Firs grow, need help diagnosing problem.

This is my first outdoor grow. I'm in the 5th week of flowering. I've been covering the plants with black plastic overnight to induce flowering but noticed that some form of disease is beginning to attack the tops of all my buds. I tried researching to find out what it is but came up with nothing. It is not rust mites since I used 200x microscope and no pests were found. I suspect it is blight or rust fungus or botrytis but I can't be sure without your help. I started covering for only a couple of hours a night and running fans day and night.
My entire crop is at danger of being wiped out so I would really appreciate some advice.
Here are some pics:

Might be bud rot. Putting a plastic bag over them is not a good idea at all. The high humidity was almost certain to cause white powder mildew or bud rot or mold

The color is weird though so im not certain. All i can say for sure is putting that bag over is gonna give you problems

Yeah, that's what I figured. Would e nice to know what is causing this though.

I don't see how your going to fix the issue

you can t stop covering it now or itll go back into veg

you cant continue to cover it or itll just get worse, if it is indeed rot

a picture of the entire plant would help

maybe you could cover it only for a couple hours until the sun falls and then un cover it for the remaining night to minimize the covering time

aside form that

they look magnesium def

the twist and cupping is classic magnesium def, which would be treated with Epsom salt

1/2 tsp per gallon is a safe dose

Thank you for your diagnosis; however, I heard that I cannot use epsom salts in organic soil since they will kill any beneficial bacteria. Is this true and is there another way to add Mg?

im4satori said:

I don't see how your going to fix the issue

you can t stop covering it now or itll go back into veg

you cant continue to cover it or itll just get worse, if it is indeed rot

a picture of the entire plant would help

maybe you could cover it only for a couple hours until the sun falls and then un cover it for the remaining night to minimize the covering time

aside form that

they look magnesium def

the twist and cupping is classic magnesium def, which would be treated with Epsom salt

1/2 tsp per gallon is a safe dose

Click to expand...

Thank you for your diagnosis; however, I heard that I cannot use epsom salts in organic soil since they will kill any beneficial bacteria. Is this true and is there another way to add Mg?

that's not at all true

go into the organic section and you will find they all use Epsom

at low salinity Epsom wont affect your biology anymore than a tap water with a small amount of mineral in it

its when the salinity becomes to strong that itll affect your biology .. so repeated salt fertilizer inputs at a high EC/ppm will reduce the biology but a safe amount of Epsom salt is like gold

Great, thanks man.