Beating budrot... tactics and prioritising temp or RH?

[Budrottenjonny]

Hey all,

I'm just removed a bunch of growth that I discovered had early stage bud rot. Noticed a few, very yellow leaves and sure enough as I pulled them back I found mushiness setting in on two of the buds.

This is an auto Hindu Kush from Sensi Seeds - the third this year that's succumbed to Botyritis. She's been in a greenhouse in the day, brought inside at night but I live in a very 'moist' area and we've had some extra misty, rainy weather lately.

I've shifted her inside full time, under LEDs and with an oscillating fan on 18/6, to try and control the environment but whatever I do temps hover around 21-24 C / 69-75 F and between 65-75% RH.

I know these aren't ideal for managing bud rot. Outside in the day, the temp is waaaay high at the moment but RH is super low.

So in my dogged attempt not to let this one die, I'm wondering, is it better I keep her indoors where temp is down but RH higher - or outside where temp is up but RH down.

Anyone got an opinion or had success getting a chopped, infected plant over the line?

Thanks in advance.

 

[BigCube]

You have to get that rh down. Temp is good. You want your rh at 50 or less.

 

[Budrottenjonny]

You have to get that rh down. Temp is good. You want your rh at 50 or less.

Thank you - the tricky thing is, the only way to get the RH down is taking it outside, and temp is up around 30 C / 86 F.

Is that going to offset any of the benefits of reducing RH?

Even if I run the dehumidifier full on then RH inside doesn't drop below 60...

 

[BigCube]

Thank you - the tricky thing is, the only way to get the RH down is taking it outside, and temp is up around 30 C / 86 F.

Is that going to offset any of the benefits of reducing RH?

Even if I run the dehumidifier full on then RH inside doesn't drop below 60...

Then your dehumidifier isnt big enough

Outside would be better, outside it would love those temperatures as long as the rh is 50 or less.

Why is the rh so high? You have a pool in your house?

 

[Anthem]

Thank you - the tricky thing is, the only way to get the RH down is taking it outside, and temp is up around 30 C / 86 F.

Is that going to offset any of the benefits of reducing RH?

Even if I run the dehumidifier full on then RH inside doesn't drop below 60...

Unfortunately you have a problem that will not go away without further equipment or changes. The simple answer is you have to keep the RH below 50 percent period. In your case I would suggest 45 percent. Why, well you already have the spores in the grow area. So either you take the plant outside and risk the high temperatures and possible PM or you have to get a better dehumidifier.

 

[Budrottenjonny]

Unfortunately you have a problem that will not go away without further equipment or changes. The simple answer is you have to keep the RH below 50 percent period. In your case I would suggest 45 percent. Why, well you already have the spores in the grow area. So either you take the plant outside and risk the high temperatures and possible PM or you have to get a better dehumidifier.

Really helpful - got it - thank you.

I've got it permanently out the original grow area where it 'contracted' the bud rot (the greenhouse) but there's a chance it could have brought it inside.

This is one plant and given the spend so far, I can't justify a new dehumidifier.

I think all I can do is take it outside during the day where I'll get the RH right down and take it in at night before RH goes right up again, hoping that it doesn't spread and I can ID/remove any infected areas at harvest.

From what I understand, nothing's going to kill it and bringing RH down is just going to manage the problem, right?

The other option is to harvest early but AFAIK she's a good 3-4 weeks off and hasn't fully gone into bloom. I wonder if she will once she's suffered the trauma of the rot and snippage to remove it...

Also - sorry if it's newbie question (I am a newbie) but what's PM please?

 

[Anthem]

Really helpful - got it - thank you.

I've got it permanently out the original grow area where it 'contracted' the bud rot (the greenhouse) but there's a chance it could have brought it inside.

This is one plant and given the spend so far, I can't justify a new dehumidifier.

I think all I can do is take it outside during the day where I'll get the RH right down and take it in at night before RH goes right up again, hoping that it doesn't spread and I can ID/remove any infected areas at harvest.

From what I understand, nothing's going to kill it and bringing RH down is just going to manage the problem, right?

The other option is to harvest early but AFAIK she's a good 3-4 weeks off and hasn't fully gone into bloom. I wonder if she will once she's suffered the trauma of the rot and snippage to remove it...

Also - sorry if it's newbie question (I am a newbie) but what's PM please?

Powder Meldew

 

[BigCube]

PM aka WPM aka white powdery mildew.

A bitch to deal with even if you're an experienced grower. Recently I had an exhaust fan unplug itself, leaving the tent not exhausting for about 15 hours through its night cycle too. I was 3 or 4 weeks from harvest too. Sucked hard...
15 hours is all it took for the wpm to set in.

