Circular, brown necrotic spots on plant leaves. Need help

The plant is growing in a 10 gallon pot, outdoor. It is about 4 weeks into flowering and there are strange circular necrotic spots forming on some of the leaves. They start small and get bigger until they get crispy and wither away. It looks kind of like a tree ring.

Perhaps you got some water on the leaf which can act as a magnifying glass and burn the leaves.I might be wrong but since no one else has answered yet I thought I'd throw in my opinion. Looks healthy apart from those blotches.

I thought about that myself, but I'm pretty careful to only water the base of the plants.

I guess that is a possibility though. Thanks for the reply.

I myself am very careful about only watering at the bases but often enough I see a droplet of water on a leave that must have came from the pouring jug as I lift it out the way.

I am surprised no one else has commented on what it may be, either I am correct or no one that knows better has seen yet.

Keep bumping a few times a day till you get a more experienced answer to be safe.

Hopefully is it something as simple as stray water droplets, but I'm doubtful.

At this point in the season I'm worried about the possibility of mold. Having dead/dying tissue on your plants is bad news.

I'll definitely keep an eye on this thread, as well as researching for other possibilities. I really do appreciate you taking the time to offer your advise.

I just noticed something in your first post I should have noticed right away, you are growing outdoors. There should not be a problem with water contacting the plant (in veg at least) outdoors as that is the natural environment. Indoor lighting is so close and hot, that's when the burning occurs.

Best to keep your plant dry, as much as possible anyway.

But that dead tissue, don't just take off whole leaves. That is a waste. Cut out any dead and decaying matter and leave as much green on the leaves as possible and you will minimise and harm. If it spreads, then look into it further. It doesn't look like a deficiency as such to me. Looks more like burns, but I am no way experienced in advising on deficiencies. Just my opinion.

View attachment 2797403

I've actually been cutting the dead spots away from the leaf, without completely removing it in an attempt to not shock the plant too much.

I think I'll just keep a close eye on it. They should be finishing up within 3 weeks to a month anyway. As long as I can keep it under control I'll be alright.

I'll keep an eye on this thread, as well as update it if I come up with a diagnosis.

I have found out what the problem is. After using multiple search engines i found a picture of a leaf that looks exactly like mine. Its called late blight, a fungus that commonly affects tomato plants. It is also referred to as "yellow leaf spot disease". I'll have to invest in a good fungicide and hope for the best.

I was thinking leaf spot fungus myself. You may want to hold off with the fungicide since you are 4 weeks into flower though. Good luck and enjoy the weed !

Foothills said:

I was thinking leaf spot fungus myself. You may want to hold off with the fungicide since you are 4 weeks into flower though. Good luck and enjoy the weed !

Click to expand...

I don't really want to have to spray my plants with anything, but it worries me that this fungus is causing dead tissue to form on my leaves. That's just inviting bud rot IMO.

I'm glad that I at least know what I'm dealing with.