Help diagnose my plant

Hi I have 3 plants grown from seed, growing medium is a mixture of manure and topsoil, lighting I am using a 600w hps with extraction, temperature consistent between 70-80F. Humidity sits at around 45-50 consistently, using ionic fertiliser grow bloom and boost all to the manufacturer guide lines, homemade growbox around 2"x4" ,So I have 3 plants currently 3rd week into flower been smooth sailing up till now, 1 of my 3 plants (the biggest one would you credit) is showing signs of heat stress but ain’t 100% sure on this diagnosis the top leaves coming from the budding colas are very yellow rest of the plant is still green and healthy looking the other factor is around the same area of the yellowing I seem to have some spikey leave and by that I mean the jagged leave parts are curling up so looks a little jagged but not Tesco as the leabw a are still flat any help would be gravely appreciated thanks

Need pictures…welcome to the community. :+1:

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Thanks for the quick response MrPeat and thanks for the welcome hear are some pictures to help along with my previous comment thanks again !

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Hi and welcome!
How tall are your plants (soil to cola tip) and how far is your light above the plants?

Let’s see some Pictures in natural light


Thats not heat stress nor light stress. At least what I can see. The leaves will be a crunchy brown colores leaves. At least that is what mine looked like when it happened to me.

Hi thanks 420craftsman from (soil to cola tip is 16") and from cola tip to the light is now 20" but was previously also 16" moved up a few inches when I noticed first signs of yellowing and dropped back to 50% nutrients. Watt-Sun I’ll post natural light pictures in the morning there currently sleeping but will definitely get them uploaded in the morning … Thanks again MrPeat yeah heat or light stress was my first thought but swayed away from that my self but am still very unsure what’s causing the issue and wether it’s going to be detrimental to the finished plant hopefully someone’s experienced the same problems thanks again

Hi guys these are updated pictures in the best natural light possible sorry there still no the greatest but there the best I can get at the moment hopefully the 're clearer for a diagnosis thanks again all

Hi I’ve been reading around the form and grow journals and can see from what I’ve read use guys are really experienced and have a lot of understanding of problems I was hoping one of use could help or point me in the direction of someone who could of possible thanks


Sure happy to help. Just fill this out describing your issues.

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COPY/PASTE the below list into your forum post.

Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so; Or post
NA (non applicable)

  • What strain, Seed bank, or bag seed
  • Method: Soil w/salt, Organic soil, Hydroponics, Aquaponics, KNF
  • Vessels: Pots, Grow beds, Buckets, Troths
  • PH of Water, Solution, runoff (if Applicable)
  • PPM/TDS or EC of nutrient solution if applicable
  • Indoor or Outdoor
  • Light system
  • Temps; Day, Night
  • Humidity; Day, Night
  • Ventilation system; Yes, No, Size
  • AC, Humidifier, De-humidifier,
  • Co2; Yes, No

Always try to upload a clear picture of any issues you may have to allow the community to assist you.

Add anything else you feel would help us give you a most informed answer should be included. Feel free to elaborate, but short and to the point questions and facts will help us help you in a more efficient manner :slight_smile:


  • What strain, unknown strain
  • Method: Organic soil
  • Vessels: Buckets,
  • PH of Water, between 6.3-6.7
  • PPM/TDS or EC ionic bloom 7ml to 1ltr water
  • Indoor
  • Light system 600w hps
  • Temps; Day 26c , Night 12c
  • Humidity; Day 40% Night 60%
  • Ventilation system; Yes, Size 4inch
  • AC, Humidifier, De-humidifier, no
  • Co2; No
    Hi @Covertgrower thanks for your quick reply to keep things short 1 of my 3 plants is looking a little sick :persevere: my fist thought was heat\light stress but no longer think this, she’s had no issues until now end of week 3 flowering she has a few yellowing leaves at the top of the plant (sugar leaves) but (not brittle or dry) and some discoloration in the middle of a few leaves this is only happening on 3 colas the rest are fine also the jagged edges of the leaves seem to be raised up I’ve cleaned up the picture to hopefully help thanks again

She may just be a little more light sensitive than the others. Can you move it around in your space so that plant is the farthest from the light? How is your light above your tallest colas?

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Yep, my next question… :point_up::point_up:


@dbrn32 @
my first thoughts were light/heat stress at the time I noticed the yellowing the light was at 16inch as soon as I saw this I raised the light to 20inch and backed of to 50% nutes the only thing that put me off it being light stress it’s only 3 colas that are affected with this discoloration the rest don’t show yellowing at all???

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I think what was happening is that photosynthesis was in overdrive do to proximity of light to plants, and plant was having a hard time keeping up. Even 20" pretty close for a 600, but see how they do. I wouldn’t back nutrients off too much right now either. You are sitting at prime part of grow to see a calcium deficiency.

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Thanks again @dbrn32 with your explanation there seems to be light at the end of the tunnel a thought a had ruined my lady’s but seems it was just down to my error hopefully the damage won’t be to detrimental to the harvest, can I just ask what you recommend for distance from cola to bulb? with the 600w hps As there’s a lot of mixed info I’ve read several times and charts claiming you can hang them between 12-24 inches… I’ll work gently with the nutes just now till she recovers from any stress and I’ll be sure to come back and give you guys a n update in a week, thanks so much for all the help :blush:

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People will run large air cooled hoods pretty close. But really depends on the reflector or hood you’re using. Some of them will condense light pretty tightly and others will open up the light for a lot of coverage. Depending on what you have, I would probably just take a look at where you have good coverage and tweak from there. I would expect 18-24" probably good.

Sometimes you can see issues at a height that works plenty good for others too. You want to make sure that you’re gradually increasing light intensity when you intend to push plants hard. And always be open minded about just running into a plant here or there that wants to be a pain in your rear.

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Thanks @dbrn32 I understand now and should have done a lot more research on the specifics light n hight extraction size and how much air/ heat it’s removed ect but nothing wrong with a bit of learning on the way I guess but it seems the information has always been at hand with the ILGM form witch is grate and full of information… I plan to push the light as hard as possible for my self I’m currently just using a basic flexy reflector wasn’t expensive so can imagine it doesn’t produce the grates light reflection, if that’s what you recommend your self I’ll hang around at 20" and see how they go. thanks again.

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Good morning, it’s update time well was dew to be on Saturday but unfortunately I had to be admitted into hospital for a few days so I’ll do it now @dbrn32 you were spot on my friend my issues were down to heat/light stress that’s now been rectified and the lady’s are loving live fattening up really well and producing some nice frosty nuggs @Covertgrower @MrPeat @420craftsman thanks for all your help guys

Sorry the pictures are the best still in a bit of paint will spend more time next week taking clearer pictures


We do what we can!