Curled Leaves and A Few Brown Spots

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sapient

New Member
I have new plants underway and am in need of help diagnosing what may be the cause of slightly cupped leaves and a few brown spots. Does anyone know what may be causing the issues described and shown in the attached picture? Thank you.

Light: Timber 4VS 400W @18" above
Cycle: 20/4
Vent Fans and 2x Clip-ons
CO2: 1250ppm
Temp: 82F day 72 night
Soil: Roots Organic
 

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CannaCountry

Well-Known Member
That's a lot of CO2 for such small plants. If it were me, I wouldn't worry about CO2 for now. As small as they are, the ambient CO2 in your air is most likely plenty. When they get bigger and get their feet underneath themselves, then I'd crank up the CO2 and push them. See if that helps, considering I doubt your temps are to blame.
 
S

sapient

New Member
CannaCountry said:
That's a lot of CO2 for such small plants. If it were me, I wouldn't worry about CO2 for now. As small as they are, the ambient CO2 in your air is most likely plenty. When they get bigger and get their feet underneath themselves, then I'd crank up the CO2 and push them. See if that helps, considering I doubt your temps are to blame.
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I am new to indoor and suppose I never gave thoughts to CO2 timing, only ppm control. What detrimental effects can a 1250ppm have in a plant’s early life?

simpleleaf said:
When I see drooping leaves (not curled), I suspect soil pH. Can you do a soil pH test?
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After some reading, I thought pH may be to blame. Today will mark the first watering with lowered pH water. After some quick research, I found that a pH of 6 marks the low end of the suitable spectrum. I watered a bit more heavily with pH of 6 water and will get one of those cheap soil pH testers. Fingers crossed...
 
ColoradoHighGrower

ColoradoHighGrower

Well-Known Member
Do Not dose with calmag yet. Keep on a normal watering schedule, and low nute ppm. You can mix your N veg nutes 50/50 with calmag next watering. Let them dry out/droop from thirst a little between, as usual.
 
ColoradoHighGrower

ColoradoHighGrower

Well-Known Member
That looks like a minor ph issue, and possibly low humidity/too much air flow (raised edges). What are your environmental conditions (temp, RH, wind)? Brown spot doesn't look like a deficiency. Maybe a touch of nute burn, or soil-contact damage to that one lower leaf tip.
 
S

sapient

New Member
ColoradoHighGrower said:
Do Not dose with calmag yet. Keep on a normal watering schedule, and low nute ppm. You can mix your N veg nutes 50/50 with calmag next watering. Let them dry out/droop from thirst a little between, as usual.
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Thanks for addressing the timing on this.

TheGreenGreek said:
Also do you have a PPM meter and pH meter to test your run off?
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Will you please elaborate? I have a pH meter. Run off meaning excess water through the pots during watering?

ColoradoHighGrower said:
That looks like a minor ph issue, and possibly low humidity/too much air flow (raised edges). What are your environmental conditions (temp, RH, wind)? Brown spot doesn't look like a deficiency. Maybe a touch of nute burn, or soil-contact damage to that one lower leaf tip.
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This seems quite astute. I have two small clips on fans blowing on them through their lights on cycle.

I splurged a bit and bought a Sensor Push temp/humidity monitor. I can tell you exact historic ranges for both. Humidity stays b/w 43-60% and temp during lights on is approx 80. During lights off, it dips to around 72.

ColoradoHighGrower said:
Also, raise your light to 24" for now
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Is this inspired by concerns over light burn? I have a dimmer on my Timber light, and I am running around 60% (400w).
 
ColoradoHighGrower

ColoradoHighGrower

Well-Known Member
sapient said:
Thanks for addressing the timing on this.



Will you please elaborate? I have a pH meter. Run off meaning excess water through the pots during watering?



This seems quite astute. I have two small clips on fans blowing on them through their lights on cycle.

I splurged a bit and bought a Sensor Push temp/humidity monitor. I can tell you exact historic ranges for both. Humidity stays b/w 43-60% and temp during lights on is approx 80. During lights off, it dips to around 72.



Is this inspired by concerns over light burn? I have a dimmer on my Timber light, and I am running around 60% (400w).
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overall, looks pretty good- what ever you do, don't over think things and do anything drastic. Patience is 90% of growing. :)

PPM meter gives you a measure of salinity or TDS (e.g., nute strength).

