Another Please Help me thread! Yellowing leaves, brown spots. LED grow.

Hi guys, I've been trawling around here for a few weeks and love this forum. It is thriving with good people, not too many trolls, and lots of polite and humble experts.

Anyways, for the last few weeks I've been running an LED grow in which I've grown up a whole bunch of tomatoes, chilli's, and now am moving to my favourite herb! (for my own personal use of course).

First thing's first I'll post the pics.

All the plants are grown in fresh potting mix which contains some slow release nutrient balls.

Ok so let me start by saying that my Tomatos came out really well, LED'd from seedlings they are now outdoors and quite large. The thing with them though, is they are having yellowed, almost white leaves on parts of the plant, while others are pale green.

The reason I bring this up is because the same started happening with my girls. As a response to yellowed leaves, I did what I now believe to be a classic noob mistake, I added more fertilizer.

I know, I know, worst thing I could have done, right? Ok so once I considered it might be nute burn, I flushed them through with lots of water and havn't used any more nutrients. (There should still be some in the potting mix though).

Anyways, my situation is still worsening and I am starting to worry for my gals. I wondered if some of you kind doctors could have a look and assess the problem. Is it perhaps overwatering? Or is having 20 hour days of 180W of LED (660nm + 630nm RED, Orange, and Blue) blasting their chlorophyll.

Is it some kind of deficiency? Is it because of the ph? There is so many variables with similiar results, I am astounded.

As for the PH, I got a cheap little PH/Moisture/Light meter off ebay, and it is indicating the ph to be at about 7. I don't know how much I trust it but at least it gives us a ballpark.

Thanks in advance guys, look forward to hearing from you.
 

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Mother's Finest

Well-Known Member
Your Ph may be a bit too alkaline but the symptoms don't look like high Ph alone. Please provide a timeline for when you flushed, watered, fertilized and planted. Also, what did you feed her and what is the soil mix?
 

Bublonichronic

Well-Known Member
Hi guys, I've been trawling around here for a few weeks and love this forum. It is thriving with good people, not too many trolls, and lots of polite and humble experts.

Anyways, for the last few weeks I've been running an LED grow in which I've grown up a whole bunch of tomatoes, chilli's, and now am moving to my favourite herb! (for my own personal use of course).

First thing's first I'll post the pics.

All the plants are grown in fresh potting mix which contains some slow release nutrient balls.

Ok so let me start by saying that my Tomatos came out really well, LED'd from seedlings they are now outdoors and quite large. The thing with them though, is they are having yellowed, almost white leaves on parts of the plant, while others are pale green.

The reason I bring this up is because the same started happening with my girls. As a response to yellowed leaves, I did what I now believe to be a classic noob mistake, I added more fertilizer.

I know, I know, worst thing I could have done, right? Ok so once I considered it might be nute burn, I flushed them through with lots of water and havn't used any more nutrients. (There should still be some in the potting mix though).

Anyways, my situation is still worsening and I am starting to worry for my gals. I wondered if some of you kind doctors could have a look and assess the problem. Is it perhaps overwatering? Or is having 20 hour days of 180W of LED (660nm + 630nm RED, Orange, and Blue) blasting their chlorophyll.

Is it some kind of deficiency? Is it because of the ph? There is so many variables with similiar results, I am astounded.

As for the PH, I got a cheap little PH/Moisture/Light meter off ebay, and it is indicating the ph to be at about 7. I don't know how much I trust it but at least it gives us a ballpark.

Thanks in advance guys, look forward to hearing from you.
my money on overwatering...
 
Thanks guys, the soil mix is "Scott's" Osmocote potting mix. It doesn't provide a PH summary or anything unfortunately, but it is 'certified' premium potting mix. I think it might be a combination of the above mentioned things.

I have re-potted to larger pots and withheld watering and for the last couple of days the condition has not continued to worsen (as I feared!) and they are starting to look nice and green.

It was silly of me to fertilize considering there was fertalize pellets in the mixture, I think the original cause of the yellowing was over-watering and maybe slight alkaline pH. I will leave them be for a couple more days, and then if I feel game I may try to SLIGHTLY acid their next watering!

Thanks guys for the input!
 

AKRevo47

Well-Known Member
it almost looks like the problem im having with my plants. do you foliar feed and/or is there a really high RH?
 

snocat

Active Member
if the potting soil you used has ferts in it they are time relese and its hard to control the ferts.its best to use a soiless mix so you can control the ferts.pro mix is good you may also find seedling starter,this usually has no ferts in it either.
 

Equinox117

Active Member
i found the answer to yellow leaves with led's :) & its true for 99% of cases... its leaf spot fungus.. which thrives in a variety of places, 1. shaded areas, 2. damp & cool areas.. etc.. anyway the reason for the problem with led's is cuz there's not a heat source from above so water stays in pots for longer, generally stays cooler in the room & bottoms of plants are generally shaded.. each 1 of these individually are perfect for leaf spot fungus to grow but LED grow areas, especially personal, tent or closet grows provide all of these conditions so would be a miracle if you didnt get it.. hope this helps, it defo did with me! This is also why moving the lights up appears to work because its a larger footprint it's creating less shade for the fungus to grow & is also why cal-mag or lime appears to help because calcium increases defenses against fungus. The 2nd link is so helpful!

http://ipm.illinois.edu/diseases/rpds/648.pdf
http://www.crocus.co.uk/pestsanddiseases/_//top12/fungal/
 
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