RUSTY LEAVES! What could it be?

Hey everyone!!!

New member here, and I’m having issues with my plant 5 weeks in. I was wondering if anyone can help?? I’m currently growing in a 5 gallon pot Gorilla Glue (autoflower) and I’m using a “300 watt” UFO LED light around 18 inches from the plant. The temp on average is between 77-87 degrees (depending on the point of day), with my humidity running between 50%-60% on average. I recently started using a 24 hour light schedule for the plant, originally was doing 18/6.

Do pictures look like a pH issue, mineral deficiency, heat issue, underwatering, etc.?
If anyone could help that would be awesome, i’m just worried I’ll lose the plant eventually.!

  • STRAIN: Gorilla Glue #4
  • Method: A Pot for Pot kit, soil
  • Vessels: 5 gallon pot
  • PH of Water: Its been around 6-7
  • Indoor
  • Light system: 300 watt ufo LED
  • Temps; Day (84-87), Night (76-84)
  • Humidity; 50-60%
  • Ventilation system; Carbon filter+ inline fan, clip fan
  • AC in living room when temps get above 86, and humidifier inside tent
  • Co2; no


Welcome to the forum.

What are you feeding at this time?

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thanks for the reply! I’m not doing any feeding at the moment. I purchased a kit from A Pot for Pot which recommended I get seeds from this bank! here’s a link to the kit I purchased that came with a premixed soil etc.

It seems the soil contains everything thats needed for a grow (according to the site).
I also noticed this coincidentally started happening more and more as I began using filtered water from my BRITA for my watering. I started filtering my water for my humidifier because deposits were being left on the leaves, however there are no more deposits now. As a result I began using filtered water for my grow as well.

I am not familiar with the properties of the A Pot for a Pot soil. It could be one of a number of things. Improper pH, cal or mag deficiency, or a phosphorous excess. I doubt it is an excess in a cannabis soil that hasn’t been supplemented.

Do you know what your PPM is?

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I do not know what my PPM is, i’m going to get a tester today. I have a soil pH tester coming in soon as well. In the meantime I think I’m going to water the plant with the tap water (how i originally did unfiltered), correct the pH of it first of course, and see if that makes a difference.

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what pH would you recommend for the watering by the way?

6.3 to 6.8. If you use reverse osmosis or distilled water it should be fine and won’t impact the pH of your soil, which should be on track if you have not been feeding.

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better off with a digital pen that you can monitor soil and liquid. Bluelab makes a soil meter that’s pretty good but nothing else that I’m aware of is worth $.02. It makes me nervous to see “PH at 6 to 7” because that’s simply not good enough.

Also; would be good to find the actual wattage draw of that UFO light: more than likely it’s 100 watts and insufficient to flower a plant properly. Just FYI.


Ive been adding several drops (2-3) of pH down to my watering can each time I water. I might be possibly doing an incorrect pH since i’m just visually aiming for a pH rather than doing what @Myfriendis410 said, about using a digital pen.

thats what I read in previous forums about buying these grow tent kits with UFO led lights, that the wattage isn’t proper. How would I find the actual wattage draw of the light? If it happens to be around 100 watts instead of 300watts as advertised do you have any LED lights you’d recommend for my grow tent (3x3x6)?

Is this your light? This one claims 300 watts then uses 55 watts. That’s enough to grow in 1 square foot. Not enough by a long shot. @dbrn32 is our lighting expert: let’s wait on him.


I don’t know what your budget can stand, but HLG lights are among the best out there. If you plan on running one plant at a time I would recommend this:


Definitely a little weak for flowering a 3x3. Qb 260 kit is very popular option in 3x3.

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i was told by the company (A Pot for Pot) that sold me the pot mix etc that the pics looked healthy to them, just a bit overwatered. i had no idea overwatering could cause brown spots like the ones in the picture? they said:

"Hi Tom,

Thanks for reaching out! She looks healthy overall but a bit overwatered.

Once you’ve transplanted, use the weight method in your Grow Guide’s Pro Tip to determine when to water. Add water to maintain about 1/3 of what the pot weighed when it was fully soaked when you set it up. This is the method professional growers use. That’s why you see them always picking up their pots when they walk through their grow, so that they develop an intuitive sense of what their pots should weigh, and when they need water.

Through practice, you’ll gain the same intuition about your pot. As your plant grows bigger and goes into flowering, it will drink more water, and you’ll notice your pot drying out and getting lighter faster. Learning your plant and connecting with it in this and many other ways is part of the fun of growing."

the light that i bought is actually from amazon, one of those grow tent kits @dbrn32

UPDATE: Here’s some pictures of the plant this morning. The spots seem to have gotten more yellow-ish, but the plant in general seems healthy. I’ve maintained the temperature around 77-80 degrees but never higher and I’ve changed the light schedule from 24 hours to 18/6. Because I watered it a whole gallon yesterday it seems the humidity in the tent is fairly high, I had to open the main door for a bit because it was hovering around 75% humidity. Now it’s back down to around 60%.

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That looks like an old beat up leaf. If it bugs you; remove it. Old leaves will die off and get removed. But I don’t see any signs of a calcium def.

You need better lights too.

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would the QB 2 LED kit @MidwestGuy recommended be sufficient lighting for my tent?

It will work for 1 plant, but the 260 that @dbrn32 mentioned would be a better solution.


I think I’m going to go with the one you recommended as I only plan on growing one plant at a time. Here’s some pictures of the plant this morning. First time I’ve noticed this slight “drooping”. Could this be a sign that the plant isnt getting sufficient lighting?

I’m having similar problems with couple of my autos too otherwise seem healthy still growing and ones started flower this week

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