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Yellow edges and brown spots - possible nutrient or pH problem?

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    SOIL Yellow edges and brown spots - possible nutrient or pH problem?

    I have an in-ground outdoor plant in a mix of top soil, peat moss, and sand which I've been fertilizing with a combination of urea, Espoma Tomato-tone, and Espoma Plant-tone in, I think, moderate amounts. I've been watering mostly with collected rain water.

    About a week ago I noticed brown spotting and that the edges of some leaves were turning yellow. Thinking it might be calcium or even pH I flushed the soil with 7-8 gallons of water and added a light mix of nutrients with Dolomite Lime. About 4 days later the symptoms look about the same or possible a little worse. The main areas affected are larger fan leaves, particularly high on the main cola. A lot of the side growth still looks vibrant and green.

    Another plant in very similar soil and feeding conditions is still vibrant and lush, although it is a different strain or is at least expressing a different phenotype, being shorter and bushier than the plant experiencing these issues. That this second plant looks good makes me lean away from pH as the problem, at least.

    The weather for a few weeks has been dry, but somewhat humid. We're expecting a good amount of rain over the next week or so which I'm thinking will do a better job flushing the soil than I did, but I'm still not sure what to do to address this issue.

    Any thoughts or advice would be greatly appreciated.

    Pictures: https://imgur.com/a/gTA0Z
    Last edited by speaknoevil; 08-09-2017, 07:06 PM.

    #2
    Since nobody has replied I thought I'd tack on with a thought I had today.

    As I mentioned, there are two plants. The one yellowing and which has brown spots has also been flowering for, I guess, about two months longer than the other plant. It's even produced some fully mature seeds, to the point where they burst out of their pods. It's had sugar leaves for a few weeks, some pistils are brown, and the oldest buds are starting to swell.

    The other plant, by contrast, only started flowering maybe a month ago and still has mostly green pistils.

    Since the weather is still warm and the days are still long I figured the one that started flowering early would go strong for another month or two, but maybe these are signs that it's getting close to harvest rather than experiencing any sort of nutrient deficiency?

    Both plants are basically bag seed. They were labeled and were from an outdoor grow but I don't recall what they were and they may be from different batches.

    So I guess what I'm asking is, does anyone think the plant in the pictures may be finishing despite weather in the 80s and 14 hour days?

    Comment


      #3
      I'm still very new at this, but the pics look like the same thing I'm dealing with now too. Based on my research, I think it's phosphorous deficiency. Did it start on lower/older leaves and is now "moving up" the plant? That is also a good hint of a mobile nutrient deficiency. Also, phosphorous deficiency seems to hit during flowering and you said it has been in flower stage for a while.

      Like I said, I'm new at this too, but my two indoor grow plants are showing the same problem. I've flushed them every other day for the last couple weeks and am now feeding with a blooming/flowering fertilizer containing phosphorous. Sure hope to see some improvement soon, as they are about a month into flower stage here.

      Good luck!

      Comment


      • speaknoevil
        speaknoevil commented
        Editing a comment
        Cool, thanks for the input. I'm not entirely sure if it started on the bottom, but after reading the page on phosphorous deficiency I think you may be right. I doubt (don't know for sure) that it's directly a nutrient problem, though, because the page says it may be caused by over watering and these plants have been getting a lot of water. There's also a good bit of rain in the forecast, so I'm hesitant to add more fertilizer which I'd have to water into the ground.

        It also says P deficiency may take up to a week to clear up, so I'm thinking I should wait before adding more. Tough call, though. They don't look over watered in terms of being droopy and the soil they're in has good drainage.

        For reference: http://www.growweedeasy.com/phosphor...iency-cannabis

      #4
      I'm not sure if I should keep bumping this or start a new thread... but here goes.

      Today I added Tomato-tone again for the Phosphorous and afterward it occurred to me that I had never tested the pH of my rainwater. So I did that and discovered it's below 6.2. I'm not sure exactly what it is because 6.2 is as low as the test strips I used go. Still, I know phosphorus is best absorbed between 6.2 and 7.0 so I was thinking of spreading some dolomite lime tomorrow to bring that up. The first time I used it I added it to the water, but it doesn't dissolve well so I figure most of that went to waste.

      I'm just a little afraid of trying to do too much and making the issue worse, especially since I watered the fertilizer into the ground today and would need to do the same with the lime tomorrow. As I said though, the soil has good drainage being about 20% sand, 50% top soil, and 30% peat moss. This is also a rather large plant, maybe 7 or 8 feet tall, so I reckon it can use a lot of water despite how wet it's been and will be over the next week.

      As of now, the plant doesn't really look better or worse so I didn't take any more pictures.

      Any thoughts?

      Comment


        #5
        Yeah, It might be best to wait a couple days and look for signs of improvement. I added some phosphorous, calcium, and magnesium fertilizer on my two plants two days ago, and have sprayed the leaves with water and epsom salts (about 1/2 teaspoon in a quart of water). My plants seem to be doing better, but it might just be my wishful thinking. I have noticed no more leaves being affected, yellowing, etc. An no leaves have fallen off either plant for a couple days now too, which I think is a good sign. Fingers crossed for you dude...

        Comment


          #6
          Speaknoevil... Just wondering a few things. You said you've produced seeds from one of the plants. Does that same plant have nugs on it ?? Are you trying to make seeds ?? If not then your other plant has been pollinated and will most likely produce seeds as well. If you can take a pic of the nugs it would help a little as well.

          Comment

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