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Is this a Magnesium problem?

LizardMan

Member
Ive done this to my self!!! I never bring things from outside to inside, but I had a bunch of used "amended" soil outdoors I have brought inside to use, since im cheap and didnt want it to go to waste!!...

So these originally were decent looking clones in 1 gallon pots of straight pro mix bx, watered a few times with a weak EWC tea and rest of the time just straight water. Under a 600watt MH.

I then used the outside soil and upped the pots to 3 gal of outside soil, and placed them under a Spider Farmer 4000 light, and watered them in with straight rain water.

A week later they started to yellow out but growth continued. I then made a weak alfalfa meal and EWC with some epsom salt and molasses and a shot of thrive alive... An other weak had passed and nothing had changed much, waited another week did some straight rain water.

Its been 4 weeks up potted and im thinking its a Magnesium LOCKOUT and not a nitrogen problem... I think the problems in the ph of the soil, due to me using some wood ash (potash) in my flower teas.. And either the PH swing or having to much Potassium is locking something out...

Planted some seedlings in the mix for fun and at 2 weeks old they are growing great... Which is confusing.

I sent a friend a pic and instantly they said CAL-MAG!!! Like its the be all end all bandaid. I should just pay the money and get a soil test on it since i have a fair bit of it...

20201120_174154.jpg

20201120_174121.jpg
 

elanius

Well-known member
Veteran
Hey man, your friend is right. Its not a solution for all problems, but most of the time, when using LEDs and your plants look like this, you just need calmag. Try it
 

f-e

Well-known member
Mentor
Veteran
Does look like Mg and Ca and the N from the calnit would be nice. Typically a must have with led's so the starting point for sure
 

LizardMan

Member
Is it just me or do the LEDs effect the plants different then the older MH/HPS lights?

Im affraid my ph pf the soil is a little out of wack.... Could a test strip for pools work on a soil slurry... My ph pen broke long ago and since going to soil i haven't needed it
 

AgentPothead

Just this guy, ya know?
If I had to wager, I think it's cause the other lights are wider spectrum, LED tend to be focused spectrum.
 

Drewsif

Member
LEDs seem to grow males fine. That's all I've been able to grow under them. Sexing plants is real easy under leds. The stalled out runts are the females. Maybe one day science will figure it out. Definitely won't be flowering under leds until that day.
 

Creeperpark

Well-known member
Mentor
Veteran
If you use rain or RO you need to supplement with cal-mag. for soil-less mixes. For organic mixes use a small amount Dolomite lime in the water, and that will help stabilize the pH.
 

troutman

Seed Whore
Too much potassium can cause calcium and magnesium issues. Wood ash that you used is rich in potassium. ;)

Coir has lots of potassium too. Can you figure now why they use lots of cal/mag with coir? ;)
 
G

Guest

Too much potassium can cause calcium and magnesium issues. Wood ash that you used is rich in potassium. ;)

Coir has lots of potassium too. Can you figure now why they use lots of cal/mag with coir? ;)

BINGO!!

And MANY commercial EWCs have LOTS and LOTS of potassium/K AND magnesium in them. Often times enough to lend to a lock-out or deficiency symptoms for/of Cal and/or P.

I've had several brands tested, including high end $50/cu. ft. EWC, as well as cheapo sleazo mainstream brands that are criticized for having a ton of sand in them (*Yes, -that- one), and it was the first time I found something to compliment about Wiggle Worm... Yep, it's sandy, but that also means the excesses that so many less-than-thoughtful EWC sources allow, are diluted by the questionable quality control standards they apparently run there..

It was another one of many "Everything is Yin & Yang" moments.
 

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