Can't shake manganese deficiency.

[Sativant]

I've been growing very successfully for 6 years. I've grown landrace sativas and lots of different varieties of marijuana. I've had the usual small issues that I resolved, but this time I am defeated. I've tried lower ph, higher ph with no success.
I'm growing OG Kush by Nirvana seeds and I can't get rid of yellowing newer leaves that eventually develop brown spots and die. I use fox farm trio nutrients supplemented as needed with cal mag. Since having problems I've given weaker feeds less frequently. My light was running at 300 watts (Samsung LEDs) but I've turned it down to 200 for now.
I'm using well water, ph'd to 6.5 (plus or minus). In Stonington Blend soil by Coast of Maine soil that worked really well in the past.
Researching my issues it looked like a manganese deficiency caused perhaps by lockout ? Thinking that the ph was too high, locking out manganese I watered at ph 6. I tested the runoff and it came out at ph 7-7.2. So I watered next time at ph 5.8, but the plants look worse !
I've never had this problem before. I feel like I've tried everything.
Does anyone have any ideas ? I was really looking forward to the OG Kush...

 

[Dr.Mantis]

I’m not a liquid nuts expert, but excess Ca can antagonize Mn by precipitate it out, especially in the presence of carbonates and bicarbonates in the water.

I would try backing off on the CalMag, especially if you have decent alkalinity in your tap water.

 

[Dime]

Are you sure you aren't overwatering ?

 

[jackspratt61]

Looks like na damage mostly. They need N. Do you have calcium nitrate or gypsum?

 

[Dr.Mantis]

What’s the EC on your well water? Have you had it tested for it’s mineral content? Sometimes we’ll water can be very high in certain minerals depending on the body it’s drawn from.

 

[exploziv]

Well water can be a bitch. EC 2 and up is possible, mostly Ca. Check it's EC or do a lab test on it.

 

[troutman]

Big swings in pH always causes problems.
Try to go up or down only 0.2 points at a time.

 

[led05]

I've been growing very successfully for 6 years. I've grown landrace sativas and lots of different varieties of marijuana. I've had the usual small issues that I resolved, but this time I am defeated. I've tried lower ph, higher ph with no success.
I'm growing OG Kush by Nirvana seeds and I can't get rid of yellowing newer leaves that eventually develop brown spots and die. I use fox farm trio nutrients supplemented as needed with cal mag. Since having problems I've given weaker feeds less frequently. My light was running at 300 watts (Samsung LEDs) but I've turned it down to 200 for now.
I'm using well water, ph'd to 6.5 (plus or minus). In Stonington Blend soil by Coast of Maine soil that worked really well in the past.
Researching my issues it looked like a manganese deficiency caused perhaps by lockout ? Thinking that the ph was too high, locking out manganese I watered at ph 6. I tested the runoff and it came out at ph 7-7.2. So I watered next time at ph 5.8, but the plants look worse !
I've never had this problem before. I feel like I've tried everything.
Does anyone have any ideas ? I was really looking forward to the OG Kush...

Mg, Ca, K, P, Fe, N deficiency etc showing, can’t tell ya why but Mn is least your worries imo, best guess soaking wet cool feet or PH issues, wild swings -

Not enough radiant too much 400-700nm, cool wet feet if I had to guess, hard from afar, my best guess…

PS: Calmag is worst product ever made, ratios so effed don’t even get me going - - all your bases fighting each other too… once you start chasing your tail hard to stop

GL dude

 

[Dr.Mantis]

Mg, Ca, K, P, Fe, N deficiency etc showing, can’t tell ya why but Mn is least your worries imo, best guess soaking wet cool feet or PH issues, wild swings -

Not enough radiant too much 400-700nm, cool wet feet if I had to guess, hard from afar, my best guess…

GL

PS: Calmag is worst product ever made, ratios so effed don’t even get me going - - all your bases fighting each other

I wanna give you a huge high five for that PS.

 

[led05]

I wanna give you a huge high five for that PS.

TY brother; an especial nasty curse for a pure LED powered grower

 

[Redrum92]

What would you suggest instead of calmag?

 

[Ca++]

It's not a deficiency, it's toxicity.
I'm interested by the comment it could be Na (salt) and wonder if road salt might be involved, as it's that time of year.

 

[Onboard]

I think it might be light poisoning rather than nutrient issuses. At 70 F / 33% RH, your room is likely too cold and too dry, so the plants can't convert all that strong LED light.

It seems to be a common problem in cold and dry winter grows under strong led lights. When it happens,, everything else gets out of whack, and it can't even drink much water either.

Remedies:
- Get the temps up by adding a radiator or other heat source (or switch to the old MH or HPS light).
- Get a humidifyer to increase humidity.
- Raise or dim the lights until the plants start picking up again.
- Go very easy on food and water until they start bouncing back.

 

[Three Berries]

What would you suggest instead of calmag?

I use chlorides. Ca, Mg, K. Mix or use individually.

 

[Greenheart]

I am interested in what you find as the fix. Are you new to LED? I was struggling for a year with going to LED from HID.

I see the temp says 63 degrees. Two things in my LED grow that made a difference. Increased temps and switching to a fixture that had supplemental IR/UV. Things are healthy again. I was chasing all kinds of deficiency symptoms until those changes. I'll be trying the other lights again soon since she is healthy again. In my situation I suspect it was the temps more than the lighting.

 

[led05]

Cool wet feet, dry winter air adding to your transpiration issues, LED all 400-700nm icing on the cake…. Been growing with & building LED decades now…

Peace & GL

 

[Dr.Mantis]

I use chlorides. Ca, Mg, K. Mix or use individually.

Question for you. How well does cannabis handle chloride? I know some plants are more sensitive than others. For instance I’ve grown a fair amount of tobacco, and chloride makes it essentially fireproof lol.

 

[Three Berries]

Question for you. How well does cannabis handle chloride? I know some plants are more sensitive than others. For instance I’ve grown a fair amount of tobacco, and chloride makes it essentially fireproof lol.

I've been using them for the last couple years. No problems with burning the product.

Chlorides do not bind to soil and are easily flushed out. They are actually starting to use them as fertilizer agriculturally.

 

[Chemical Cure]

I'd say use some Revive by Advance Nutrient, if it keeps up.

 

[jackspratt61]

It's not a deficiency, it's toxicity.
I'm interested by the comment it could be Na (salt) and wonder if road salt might be involved, as it's that time of year.

Na comes in from many sources. The op plants appear to be building na. And they need N. There's a calcium/phosphorus imbalance most likely caused by Na blocking K and a general lack of calcium in the first place. Many good suggestions regarding environment. I'd guess about 4g cano and 2g gypsum would help(perhaps up to even double those amounts). Ammonia based N would be even better considering ph issue.