Runoff is the water that drains out of the bottom while watering. You should aim for ~20%+ runoff the be sure you're getting a good soak. Collecting & testing runoff ph can sometimes indicate soil ph issues, but that is fiercely debated here on RIU.. From what I've read, soil ph is usually pretty stable and will self-buffer with quality nutes.

Temps and RH sound perfect.

Lights sound possibly a bit low, may stress a young plant before/without any signs of light burn (mostly due to canopy surface temps), but with dimmer, may be okay.

Maybe try decreasing the amount of direct air flow a little? Point fans above or just to the side of the plant.
 
simpleleaf

simpleleaf

Well-Known Member
sapient said:
Today will mark the first watering with lowered pH water. After some quick research, I found that a pH of 6 marks the low end of the suitable spectrum. I watered a bit more heavily with pH of 6 water and will get one of those cheap soil pH testers. Fingers crossed...
Click to expand...
I aim for 6.3 to 6.5 for water or nutrients. My plants leaves droop more at 6.2. I was wondering about soil pH. Distilled water mixed with your potting mix, let set for a few minutes, then drain and measure the water's pH (well that's how I do it). 1:1 to 2:1 water:soil by weight.
 
S

sapient

New Member
simpleleaf said:
I aim for 6.3 to 6.5 for water or nutrients. My plants leaves droop more at 6.2. I was wondering about soil pH. Distilled water mixed with your potting mix, let set for a few minutes, then drain and measure the water's pH (well that's how I do it). 1:1 to 2:1 water:soil by weight.
Click to expand...
When you do this, do you have a target pH per ratio? Does this assume a flat 7 for the water to start?

ColoradoHighGrower said:
overall, looks pretty good- what ever you do, don't over think things and do anything drastic. Patience is 90% of growing. :)

PPM meter gives you a measure of salinity or TDS (e.g., nute strength).

Runoff is the water that drains out of the bottom while watering. You should aim for ~20%+ runoff the be sure you're getting a good soak. Collecting & testing runoff ph can sometimes indicate soil ph issues, but that is fiercely debated here on RIU.. From what I've read, soil ph is usually pretty stable and will self-buffer with quality nutes.

Temps and RH sound perfect.

Lights sound possibly a bit low, may stress a young plant before/without any signs of light burn (mostly due to canopy surface temps), but with dimmer, may be okay.

Maybe try decreasing the amount of direct air flow a little? Point fans above or just to the side of the plant.
Click to expand...
Thank you for the explanation. I adjusted the air flow and made sure the dimmer is running around 50%. I think I will raise the light a bit, as well.

New photo attached (from today - a few days after the original post) I am beginning to suspect a mineral deficiency or possibly light burn. When I first started out, I was still making adjustments to the setup. These first leaves endured some higher temperatures and, likely, too much light. Thoughts?8448E960-FA34-490E-AB34-ED6201272156.jpeg
 
simpleleaf

simpleleaf

Well-Known Member
sapient said:
When you do this, do you have a target pH per ratio? Does this assume a flat 7 for the water to start?
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I gave the water:soil ratio simply as a guide for how much water (so you wouldn't put a gram or two of soil in a gallon of water!). I believe that distilled water is near 7, maybe slightly acidic.

I personally wish the manufacturers reported the pH of their soil/potting mixes, printed on the bag somewhere. Ingredient labels often list some kind of lime, but don't tell the purchaser the final pH. So, the only way the user knows is to test it.

Another matter is the accuracy of digital pen testers. I don't believe they're that great, the lab grade equipment is much better, but low end lab meters start around several hundred dollars.

The advice that, I think it was ColorodoHighGrower gave you, was good. If you're having some success, don't make big changes, try to keep doing what you're doing, make any changes slowly, and be prepared to reverse course if those changes don't have good results.
 
ColoradoHighGrower

ColoradoHighGrower

Well-Known Member
Don't freak out, stay the course, and take good notes along the way! Keep posting here or start a grow journal as you move forward and post a link to it here, 1) because it's fun, and 2) if you do run into issues, there will be plenty of photos/data to help fellow RUI'ers help diagnose and advise. There is some really experienced talent on this forum, so you will learn a lot! :weed:
 
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