I dont fuck around with mold. I just got rid of the plants. And bleached the shit out of everything.

Low RH and good airflow are what you want. If your airflow sucks, the tent/room could be 45% but you could have pockets of 70% or more in the dense foliage and touching buds.

 

[FourthCity]

Hey all,

I'm just removed a bunch of growth that I discovered had early stage bud rot. Noticed a few, very yellow leaves and sure enough as I pulled them back I found mushiness setting in on two of the buds.

This is an auto Hindu Kush from Sensi Seeds - the third this year that's succumbed to Botyritis. She's been in a greenhouse in the day, brought inside at night but I live in a very 'moist' area and we've had some extra misty, rainy weather lately.

I've shifted her inside full time, under LEDs and with an oscillating fan on 18/6, to try and control the environment but whatever I do temps hover around 21-24 C / 69-75 F and between 65-75% RH.

I know these aren't ideal for managing bud rot. Outside in the day, the temp is waaaay high at the moment but RH is super low.

So in my dogged attempt not to let this one die, I'm wondering, is it better I keep her indoors where temp is down but RH higher - or outside where temp is up but RH down.

Anyone got an opinion or had success getting a chopped, infected plant over the line?

Thanks in advance.

Low RH and good airflow are what you want. If your airflow sucks, the tent/room could be 45% but you could have pockets of 70% or more in the dense foliage and touching buds.

I agree with @BigCube about the airflow. Personally I think airflow is the most important factor in preventing bud rot, even high humidity can be manageable if the airflow is sufficient. If you can, add a few more fans and and place them at different heights, you definitely need more than one.

 

[Anthem]

I agree with @BigCube about the airflow. Personally I think airflow is the most important factor in preventing bud rot, even high humidity can be manageable if the airflow is sufficient. If you can, add a few more fans and and place them at different heights, you definitely need more than one.

Adding fans is also going to do a great job of moving the botrytis spores. The key is to keep the spores from becoming by lower the RH below 50. 50 is the beginning of the benchmark were the spores will not become active. Right now they are floating in your grow and they will attack your largest cola's first. Air movement is great and can be used to assist but you have to get the RH down to keep the spores from becoming active. Just moving the air will not stop the spores from becoming active.

 

[Anthem]

I had an associates that visited an award winner grow recently. While they keep their RH at 75 and Temperatures at 80. They also required individuals to shower, put on sterile clothing, shoe coverings and hair coverings before entering the grow. While this is a perfect mold growing environment the grow was based on not letting the spores into the grow room in the first place. Once the spores are in the grow it becomes more difficult to control them from becoming active with RH over 50.

 

[RippedTorn]

50 is the beginning of the benchmark were the spores will not become active.

That's not accurate. If neo pot growers are going to obsess over numbers, and throw around guidelines based on numbers, they should actually mean something.

There's more moisture in the air at 50rh 80 degrees than there is at 50rh 60 degrees. It's called relative humidity because it's relative.. And it's a useless metric for growing plants. I've been waiting for this community to pick up on this for a while but I think I'll just start being ranting about it:

CANNABIS GROWERS, STOP MAKING POT LOOK STUPID. Plants are not sweaty humans, they don't care about RH at all. You need RH, barometric pressure and temperature to calculate absolute humidity, an ALMOST useful number. Now you have to reference that number with the Brix ° of the plant to find out how much moisture is in the powdery mildew food source (and you also have to know how much moisture the powdery mildew prefers).

Half assed science is worse than no science. Stop it. Go do some kindergarten level science and put a hygrometer in a sealed jar. Put it in the sun. Then put it in the fridge. The number on the magic science thingy changes, does that mean the moisture in the jar is changing?

No wonder fungicides are so common these days! The modern pot grower refuses to use his brain! 50%rh is two different moisture levels at two different temperatures!

 

[Anthem]

That's not accurate. If neo pot growers are going to obsess over numbers, and throw around guidelines based on numbers, they should actually mean something.

There's more moisture in the air at 50rh 80 degrees than there is at 50rh 60 degrees. It's called relative humidity because it's relative.. And it's a useless metric for growing plants. I've been waiting for this community to pick up on this for a while but I think I'll just start being ranting about it:

CANNABIS GROWERS, STOP MAKING POT LOOK STUPID. Plants are not sweaty humans, they don't care about RH at all. You need RH, barometric pressure and temperature to calculate absolute humidity, an ALMOST useful number. Now you have to reference that number with the Brix ° of the plant to find out how much moisture is in the powdery mildew food source (and you also have to know how much moisture the powdery mildew prefers).

Half assed science is worse than no science. Stop it. Go do some kindergarten level science and put a hygrometer in a sealed jar. Put it in the sun. Then put it in the fridge. The number on the magic science thingy changes, does that mean the moisture in the jar is changing?

