Mag Deff? Pics and lots of Info Please help!

ARE YOU USING?

SOILESS:

How long has this problem been going on?

A week ish

What STRAIN are you growing?

Purple Kush

What was the establishing chnique? (seed or clone?)

Clone

What is the age of your plants? 11 weeks


How long have they been in the soil mixture they are in now?
7 weeks


How Tall are the plants?
36"

What PHASE (seedling, vegetative or flower) are the plants in?

end of the 4th week Flower

What Technique are you using? (SOG, SCROG etc)

toped

What size pots are you using? (Include how many subjects to pot)
Beds 4' x 8', 10" deep, 40 plants per bed

What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?)

Promix BX, 1 bail to 1 large bag chuncky perlite

What Nutrient's are you using?

GH 3 part + Bid bud and Carbo load.

How much of each nutrient are you using with how much water? *Knowing the brand is very helpful* Differes every week

How often are you feeding?

every other watering, feed once a week, water once a week

If flowering, when did you switch over to using Bloom nutrients?

5 weeks ago

What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect)

Micro, Bloom, Grow, Addatives

What is the TDS/EC/PPM of your nutrients used?

Different each week, 800-1100

What is the pH of the "RUN-OFF"?

No run off, Cant really saturate beds enough to get a run off, this is the down side of the beds

What method of pH test was administered? Using Strips? pH pen?

pH pen

How often are you watering?

Once a week

When was your last feeding and how often are you feeding?

2 days ago, once a week

What size bulb are you using? 1k

What is the distance to the canopy?

12", parabolic reflector, Light is traveleing about 24" - 30"

What is your RH Factor? (Relative Humidity)

50 - 60%

What is the canopy temperature?

83f - 85f

What is the Day/Night Temp? (Include fluctuation range)

73 - 75f Night, 83f-85f Day

What is the current Air Flow? (cfm etc.)

lots

Tell us about your ventilation, intake exhaust and when its running and not running ?

Sealed room

Is the fan blowing directly at plants?

Yes but osolateing

Is the grow substrate constantly wet or moist?

no

Is your water HARD or SOFT?

SOFT

What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water?

Rain water + dehumidifier water

Are you using water from a water softener?

no

Has plant been recently pruned, cloned or pinched?

no

Have any pest chemicals been used? If so what and when?

No

Are plant's infected with pest's?

yes, Thrips


The problem started about 10 days ago, maybe slightly more on the first to be effected plants,

First signs seem to b e slight yellow spots/blotches, Plants that are effected are lighter shade of green, have blotchy yellow/lighter patches on the leaves, older leaves are very yellow and look like N deff and normal as there low in the canopy. Most effected plants are under the lights, this is what leads me to believe its a deficiency not a lock out, many plants not under the light are darker green.

My guess would be that its a N deff or a Mag deff, but i cant decide which, im using rain and dehumidifier water and no cal mag so it could be a mag deff. Also i dont think some of the leaves dont look like N deff especially the less effected ones.

If somone could give me a concrete answer that would be awesome, but any help pointing me in the right direction would be great to, any other info just ask ill post it.

Now on to thye pics

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Row

Looks to me like they ran out of Nitrogen

Mj

Did you add any lime to your ProMix when you mixed it all up? Some people will say you don't have to and that it's already added. For 13 years, I ALWAYS add lime to my promix because peat is acidic and the lime provides calcium and magnesium as well.

All the other info you listed seems dialed in. The lime thing is all i could think of.

Hey guys thx for the reply's

The lime thing is something i have been considering for a while now and never actually tried it.

I think i will give it a try next time round somewhere, at least on a few beds, what do you ph your water and feed to when using the lime, the same as when not?

Im using all chem ferts so use a lower ph 6.0, some people say to use 6.2 - 6.5 but i have had better results with 6.0 ph, (as its soiless) if i were to lime would in not be raising my ph to the 6.5 range? and act like a more soil based system....

Also do you think it is a mag problem, and if so should i just add cal mag this time to get through.

Thanks again,

maryj315 said:

Looks to me like they ran out of Nitrogen

Mj

Click to expand...

I agree.



Only other thing I could think of is your PH is off, so the N is unable to be uptake to the plant.

Thx for the advice all,

im 100% sure the ph isnt off, so much as its been given a ph of 6.0, meter is defiantly calibrated the watering and feedings were phd correctly, but the real question is whether ph 6.0 is the correct ph to go with in promix using chem ferts.

I have been looking at the ph graphs i have and it does suggest, if you go by the hydro/soiless chart not the soil one that mg gets left out at the lower ph, this is another thing that leads me to believe its mg, but then again if no one thinks it looks like mg, i dont know what to think.......

Other factors are that if it were ph being completely wrong id have expected to see the whole room do it at ruffly the same time but i didnt, it started here and there and now many of the largest plants under the lights are deficient, but im surprised if its N as they have had plenty.

Also im using 2 different recipes, one down one side of the room and one down the other, both sides have done it, so this leads me to belive it is Ph, leaving out a nutrient, eg MG.
The reason i say MG and not N, is that on both the soil and soiless charts N would not get locked out at ph 6.0, but mg would on the hydro/soiless one...

Its driving me insane trying to work it out, and i know why you guys have suggested N deff and maybe it really is that simple, if someone could say for sure thats its not a MG deff then atleast itd narrow it down and point more towards the N deff.

Keep the advice coming and im sure it will get sorted if not int ime for this crop but the next at least.

