conditions vary for all of us and we can only work with what we have available. But once you find what works for you, it seems pretty easy.

I have done it the same way as i did in 2018 and 2020, and those years worked fine. No mold during color curing.

But thank you for the information.

I think I will remove the mid rib on all the leaves that are currently color curing, and quick dry them seperately in the oven, then just let the lamina colorcure on it's own.

I might even move them to another place so I can sanitize the entire room in my basement with an anti-mold agent. Don't know if that has any effect on possible mold spores that's in the room but i might be worth it.

Then start over from scratch again.

And when i harvest new leaves I'm thinking maybe I should stack the leaves for the first week or so to speed up the color curing even more.
Then remove the mid ribs and then just hang the lamina-part of the leaves.

I believe I need a high humidity while color curing just the lamina, otherwise it will probably dry too quickly when there's no mid rib left?

 

[deluxestogie]

quick dry them seperately in the oven

Don't go above ~54°C in the oven, or there will be no more color-curing.

Bob

 

[Valahnuk]

Don't go above ~54°C in the oven, or there will be no more color-curing.

Bob

I'ts only the stems I quick dry in the oven, not the lamina