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Help needed. Nitrogen deficiency?

Discussion in 'Sick Plants and Problems' started by Vanderlei, May 8, 2013.

  1. The two plants in my veg cab have started to show yellowing and brown spotting on the lower leaves. I measured the runoff ph at 5.5 today, so I'm guessing I have nutrient lockout?

    I was surprised by the low ph since my tap water comes out at 7.9 and they've only been getting light nutrients. My organic soil has plenty of lime as well so I don't know why it's dropping that low.

    I gave a foliar feed with a light nutrient solution today. Should I start trying to raise the ph tomorrow or wait for the soil to dry out a bit?

    Attached Files:

  2. i thought lime would decrease pH more
  3. Lime has a neutral PH, so it will increase the ph of low ph soil and decrease the ph of high ph soil.

    I'm also curious about the fact that all or nearly all of these leaves were touching the soil. I use a pressurized sprayer to feed and spray it on the soil. Some of it always splashes back on the lower leaves. Could it just be nute burn?

    I don't fully trust todays runnoff PH reading. I tested my tap water then added the proper amount of ph down (I think) and some dechlorinator, but I never retested the ph. With smart pots it's hard to force the water to fully saturate the soil rather than just run out the sides.

    They look much better today after a flush and foliar feeding. I'll keep an eye on them and recheck the ph in a couple of days. If anyone else has some suggestions or insight, I'd love to hear it.
  4. With a PH of 5.5 you'll be missing P, Ca, and Mg.

  5. How exactly do you get an accurate Ph of a plant growing in soil....? you never can...thoroughly flush with Ph corrected air temp water and allow to settle for 7 days, then feed at half strength for another 2-3 weeks until you see an improvement

    Never be afraid to flush do it one time per month regardless, but do come down hard on your water Ph, get a RO machine or other water fix device

    to my blog:

    good luck
  6. I measured my runoff PH at 6.8 today so hopefully I'm back in good shape. I trimmed off all of the yellowed or spotty leaves so I can better keep tabs on their progress.

  7. Try telling that to the plant....!
  8. I feel its best to wait till the plant is ready to let go of its leaves. The method I use goes as fallows: Leaf looks in bad shape to my eyes, I take the leaf and pull up down left right GENTLY and if it pops off, your golden, if not then wait a few days and keep an eye on those leaves for more signs of stress. Leaving the leaves on will show you the full extent of your damage. If you leave it on and the leaves start improving rather then getting worse, then you know what you did was good and to learn from that.

    SnoxBerry ( DC )​
  9. Good point. I took clones from them yesterday so I guess I was just in trimming mode.
  10. I hear ya man. I went on a frenzy with my plant a few weeks back to get her fluff nuggs away so the plant can spend the energy on the rest of the plant. After i was done with her i was scared i killed her. But she ended up taking very well to it and is now looking beautiful. Hope your clones turn out well. What do you use to clone?

    SnoxBerry ( DC )​
  11. Vanderlie,

    I forgot to mention your PH is a TINY bit high. Some elements will not be able to be absorbed by the plant due to the PH of the soil being 6.8. For instance, your water can be the perfect PH, but if the soil ph is not right..... well then you will run into what happened to me:D

    The ph of my soil was crazy ( forgot what it was) and i had all sorts of problems in the very begining. Once i adjusted the soil PH, the plants started to get better. I thought i had a salt build up or too much or too little nutes.... i was going crazy.

    OHH! The important bit hehe, Try and keep the ph in soil around 6.0-6.4 If you can get it in the middle your plants will be able to take up nearly all of what your feeding it. I really need to find the chart that lists when all the different nutes are able to be absorbed by the plant. Ill look for it and post it for you.

    SnoxBerry ( DC )​
  12. Yeah I saw a chart on the back of my PH down, that showed an optimum PH of like 5.5-6 I think. I thought maybe MJ was different.

    I'm really not sure what's going on with these two plants. I saw some more yellowish spots on the leaves today. The plants in my flower cab are using the exact same soil with the same basic setup and nutrients and haven't had any problems. They're still shooting out plenty of new growth so I don't know.

    For cloning, I did pretty much this:
  13. Ok, I think I found my problem.  Fungus gnats.  I saw gnats flying around in there, but I thought they just were a standard freebie with FFOF.  I didn't realize they could actually harm your plants.  I ordered some Mosquito dunks, so I'll apply that tomorrow.

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