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Thread: severe yellowing and drying of leaves...

  1. #1

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    Default severe yellowing and drying of leaves...

    hi folks,new to the forum and my first grow and have a major prob i'm hoping you could help me with!

    these were grown from seed and put into veg 5 days ago(18/6) since repotting they have started to yellow.they were healthy before veg and still have new growth.
    they are under 2 600w mh bulbs in cool tubes.
    they were potted in a general potting compost from garden centre and have had no nutes.
    temps vary from 20(lights off) to 28(lights on)
    humidity is in between 35 and 50.
    they have plenty of extraction and air movement.
    they have been watered til compost was damp once since repotting.(water is 7 ph)
    one plant (pictured)is the worst but all seem to be showing signs of the same yellowing...
    help!
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    Last edited by pokerface; 19-11-09 at 06:22 PM.

  2. #2

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    Welcome onboard mate, you will find some good advice on here. . First off, I would say that your water ph is slightly high at 7. Ideally you want it around 6.5 - 6.8. Doesn't sound like a big difference but you can lock out some nutes outwith this range. Do you know your soil ph?. Looks like you have a few issues there bud. There are more experienced growers on here that will give you def answer, but I would say zinc def at the top of the plant poss Mg Magnesium at the bottom.

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    Just thought your soil is still quite fresh, so really it should contain all the necessary elements at such an early stage?

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    cheers for the reply mate.yeah,soil is fresh mate and has added john innes. the ph is now at 6.5(lowered it today). i thought it could have been the temp fluctuation as it was worse on the first day(in between 18 and 31)but thats sorted now and the plants are still getting worse. six plants in total and the others are starting to show similar signs albeit not as bad as this one.
    ((how would i take the soil ph?i only have a liquid testing kit... would putting some soil in a jug of my (6.5ph)water and then taking ph work...?))
    Last edited by pokerface; 19-11-09 at 09:30 PM.

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    Ph your water to 6.5 and flush some through your pots. Ph your run off water, should be around 6.5 - 6.8. They look def mate, prob Mg but if its fresh soil I don't understand it bud? Got me puzzled! There could be a little bit of transplant shock, did you disturb the roots much?
    Last edited by trance; 19-11-09 at 09:45 PM.

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    there's no deficiencies happening, certainly not Zinc anyway, too much fresh soil
    if anything its maybe the soil is to acidic
    have you been able to chech the pH of the run off water?
    get a little soil pH test kit from your local garden centre/shop
    what variety is it just out of curiosity?
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    its westlands multi purpose. i've just ph'd a jug full of water with a handfull of compost mixed in and it's at 5.4!! (the plants were in the same soil(different pots)as seedlings though...with no problems until the repot.)

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    ok well get a proper pH soil test kit to verify
    putting some soil in along with water isnt the best method but it has shown that your soil is very acidic
    this high pH is probably the problem and will be causing nute lock-out
    if your going to repot then add some garden lime to the soil this will raise the pH

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    cheers for the help,will probably repot them asap and add lime as i don't think they'll last much longer if left as they are! what much lime/soil ratio?

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    right,got some garden lime today and mixed it into the soil that the plants are in(they are in HUGE pots so no need to repot.). will see if that helps any.
    is the low humidity an issue?its around 35% with the lights on.

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