Two weeks from harvest - Mold or mildew? What should I do?

[Landracey]

Hello, Im a first time grower from the UK. Plants are close to harvest, but I need some advice about what to do about this F1 hybrid. It has developed mould, or mildew (I don't know which).

Should I quarantine from other plants? (Difficult as I only have one HPS light + grow tent).
Should i harvest early?
Should I try to treat it, or is it too late given I'm in 9th week of flower?

I would be grateful for the advice of more experienced growers. Thanks.

 

[Wrecked11]

I don't know much about mold contamination but that doesn't look good i would pull it if it were me. There's no mold on any others in the room?

 

[Roy Growin]

If it is just a little on the surface of the leaves you might get away with cutting off the worst of it and spraying with citric acid or H2O2 to kill off any remnant spores
If the mould has made plant tissue mushy there is nothing you can do except try to salvage whatever is still clean

 

[KeithLemon]

I would spray with citric acid as Roy stated.

 

[Vegan4life]

What is the humidity? Do you have plenty of air flow and air exchange? Do you have fans in the grow tent? Exhaust?

 

[Landracey]

What is the humidity? Do you have plenty of air flow and air exchange? Do you have fans in the grow tent? Exhaust?

Hi, in fact I have no grow tent, more like a grow room, and I only have 5 plants so the need for air exchange and fans is minimal. I just open the windows. I move them into the bedroom at night so they get some air exchange. I also leave the window open, and I think that is how the spores contaminated the F1 hybrid, which was closest to the window. The four landrace plants are doing fine, it is just the F1 hybrid that is contaminated.

 

[Landracey]

If it is just a little on the surface of the leaves you might get away with cutting off the worst of it and spraying with citric acid or H2O2 to kill off any remnant spores
If the mould has made plant tissue mushy there is nothing you can do except try to salvage whatever is still clean

Thanks Roy, and also Keith Lemon. I have cut away the bottom branches where the worst of it was and sprayed with citric acid and cooking vinegar, then dried quickly with a fan to avoid bud rot. Should I isolate from the other plants, or just monitor as the four landraces (Kwazulu Natal, Afghan Kush) are healthy?

 

[Landracey]

Dehumidifier as the English autumn gets really damp. Hovering around 50%

What is the humidity? Do you have plenty of air flow and air exchange? Do you have fans in the grow tent? Exhaust?

I set the dehumidifier at 40% but it never seems to go below 50% - damp English autumn!

 

[KeithLemon]

Thanks Roy, and also Keith Lemon. I have cut away the bottom branches where the worst of it was and sprayed with citric acid and cooking vinegar, then dried quickly with a fan to avoid bud rot. Should I isolate from the other plants, or just monitor as the four landraces (Kwazulu Natal, Afghan Kush) are healthy?

Yes, move the affected plant away from the other nonaffected plant. as soon as you can. It will spread and it can be fast. I hope you contain it.

 

[Landracey]

Thanks, I will do as you recommend and keep you updated!

 

[Vegan4life]

Dehumidifier as the English autumn gets really damp. Hovering around 50%

I set the dehumidifier at 40% but it never seems to go below 50% - damp English autumn!

I grow in a humid environment as well... Lucky if I can keep my grow space at 60% humidity. I keep lots of airflow going 24/7. Keep a fan blowing on the plants to help keep the leaves dry as they transpire.

 

[SmokingWings]

I think that is how the spores contaminated the F1 hybrid, which was closest to the window.

Maybe the spore came in through the screen or it might have been floating in the air and landed on your shirt and you brought it inside. Powdery Mildew is a fact of life when growing inside or out. Can't really place the blame anywhere for the spore.

The four landrace plants are doing fine, it is just the F1 hybrid that is contaminated.

If one plant in the room had mildew then believe that all the others are contaminated. The mildew has not grown enough to be visible but believe that it is there. Treat all the plants whether you see mildew on them or not.

