Apparent Ca- or nute lockout

Thread starter #1
Hi guys

First time grower and poster here.

I'm running two Blue Widow DWCs and am currently around week 7 of flower. About a week ago one of my ladies started showing rusty spots along the edges of the uppermost leaves, which I suspected was a Ca-. I started feeding EHG Micro which contains trace elements which were missing from the Bloom blend i was using, but it seems my TDS and pH remain unchanged even though the water level is dropping. Buds are growing very slowly, not fattening up and the spotting on the leaves is getting worse. I suspect nutrient lockout.

I am currently flushing them with plain pH'd water (pH=5.7) and was thinking after two or three days I'll start them on a mild nute feed again.

I realize they're pretty late into the flowering stage but I was hoping to just let them keep going so they fatten up a bit more.

Any advice on what's going on and what I should do would be appreciated as I'd hate to lose this grow after all this time and effort!

Parameters:
24"x24"x48" grow tent
300W LED infra full spectrum at 12/12
2x5l bubble buckets
pH=5.7
TDS=500PPM
Water temp=17 degrees Celsius
Ambient temp=20 degrees Celsius
Humidity=70%
Currently at week 7 of flower but due to earlier nute burn during veg and other issues I feel that they're a little bit delayed.



 
Looks like a calcium deficiency to me.
How many PPM is your source water? (I'm wondering if it is hard and so has some mineral content.)
Adding a Ca/Mg supplement like GH CALiMAGic should help, I think...
 
Thread starter #5
Looks like a calcium deficiency to me.
How many PPM is your source water? (I'm wondering if it is hard and so has some mineral content.)
Adding a Ca/Mg supplement like GH CALiMAGic should help, I think...
Untouched my source water is 100PPM. Had absolutely no problems until now (mid flower) but I also suspect Ca-. I added EHG Micro which contains Ca, but I think a nutrient lockout prevented it from being taken up by the plant. So I flushed her for 48hrs and then started a 1/2 strength Micro & Bloom blend. Also did a little defol of her fan leaves as they were blocking a lot of the bud sites. Hoping she will come right now.
 
Thread starter #6
Hey Panda, First off I am a total beginner, this being my first season. But the pH seems to be the biggest red flag to me. Looking at this chart it looks like the plants are missing a ton of good stuff. I had a similar problem last month and corrected pH to 6.5 and fed with Advanced Nutrients Cal-Mag to replace the missing nutrients. http://www.growweedeasy.com/sites/g...trient-deficiency/soil-ph-chart-marijuana.jpg
Thanks Andy, I'm growing in hydro tho, not soil. I've ruled out pH as the problem.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017

JD77

New Member
I had some similar spotting about 3 weeks into veg. I added calimagic and it didnt seem to help at all but I was running a low ph like you. I've adjusted my ph to 6.2 and it seems to have done the trick.
 

Rifleman

Member of the Month: Mar 2016 - Plant of the Month: Nov 2015
Remember the KISS principle. How are you checking pH ? When was the last time you calibrated that method ? I can tell you from experience a cheap pH pen can create havoc, appear calibrated yet not be, etc.

Here's a link to one of my blog entries that'll help you diagnose. Notice nutrients are either mobile, or immobile, and the different symptoms of that.
420 Magazine ®

Final point and I'll crawl back in my corner...IF...IF...you choose to use something other than a buffered nutrient in dwc, and are going to check and adjust pH, buy a quality pen like a Blue Lab. One that will give the same reading everytime, within seconds, even when going from one extreme to another. Or you can do like I do and use Advanced Nutrients pH Perfect or Remo Nutrients and ignore pH altogether. ;)
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Or you can do like I do and use Advanced Nutrients pH Perfect or Remo Nutrients and ignore pH altogether. ;)
I appreciate the fact that your choice of nutrients do not require you to "mess with" pH - but it can still be a valuable tool for monitoring and maintaining the health of your plants, IMHO. Especially when coupled with an EC or "PPM" meter.
 
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TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Yes, Scientific, I meant to type PPM in those quotation marks instead of TDS. I will correct it, assuming the window is still open. Thanks.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
I'm just funnin' ya TS. I always call it a PPM meter. I can never remember the real names. ;)
Fun away, bro. I tend to have a great deal of respect for people who seem to know the definition of the scientific method.

The thing about calling it a PPM meter - which you undoubtedly know, lol, so this is for the rest of the audience - is that it isn't, really. EC meters measure electrical conductivity (of the sample/solution). Makes sense, thus the name, huh? But "PPM" meters - I guess they're mainly called TDS (Total Dissolved Solids) meters - also measure electrical conductivity, and then apply a calculation to give the user a number, which he/she then generally assumes to be the actual parts per million of total dissolved solids in the sample.

And that's all fine and dandy if the sample contains ONE type of dissolved solid (and it "matches" the conversion factor of that meter). In other words, if you add an amount of sodium chloride to distilled water, you could use one of these meters (whatever it happens to be called) to determine how many parts per million of NaCl are in solution. But the nutrients we use have more than one kind of salt in them.

It's late and I am, as usual, both distressingly non-high and exhausted - so I probably screwed the pooch on the above explanation. I take comfort in the fact that (if you are still awake) you can correct my mistakes, and will probably do so in order to help others....
 
The thing about calling it a PPM meter - which you undoubtedly know, lol, so this is for the rest of the audience - is that it isn't, really. EC meters measure electrical conductivity (of the sample/solution).
I think an even better name would be just "conductivity meter" because most people grok the notion of a solution's conductivity changing with the amount of dissolved salts, but the electro part sounds kinda off-putting.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
but the electro part sounds kinda off-putting.
Yeah... I managed to digest electromagnetism, but then they threw electroweak interaction at me.
 

Rifleman

Member of the Month: Mar 2016 - Plant of the Month: Nov 2015
I appreciate the fact that your choice of nutrients do not require you to "mess with" pH - but it can still be a valuable tool for monitoring and maintaining the health of your plants, IMHO. Especially when coupled with an EC or "PPM" meter.
I'll agree with that. I even have all the tools and know how to use them. :) I don't make a big deal of it, but pH and EC(ppm) are checked occasionally... especially if I'm growing something I don't already have dialed in. Mostly my gardens run on auto pilot with few hiccups. Deficiencies are a rarity.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Had you stated dark matter, I'd have... asked you to consider a different theory ;) .