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Brown Spots and Yellowing of the Leaves

Discussion in 'Marijuana Plant Problems' started by purplehaze007, Nov 12, 2007.


    purplehaze007 Active Member

    Hi, this is my first time growing and my plant is in about its 3rd week of veg. and some of the leaves are starting to get brown spots all over them and turn yellowish. I was wondering if anyone knew what the problem is and what I can do to save my plant. Thanks.

    DoobsDay Well-Known Member

    mo info..........

    cjsesh00 Well-Known Member

    I had this happen to me recently, you really have to think about what makes sense here... I started researching plants and nute problems in general, aside from cannabis. My brown spots showed up and I initially thought it was some type of a deposit in the leaves, so I flushed and assumed there were still nutes in the soil. WRONG, once my leaves started to yellow I knew it was a N deficiency, and the brown spots were a P and/or K deficiency. SO i prepared a weak solution and sprayed the leaves the next morning before turning my lights back on. I pruned the damage leaves to rid them of the spots and see if anymore showed up... within 3 days the leaves were green and no more spots appeared. I tend to under fertilize the first few weeks and get a feel for my new strains ability to absorb nutes. they all work so differently it amazes me. Even within the same strain each plant has its own regimen. Hope this helps. Just remember to give them a little shot of nutes every time you water (2-4 days apart). Mainly macro nutrients are the ones that need replenishing more often than you think, but don't overdo IT! be gentle!

    User24 Well-Known Member

    rep for that, good post.

    edit: sorry, necro'd it ><

    WWgrower Well-Known Member

    Great post cj. I am currently having the same prob. at the same time. My question to you is this. My plants are just now over 2 weeks and feel they are a little small (2inches) and while some could handle it others in my hydro could not. Is it possible that this could be Mag. Def. Mine looks that way and Iam going to try Epson salts but can't figure out how much to use in a 5 gallon set. If you want to see my thread is in plant problems asking the question is this Mag. Def?

    foolione Active Member

    i have 2 plants groing under a 12 inch flourescent, and to standard grow light bulbs from home depot one is 120watt and the other is 65watt (at night) ..... at about 8am in the morning i put them outside in direct sunlight everyday and bring them in (under the lights i just explained ) at 6pm all night so that i can have them under 24 hr lighting for maximum growth..... first question is this healthy or am i harming my plant?, i ask because recently i am seeing brown spots on the leaves and a little bit of curling leaves.....2nd question what can the brown spots be from?

    ill appriciate it for some feedback fellas, thanks
    Cali chronic

    Cali chronic Well-Known Member

    I would disagree sir on the nutes ---they usually come in the soil and rarely are needed to be added unless 18 hours of light for 4 weeks. I would NOT hit them with that much nute Perhaps you are but it must be a weak mix like 7 -3-3 or less. Less is better in my opinion those nutes can load up in there and burn you in between a watering and you come back to burnt plants. I would say every other time is a lot as I was just in a hydro store where the owner knows his stuff and after I shared my regime he said heavy feeding becareful and I am a every other time guy.

    Antigen Well-Known Member

    To answer your first question, yes it is bad when you move your plants in and out all the time. Your plants want to have a steady light source and environment that isn't changing all the time. Every time you move them back and forth, it stresses them out as they try to adjust to the new environment. Then once they are just getting used to one you move them into another environment. While this is probably not causing the brown spots and curling leaves, your plants definitely don't like it.

    You should pick either inside or outside and leave them in the same place all the time. If you want maximum growth, definitely go with outside. Even though they won't have 24 hour lighting, they will have THE SUN which is so much better than the lights you are using indoors. The sunlight is also free. :)

    Another bad thing about moving them inside and outside is that you are pretty much guaranteed to get spider mites that way. If you don't already know, spider mites are the most horrible, hard to get rid of bug that you could possibly get on your plants. If you keep the plant outside the mites will usually try to move on to other plants that are not so hard for them to feed on. Cannabis is tough and resiny and they don't like it if they have a choice. That said, if you bring them in the house and they have nothing else to feed on, they will invade and eventually destroy your plant. You can tell if you have spider mites by looking at your big fan leaves. There will be tiny white dots on the top of the leaf that come from where the mite sucked the juices out of that spot. On the undersides of the leaves you may be able to see adult mites, they are just small specks and look kind of like moving pepper. If your plants are heavily infested, you might find webs that the mites have made, which are full of more mite eggs.

    bigbudz420 Member

    my tips are turning yellow only the verytips no where else and i vave givin my plant a shot of sugar water to help is this a bad thing

    potfarmer297 Active Member

    hi, i'm planting in soil (light mix) and my plants the have all gotten brown polka dots on the leaves...
    I use bio bizz products but i'm a month and a half into growing and haven't really gotten a chance to use any ferts yet because of the rain.
    Now I wanna know what my problem is, plants seem to be growing fine....or is it because of the rain???..........

    CybrZr00 Member

    No... just yellow tips means you have a perfect nute balance.... or so I'm told!

    Sorry about digging up the dead!

    CALIxKUSH Member

    yo my plant has brown spots like on the bottom leaves i have them under the lights for 18-8 whats hould i do to the leaves

    YarndiYarns Active Member

    18-8 would make it a 26 hour day, that's weird!
    go with 18-6, or 20-4.
    bird mcbride

    bird mcbride Well-Known Member

    Yellowing leaves usually indicate a problem with the roots not being able to absorb enough moisture to keep the plant green so the plant starts feeding from the fan leaves. Potplants need good drainage in their plant pots and they prefer more frequent waterings than other plants. Soils that hold moisture for extended periods are not good for pot because potplant roots need semi-dry conditions to breath. This is why they grow so well in lava rock and clay gravel because they can have the best of both worlds in this type of growing medium.

    BtMaster30K Well-Known Member

    ffs, I have yellowing leaves and brown spots, with a bit of nute burn to. I googled it and came to this thread.. Would be nice if someone Knowledgable about this could post itt
    Mr John likes this.
    roc Eazy

    roc Eazy Member

    im about a Month in growing now (hydro).. just started using maxi grow on my plants.. they LOVED it.. but now.. some brow spots came.. i also started using cal-mag same time as the maxi .. the temp has been the same since birth75-80.. so idk if thats a problem.. am I using TOO MUCH nuts.. should i tend to it MORE FREQUENTLY now that its growin bigger

    needmorechronic Member

    hey dude your temps arent a problem 75-80 is good

    CHUCKTYLAH Active Member

    who said this?

    djruiner Well-Known Member

    over 21,000 views and only 17 comments...must be a record

    CHUCKTYLAH Active Member

    Are you using tapwater? Tapwater will typically have all the cal you need and adding cal/mag can cause problems.

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