I have cut away the bottom branches where the worst of it was and sprayed with citric acid and cooking vinegar

The link below is to the recipe for one of the best citric acid sprays. The author has a second recipe for a slightly weaker version but the recipe in the link does a great job. It is also easy to reduce the amount of spray if you only want to mix up a liter or half-liter at a time.

https://www.420magazine.com/community/threads/thrips.512473/post-5519939

Don't know if you used Malt or "spirit" vinegar which are common names popular vinegars in England. Over here the recommended vinegar is often Apple Cider Vinegar. There are plenty of recipes for suggested dilutions of vinegar and water so just a quick search will do.

then dried quickly with a fan to avoid bud rot.

Most likely if you find Bud Rot the plant was infected weeks ago. Drying is good because it will keep it from starting or slow down if it has started. Keep checking the buds because there does not seem to be any way to stop it once it begins to grow.

 

[Landracey]

Maybe the spore came in through the screen or it might have been floating in the air and landed on your shirt and you brought it inside. Powdery Mildew is a fact of life when growing inside or out. Can't really place the blame anywhere for the spore.


If one plant in the room had mildew then believe that all the others are contaminated. The mildew has not grown enough to be visible but believe that it is there. Treat all the plants whether you see mildew on them or not.


The link below is to the recipe for one of the best citric acid sprays. The author has a second recipe for a slightly weaker version but the recipe in the link does a great job. It is also easy to reduce the amount of spray if you only want to mix up a liter or half-liter at a time.

https://www.420magazine.com/community/threads/thrips.512473/post-5519939

Don't know if you used Malt or "spirit" vinegar which are common names popular vinegars in England. Over here the recommended vinegar is often Apple Cider Vinegar. There are plenty of recipes for suggested dilutions of vinegar and water so just a quick search will do.


Most likely if you find Bud Rot the plant was infected weeks ago. Drying is good because it will keep it from starting or slow down if it has started. Keep checking the buds because there does not seem to be any way to stop it once it begins to grow.

Thank you SmokingWings for your excellent advice and comment. I decided a few days later to just harvest the F1 early and wash it in H202 as recommended by outdoor growers such as Jorge Cervantes. I found mould on the lower branches of one of the Sativas as well. So I cut those branches away and washed them too before trimming and drying. I am now thinking I should harvest the others as it is finally dry and sunny outdoors and they are 64 days from flipping. Do they look ready to you? Thanks.

 

[Roy Growin]

Hard to tell, but you appear to have a mite problem too so when you do harvest, a H2O2 rinse will clear any bugs or poop as well as burning off any mould spores

 

[SmokingWings]

I found mould on the lower branches of one of the Sativas as well. So I cut those branches away and washed them too before trimming and drying. I am now thinking I should harvest the others as it is finally dry and sunny outdoors and they are 64 days from flipping. Do they look ready to you?

I am not there to see them in person so it is hard to tell if they are ready for harvest.

As for the mold on the lower branches there is a bit of difference between mold and mildew. Something like Powdery Mildew, if it is not yet deep into the buds, can be treated with a spray and no need to trim until the plant is finally finished.

Some of the molds like the infamous Bud Rot, which usually starts at the top of the plant, should be taken care of right away and that includes removing the infected buds and cutting out the mold areas. Bud Rot is literally eating the plant alive. The rest of the buds that were not showing signs will need an intensive bud washing.

 

[Landracey]

I am not there to see them in person so it is hard to tell if they are ready for harvest.

As for the mold on the lower branches there is a bit of difference between mold and mildew. Something like Powdery Mildew, if it is not yet deep into the buds, can be treated with a spray and no need to trim until the plant is finally finished.

Some of the molds like the infamous Bud Rot, which usually starts at the top of the plant, should be taken care of right away and that includes removing the infected buds and cutting out the mold areas. Bud Rot is literally eating the plant alive. The rest of the buds that were not showing signs will need an intensive bud washing.

Thanks for letting me know about this. I don't want to rush to harvest if it is PM and controllable. I think it is because the lower buds only were affected, and it is whiteish coloured, but hard to tell. Unfortunately I only have one dehumidifier so I will have to hang them in one room. Maybe I will stagger the harvest so that I can jar the dried buds that were affected before harvesting the upper parts of the remaining plants. That's about as quarantined as I can make it. FIngers crossed.