No wonder fungicides are so common these days! The modern pot grower refuses to use his brain! 50%rh is two different moisture levels at two different temperatures!

Last time I checked we do not grow cannabis in the refrigerator. 50 percent was based on the temperature range the OP provided.

 

[FourthCity]

Adding fans is also going to do a great job of moving the botrytis spores. The key is to keep the spores from becoming by lower the RH below 50. 50 is the beginning of the benchmark were the spores will not become active. Right now they are floating in your grow and they will attack your largest cola's first. Air movement is great and can be used to assist but you have to get the RH down to keep the spores from becoming active. Just moving the air will not stop the spores from becoming active.

I agree you want to keep spores to a minimum and proper rh and temp is important, but with enough airflow you can even stop active spores from colonizing on your plants. My point is that airflow is not the only important element to control but it may be the only one with the power to stop bud rot on its own.

 

[Anthem]

I agree you want to keep spores to a minimum and proper rh and temp is important, but with enough airflow you can even stop active spores from colonizing on your plants. My point is that airflow is not the only important element to control but it may be the only one with the power to stop bud rot on its own.

Active Air Flow alone will not stop the spread once it has already take hold.

 

[FourthCity]

Active Air Flow alone will not stop the spread once it has already take hold.

Agreed 100%.

 

[Budrottenjonny]

Really appreciating your insight - and I can see that there's rarely a clear-cut answer that everyone can agree on. All good.

I'd love your opinion on what I do next. I've attached some photos so you can see a bit more what's going on.

At the site of where I removed the buds, I can see there was a minor split in the main stalk and it looks like there's some mold growth there - maybe also at the site of the pruning. I'm wondering if it can get into the plant and spread that way or whether it's just transmitted by airborne spores?

I also just pulled two very thin, spindly, brown leaves from the buds either side of the site - they were so thin and easy to pull out I'm fairly certain they show some kind of spread even though there's no other noticeable symptoms on the buds themselves... I guess it's starting from the inside out...

I've also noticed some brown discolouration appearing on the stalk,

It's heart breaking because she's just about to go into the final stage of flowering, was looking super healthy and this is the only grow I'll get in this year! Bah!

We live in a super humid area - it drops to 30% RH for a few hours a day, otherwise it can be as high as 80% for most of the time (acknowledging the flaws of RH as brought up here). I'm just going to be rushing her in and out all the time and that's just not feasible with work, kids etc.

Airflow indoors is pretty good now - that's fixed. Humidity will be harder - I'm finding that the inside RH seems to mirror outside and it's almost impossible to get things down far enough. I'm not going to get a good dehumidifier without pissing my wife off beyond what's tolerable.

So the obvious options that I can see are:
- bin it now.
- cut out more of the buds laterally around the site and see keep an eye on the spread to see how far I can take her.
- cut her top off, just below the site and see if she continues to mature.
- harvest her now and dry her quickly, make the most of what might be left.

What would you do under the circumstances?

Bearing in mind there are no other plants to be infected and this is a spare room rather than a dedicated grow space that needs to be clean for the next grow.

 

[Edinburgh]

My plants are 58 days old, 35 of those days have been 90f+ with dew points in high 70s, an ac and dehumidifier can only do so much, not many strains can take that kind of punishment, allso there is no dirt to be found, got last bag of premix for my bubblegum grow, but on top of all that my plants are really potbound someone gave me 2 beans and thought they would be smallish, but to avoid bud rot you have to keep the humidity down mine has been ok at 50 55%, i will probably defoaliate slowley as the flower matures, most definitely not my best but never took this grow seriously thats bad, should have just grew 1 plant but live and learn, try your best to keep your rh from jumping around to much air conditioning can only do so much but definitely helps a de humidifier cant hurt either.

 

[Kanzeon]

Is it at all possible to increase the heat inside? If you can get it to 78-83, your RH would be right on.

Both botrytis and PM are brought on by the plant being in an environment without the optimal vapor pressure deficit. An abundance of humidity in standing air tends to bring on botrytis, and too little humidity can let PM set in. So both are brought on by a combination of suboptimal temperature, airflow, and RH.

Micronized sulfur sprayed on the PM-effected plants in flower helped me until I could get the room dialed in better. It'll inhibit PM, but you'll need to rinse the buds before smoking them. Which, given the PM, you should do anyway.

 

[dward]

Light a fire if u leave the plant in the greenhouse with the door open and have a chimney to extract the smoke a little it will warm up and decrese the humidity.
the spores will only spread in wet conditon so kill em with heat.
Other ways to sort the problem is less watering! and not sure about nutrients but minerals from nettle compost tea and silica.