Hey everyone, I need help identifying this issue with one of the seedlings. It just started happening last night and progressively gotten worst. Any idea what caused this and also what’s you’d recommend as a fix? Thanks!
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Don’t sweat the bottom leaves. They will be the first to go later. Plant looks OK.
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Not a problem worth worrying about. Lower leaves usually develop problems over time. It’s normal.
The plant looks pretty healthy.
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Welcome to the forum.
Whenever I see these deficiency posts (there are a lot of them), I often wonder what the root cause is. IMO it’s more than just low on X nutrient. We push these plants with high intensity lights, concentrated nutrients, temp and humidity control, air circulation, and maybe even supplemental CO2, so all other parameters need to be balanced.
For example: Your leaves look very sawtooth-like and slightly taco-ed which leads me to believe your light intensity is high producing heat. High light intensity increases photosynthesis. Increased photosynthesis increases demands across the board (water, nutrients, temp, humidity, air recirculation, etc). Increase temp creates a demand for higher humidity. Everything is connected.
Before attempting to diagnose any nutrient deficiency, test the pH of your water, as it can vary widely depending on the source. It should be between 6.0-7.0. Then, check the pH of your soil or other grow medium.
* Soil: 5.8-6.8
* Hydroponics: 5.5-6.5; most hydroponic nutrient brands will indicate an ideal level for their product
If the pH is correct, your plants may have a nutrient deficiency.
Do you add nutrients? (Calcium and Magnesium requirements increase under LED lights.)
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Thanks for the input!!! I suspect it be the water’s PH issue as well (house Tap RO tested at 7.4-7.6) As for the light, I’m running a Mars SP3000 at 40%. I’m going to move it up a couple inches to see if that helps. Being that I was using RO water maybe less trace minerals? The medium is 50% Coco 40% Worm cast 10% Perlite.
The other plants are loving it except this one. Other plants did’nt show signs of stress either so I guess this strain (NY Diesel) is a bit more finicky than the Gold Leaf and LA Confidential.
On the next watering I’ll lower the water PH to 6.5 and see if that helps.
Thanks again and I’ll keep you all posted on what happens. Luckily I have 3 other plants in the tent in case one or some goes south.
Thank you!!
If your RO is low TDS there are very few (if any minerals) in it (aka “low TDS”).
To dechlorinate tap water fill a bucket with what you need and let it sit out a cpl days, add Cal Mag+ then adjust pH to 6.5 +/- .2.
Your municipality could use chloramine vs chlorine as it’s disinfectant. A granular activated carbon (GAC) filtration system is the most effective way to remove chloramines from water.
With coir you’re going to provide all the nutrition the plant needs. Coir is a blank slate just like low TDS RO or distilled water. In coir some recommend feeding every watering.
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I agree, the ppm meter reads 100ppm for the RO water. I’ll try letting it sit out a couple days and add some cal-mag. Should I do a flush first?
I don’t think you’re in ‘flush territory’. Start adding nutrients a little at first to get to a full feeding over a period of time.
BTW, that leaf may never look better. It’ll probably die off which as others said is perfectly normal for older growth to die off as the plant matures
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Isn’t PH of 6.5 too high for coco? Usually coco growers do their PH around 5.8
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How about a compost tea with epsom salt? Will that work?
Good point. I am so used to my setup. I stand corrected. 
Epsom Salt is Magnesium Sulfate which could help provide Mg but you’re not getting the other nutrients required.
Here’s a quick picture on what it looks like now within the past few days.
Good news…
1.) Looks like a deficiency. Used Humboldt Secret A+B plus their Cal/Iron at 50% lowest recommended strength. I’ll bring it to 100% lowest recommendation next feeding. It doesn’t look it it’s spreading anymore or at least slowed it down for now.
2.) If you compare the initial pictures, the growth didn’t really stop so that’s good too. I’m sure it stunted in some way tho.
Bad news… this is also happening to the other plants. I’m just going to have to go do this to other ones as well.
Will see what happened over the next week.
ThanK Again for everybody’s input!
