Is this magnesium or potassium def.?

frizzelrip

Active Member
Hey guys without putting alot of info out there on my grow at this second can anbody diagnose this def.? .the pic is a fan leaf off of a Ak49 in its 4 week of flower. This yellowing with brown/rust colored spotting is only on the big fan leaves.
 

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budbro18

Well-Known Member
is it the lower fan leaves? Because i think you might have lock out becaues it looks like a combo of a few different ones. Nitrogen def, mag def, and K def and possible P def. Which usually means your medium/rez is too acidic/basic. More than likely acidic.

Try gettin some dolomite lime. If youre running hydro, id try to raise my ph a little.
 

frizzelrip

Active Member
Bud bro. Im in 3 gallon nursery pots running foxf. Ocean f. 4-1 perlite mix. Feeding every 3 days ,nutrients every other feeding .Now i have heard some questionable stuff about ffof but it gets me through veg. And for the most part holds a neutral ph through the grow (so i thought). Soil ph tested 6.6 in fourth week in veg with a soil test meter an kit. I have purchased Dolomite lime and Epson salt today. just dont want to try to treat a deficiency thats not there ya know. Heres a pic of another fan leaf. its started from the bottom to the upper middle part of the plant. Thanks bud bro
 

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budbro18

Well-Known Member
Id give that a shot. The dolomite lime will help ph and calcium. And the epsom salts will help the mag issues and hoefully everything else will fall in place once thats fixed.
 

powerslide

Well-Known Member
Id give that a shot. The dolomite lime will help ph and calcium. And the epsom salts will help the mag issues and hoefully everything else will fall in place once thats fixed.
How much of each per gallon of water? I have the same thing in FFOF
 

Figong

Well-Known Member
Are you using nutes? The FFOF may be a tad hot, looks to me like a potential multiple nutrient blockage.. most likely due to a high PK.. only reason I am hesitating on that is that I don't see any inter-veinal chlorosis (yet)
 

DoseOfReality

Well-Known Member
Why do people always suggest nutrient lockout when it just might be a defeciency as a result of lack of food due to underfeeding?
 

weedemart

Well-Known Member
I doubt it's lock out, your leaves are not curled or deformed. pretty sure its a cal/mg deficiency, I have same symptom on one of my motherplant.
 

budbro18

Well-Known Member
Why do people always suggest nutrient lockout when it just might be a defeciency as a result of lack of food due to underfeeding?
Generally, newer growers go by the bottle directions on nutes which is often way to strong for the plant. This causes salt buildup and lock out usually, especially if you dont ph and are using alot of nutes which lower the ph. So if you dont ph, have slightly acidic tap water, and are using too many nutes lockout is usually the cause of most defs in plants.

Also, people often ph the nute solution too low. Somewhere around 5.5 when it should really be up around 7 since your medium will be/become more acidic over time and that messes with the nute solutions ph.

Most of the time, alot of problems can be avoided by adding some dolomite/hydrated lime to your soil mix before you plant.
 

Bublonichronic

Well-Known Member
Hmmm K def eh? K usually gets locked out of high salinity mediums right? so If that were the problem a flush might help...bUt it looks more like sign of deficiency in N/P (and maybe some micros like ca/mg)...I'm just no seein K as the culprit....maybe a pic of the whole plant might change my mind tho...but what do I know
 

jondamon

Well-Known Member
If its later stage Mg your leaves will go very paper like and almost white.

But that's a severe Mg deficiency.

image.jpg
 

Jack Harer

Well-Known Member
What are you feeding? Your pH is fine (If you are testing the pH of the soil, and not the run-off) Depending on the concentration of the nutes, the every three day schedule could be nute burn. Otherwise I'd say it's a cal/mag issue. Mg def mimics a P def, too much Ca will lock out Mg. It's a delicate balance. If you rule out nute burn, then try Epsom Salts at 1 tsp per gal. The dead tissue will not regenerate, but all new growth from this point should be fine. I had it the first 2 grows. My dumbass used RO and distilled water.
 
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