Plant yellowing, Deficiency caused by pH lockout (i think)

[darcey]

How long has this problem been going on? About a week
What STRAIN are you growing? Paradise Seeds Sensi Star and White Berry
What was the establishing technique? (seed or clone?) Seed
What is the age of your plants? First week of 12/12…roughly 8 weeks old
How long have they been in the soil mixture they are in now? Transplanted to larger pots 2 weeks ago….read below for more details
How Tall are the plants? Little over a foot
What PHASE (seedling, vegetative or flower) are the plants in? Flowering – 1st week
What size pots are you using? (Include how many subjects to pot) 10 Litre normal everyday pots
What substrate/medium are you using? What brand of soil mixture are you using?(percentage of perlite, vermiculite...etc?) Mix of standard potting mix and perlite
What Nutrient's are you using? Power Feed, Seasol
How much of each nutrient are you using with how much water? 4ml per Litre of water (as directed)
How often are you feeding? Only feed once as they are just starting flowing
If flowering, when did you switch over to using Bloom nutrients? See above!
What is the pH of the "RUN-OFF"? 6.8
What method of pH test was administered? Using Strips? pH pen? pH pen
How often are you watering? When they feel light and the soil has pulled away from the pot
When was your last feeding and how often are you feeding? 2 days ago (problem existed before this)
What size bulb are you using? 250w HPS
What is the distance to the canopy? 1 foot
What is your RH Factor? (Relative Humidity) 36%
What is the canopy temperature? 21C
What is the Day/Night Temp? (Include fluctuation range) 21c when lights are on, around 19c when lights are off
What is the current Air Flow? (cfm etc.) 255 CFM centrifugal fan
Tell us about your ventilation, intake exhaust and when its running and not running ? Passive intakes and pull exhaust through the cab to a carbon scrubber then vented out
Is the fan blowing directly at plants? no
Is the grow substrate constantly wet or moist? dry/moist
Is your water HARD or SOFT? Soft
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? Bottled spring water
Are you using water from a water softener? No
Has plant been recently pruned, cloned or pinched? No


**Edit** The pot's soil pH is around 6.8-7 and the pH of my water is 6 **Edit**

Hi guys,

I had some major issues about 2 weeks ago when a friend re-potted my plants for me (used composted cow manure in the soil mix which made it very alkaline) The plants were quickly removed once they started showing pH issues and re-potted in standard potting mix with perlite to assist drainage.

Two weeks later they are looking better and I decide to flower…I’m now about 1 week into 12/12 and they plants have started to yellow around the edges of their leaves. I’m guessing this is a pH lockout issue (and looks like Mg to me) but I wanted to double check with you guys before doing anything.

Cheers

 

[koidr]

Yes it is mg give them cal mag in yhe next feeding they will be fine

 

[goneforasmoke]

hi im wondering if any one can help, i seem to have a similar problem (pictures in album) if any one can point me in the right direction and need to know any details ,
Im still in veg and running the same as darcey but my light is a 250w cfl enviro light, medium is terra canna, my ph is 6.3, rh is 60%, temp is 20c, nutes are rizo, canna A & B,
hoping it's not to late and i can save them,

 

[Blue Dot]

What is the pH of the "RUN-OFF"? 6.8

You wouldn't get a Mg def at pH 6.8 but you surely would get a zinc def:

Mag starts near the lower portion of the plant while Zn starts right below the new growth.

http://www.icmag.com/ic/showthread.php?t=11688


EDIT: Just noticed you are using bottle SPRING water.

Not a good idea as many spring waters have high Na (sodium) among other things that are out of balance.

 

[darcey]

Thanks for the info everyone!

koidr - Cheers mate, i will give it a try next water

Blue Dot - Sorry that was a typo! I copied and pasted the list from another thread and missed that one

When using straight water the ph is around 6.0 and 6.1-6.2 when i use powerfeed/seasol combo..

I know the spring water isn't idea but the local water is crap and i don't have the space to sit water for a couple of days while fine tuning the pH...sodium rate for the water i'm using is 3.0mg/L...Is this too high?

 

[Hazy Lady]

That looks as classic a Mag deficit as i ever saw, you could use these pics to demonstrate, Blue dot's pic IS a Zinc deficit though.

 

[Cozy Amnesia]

Looks like Mg yeah, or maybe Zinc, IDK. MJ needs more Mg in veg and early flower, IIRC. Here's a good pic of what Mg deficiency looks like:

(I think the right side show Mg def. in veg, and the left side shows what it looks like in flower, but I'm not sure)