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Help with diagnosis please...

Discussion in 'First Time Marijuana Growers' started by GreenFingeredNewbie, Oct 6, 2018.

  1. My first grow.
    1200w hps
    5weeks into 12/12 lighting schedule
    Plain water
    Soil grown organic
    Purple bud from sensi seeds, NL

    Watering these daily with a small amount of water from a spray bottle. Tried a small amount of NPK liquid fertilizer and almost immediately started showing signs of nutrient burn.
    Reduced watering and almost immediately showed signs of dehydration but Increased water caused signs of overwatering and nutrient deprivation.

    Top leaves curling and dark with papery texture.
    Bottom leaves pale greensand falling off - maybe more than usual for this stage of grow but I don’t know due to inexperience.

    I raised the light but it’s still a bit close. Could anyone help please? I don’t know what else to try?
     

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  2. If the colour is correct they look like they are in really hot soil and over-nuted. Very dark green tho lack of burnt leaf edges doesn't seem to indicate nutrient burn and the yellowing lower leaves don't say that either.

    Excess calcium could cause the dark green and block magnesium tho excess Mg also causes dark green foliage.

    Do you not water your plant to soak the pot? If not you should and maybe get about 50% runoff the first good soak to flush it out a bit.

    At 5 weeks 12/12 it's normal to have older fan leaves yellowing.

    You say plain water so I'm assuming tap water. Do you have any idea of it's quality? You should get a water report from your supplier. Usually free and sometimes found on your town/city website. Minerals in tap water build up in the soil over time and cause high pH and other problems so maybe a good flush with a couple of 100% runoffs is in order to flush some of the crud out. Should be enough nutes left in the soil after to see her to the finish tho some Epsom Salts would add some S to help resin production.

    Magnesium.jpg

    Calcium.jpg

    Your cupping leaves at the top do look like overwatering but The way you have been watering doesn't support that. Heat stress causes them to cup the other way or 'taco' as does toxic salts buildup before the leaves go all burnt and crispy.

    I think a decent flush as I mentioned above could help sort things out.

    Good luck and good growing!

    I found a great spot to download FREE POT BOOKS. I downloaded a grow bible first and got lots more. Books look great and complete like the real ones I have here. No web site but just a page of links. Just right click on what you want and then "Save Link As" to download so they don't open first as some are 50+ megs. They got lots. Enjoy.
     
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  3. Thanks for that. Water is rainwater only. Plants seem thirsty but I thought that might be exces evaporation fromheat of lamps. I will try flushing soil with distilled water 50% run off as you suggest. What saturation of Epsom salts would you suggest? These plants seem quite succeptible to over dosing
    hat
     
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  4. What's your humidity like? Low humidity causes the plants to transpire twice as much water that when it's where it should be. It also gets a lot more nutes than it should too and they build up in the leaves then around the middle of flowering it starts burning up the leaves that go all yellow/brown and crispy.

    You can use your regular water to flush. You should soak it good and let it sit for a couple hours at least so salts can dissolve well then start pouring water thru.

    I'd go a Tblsp/gal/4L on the Epsom Salts. Really hard to overdose plants with sulfur and a magnesium boost is good in later flowering too. I'm going to be adding some Flowers of Sulfur to my soilless mix when I repot hopefully tomorrow so they have extra for flowering. It's finely powdered elemental sulfur I brought home from a hazardous waste disposal plant I worked at 25 years ago. Finally found a use for it. :)
     
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  5. #5 GreenFingeredNewbie, Oct 7, 2018
    Last edited: Oct 7, 2018
    Thanks LabRat. I appreciate the advice. I will try the Epsom salts on one plant as a test. I do have about a kilo of fine yellow sulphur but I’m not confident enough to try using that!

    When you say “soak it good and leave it sit a couple of hours”, do you mean leave it in the water all that time?

    Also, I’m in a cold, damp climate (Ireland) with relative humidity of 70% but I built my grow box from 110mm insulation and plywood so the heat of the lamp has the temp at about 20 degrees Celsius during the 12 light hours and takes the edge off the 10-14 degree air outside at night. To keep the temp up there isn’t as much ventilation/air circulation as I’d like. Holes in the base below the plants and in the lid above but no fan. Maybe this is a problem?
     
  6. I mean saturate the pot so it's well soaked. If the plant is sitting in a pan then it wont hurt to leave some runoff in the pan until you're sure the whole pot is wet. Then set it over a drain or pail and keep pouring water thru to wash out the salts.

    If you have holes at the top and bottom then you'll have some natural convection that will be constantly renewing the air in there. Not perfect but will work.

    My first efforts were in conditions about the same as yours but I've been gradually improving things for decades and am still far from perfect. :)
     
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  7. I agree u got some hot as soil. I get that it's hard to buy soil or want to go organic. Really think people should grow in bag soil to learn first. Than later down the road learn to worm bin and make good soil.

    Sent from my SM-G935T using Tapatalk
     
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  8. Well spotted labrat. I thought that was N tox but suppose the tips would be clawed to shit by that point too if it was. Didn't know calmag could do that. Every days a school day eh : )

    Sent from my SM-G850F using Grasscity Forum mobile app
     
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  9. Thanks guys. Sorry for the basic questions but it’s a bit more sensitive than strawberries! I’ll learn. Thanks again for the help.
     
  10. That's what the forums here for mate. There's always someone happy to help. No problem that can't be fixed around here :)

    Sent from my SM-G850F using Grasscity Forum mobile app
     
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  11. But of an update. The flushing out seems to have helped. Some leaves aren’t going to come back to normal but the plant as a whole is less dark green and sick looking. One new question though...
    Whether as a result of the flushing or by coincidence, the pistils on the main cola are rapidly curling and going brown -I’d say about 70-80% - but on my smaller, lower buds and colas they are only 30% or so amber.
    I know what your are going to say, and I did buy a jewelers loop, but I cannot for the life of me make out the detail on the trichomes to figure out clarity or color. I’ve attached two images, one of the main cola and one typical of the lower buds. Should I harvest or wait?
     

    Attached Files:

  12. I can tell the trichs condition with a 10x loupe but have a 30x for a better look. I crop when mostly cloudy and very few amber. That's peak THC. Amber means the THC is breaking down to CBN that makes you sleepy and the trichs age like that after cropping too so I don't wait for amber.

    Still quite a few white hairs on that main cola so I'd chop them in a week or so and let the lower buds ripen and fatten for at least another week before chopping the rest of the plant. That's the way I do it anyway.

    I have a scope now that goes to 1000x for a real good look if I want but it's not that easy to use.

    CrMassTall130618 002.jpg
     
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  13. Thanks man. I’m partially sighted to begin with so even with the eye loop or the big magnifying glass, all I see is white fur! I’ll give it a week more and invest in a digital microscope for next time. Thanks for the advice.
     
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