Thx again

Row

If it is an N deff should i do anything about it?, im at the start of week 5 and they will go 8-9 weeks so another 4-5 weeks left....

will adjusting the ph up or down? allow more N to be available

The reason i dont just want to add more N is that iv had trouble with the claw, N over ferting, and if its ph causing the N to be left out adding more will just create a build up, as its in there the plant just cant get it at the moment, if that makes sense......

argg

Row

Remember that magnesium is needed to make the N work so Mg def leads to N def but yeah around week 3-4 I almost always need to spray with epsoms for a few days until they green up again.

N def starts in the veins of the leaf while Mg starts in between the veins. Mistakenly adding a little Mg to the mix wont damage the plants in the way giving too much N will anyway.

Thats very interesting SuperConductor,

Ill add some epsom salts next watering, like you say it cant hurt like the N might, and if it helps ill know for sure.... i just hope its not to late to help this time round....

What you are describing makes sense to me, i see it around week 4 to,

Thanks for the advice

I have to come down on the PH induced lockout side. My Pro-mix BX starts out at a ph of 3.5 if I do not add lime
Promix should be ph'd like hydro, maybe on the upper end of this spectrum i.e. 6.0-6.3

good luck,
Kindman

BTW, what tips me off that this is a ph issue, is the funky gloss the leafs have.

Hey Kindman69

So are you saying that i should add lime next time and feed with a higher PH of 6.3?

I thought the promix was supposed to be balanced to be around ph 7 with lime already added? i can see how the lime would run out though....

Thanks

row

Well, that's the thing, I thought so too, and I trusted it
Once I noticed forst signs of a ph lookout I obviously tested my run off, and not only was the ph between 3.5-4.0, the EC was also off the chart. I was using ro adjusted to 6.3 ph.
I had to flush them with about 2 gallons per 1 gallon on soil just to get the ph into the upper 5's, whereas the EC dropped rather fast.
I went back to my store and he said that sometimes the batches of promix are not consistent and gave me a big bag of hydrated lime free of charge. I thought soil was supposed to be simple lol.
I'm still messing around with the amount to use, but 1.5 teaspoons of lime mixed in with one gallon of soil gets my ph to about 5.8-6.0. I'm going to fine tune it this weekend.
I'm new to soil though, so I probably approach this soil thing back-ass lol!

Kindman

wasup row! bro i have the same problems with my grand daddy purps but the only difference is i'm doing hydro with 5gal buckets dwc. so everything was fine and green until i decided to add another 1k mh to my veg room and like 5 of my babies started to get light green. i checked my ph constantly and kept it at 5.6 consistently and still same problem. of course i thought it was a N deficiency and i did some foliar spraying with dutch master folitech veg and penetrator and nothing seem to change. so the only thing i can think of is when i added that light which is more energy for plants it needed more mg. and since i'm using ro water i'm lacking a lot of mg. iono what to think i'm still kinda new to all this but hopefully someone can help us.

Hey Bron2k

Thanks for letting me know that you tried the N and it didn't seem to work, this does suggest that its Mg and as I to am using 0-10ppm water, it would make sense,

Could you post a pic of yours please dude? so i can get a comparison

Im going to add some epsom next feed which will be a few days, though i would have thought it will take several days to see a change as im in soiless,


Very interesting Kindman, I am deffinatly going to try the lime thing, even though the guy at the hydro store keeps telling me i dont need it.....

How did you test the soil ph? just run off?, im going to try puting a 150ml of soil in a jug with 150ml of 0ppm ph 7 water stir it, let it sit and see what that comes out at, ill try it with the soil from the beds and that of a new bag of promix

Keep it coming people, i know this can get solved and im sure there someone out there with a concrete answer.

Thanks

Row

so this picture was taking about 3 weeks ago while in veg. i'll try to get some updated pictures for you soon. did all your plants started to get the deficiency or just a couple? cuz i had about 7-8 outta of 36 that actually got light in color. but here you can see the one is obviously turning light green. hope this helps and hope we can figure this shit out..

Row said:

Hey Bron2k

Thanks for letting me know that you tried the N and it didn't seem to work, this does suggest that its Mg and as I to am using 0-10ppm water, it would make sense,

Could you post a pic of yours please dude? so i can get a comparison

Im going to add some epsom next feed which will be a few days, though i would have thought it will take several days to see a change as im in soiless,


Very interesting Kindman, I am deffinatly going to try the lime thing, even though the guy at the hydro store keeps telling me i dont need it.....

How did you test the soil ph? just run off?, im going to try puting a 150ml of soil in a jug with 150ml of 0ppm ph 7 water stir it, let it sit and see what that comes out at, ill try it with the soil from the beds and that of a new bag of promix

Keep it coming people, i know this can get solved and im sure there someone out there with a concrete answer.

Thanks

Row

Click to expand...

Good idea with the 150ml...
I'll try that too
I just checked the run-off.

Kindman

Hmm, that does look alot like the problem im having dude,

Mine didnt start to show it untill about week 3 for the first plants, and yes only some got the problem, started in one area then a few more plants, and it is basically all those right under the lights now, so those going for it the most and using the most nutes, this is why im sure its a deff not a lock out.

looking forward to an updated pic

Im not sure how acurate that way is Kindman, i know i read about it being a way of testing the soil ph somewhere, my concern was that the ph 7 water would bring the ph of the soil towards that number, so say you had a ph 5 soil and put it in ph 7 water it would be say the soil was ph 6. However if you are using distiled/ro water is it so hardly buffered that it dosnt really effect the true soil ph?

Row

What strain is that you are growing to Bron2k. Is it PK?

looks like mg to me.

id use some epsom salts pretty quickly here.

Nitrogen def. starts on the bottom most leaves. since the top leaves are looking pretty yellow, if its Nitrogen the bottom leaves would likely hae all fallen off by now. Have they?

I grow in coco and had mag issues around week 4 of flower until i started using 10ml of Sweet(which is mostly epsom salts).