Are my plants lacking Mg?

[SiRStonedAlot]

Hello 420 community! Long time visitor, first time poster!

Week end of week 4 flowering here (entering week 5 tomorrow), and running into a bit of intern-veinal yellowing that I'm leaning toward a Mg deficency on, and I'd like some other opinions on the matter.

This is my 3rd run in the current setup and the last 2 runs have been hell with Salt based nutes (AN, botanicaire) and improper watering (no runoff) causing many lockout problems due to salt buildup. I've then swiched over to the organics world because I want to keep it simple, and not kill off the microherd with a bunch of salts @ 1000ppm (1/2 recommended dose lol).

So this run I've mix up a base soil with FFOF, a dash of dolamite lime, 20% chunky perelite, and a tiny pinch of epsom salt. I didn't feed my girls anything but RO'd water all the way throug veg (0ppm) and they THRIVED, they were in 1 gallon pots for 14 days and really took off because I crammed them under a 600MH in a closet pumped full of co2 (and they were VERY ROOTED clones from an aero cloner so they took off quickly). I transplanted them all to 3 OR 5 gallon pots (depending on availablity) in the same FFOF mixup as veg.

After 1st week of Flowering was over, and the girls started to turn I brewed up a nice Jamacian BatGuano tea (2/3 cup), EWC (2/3 cup), 25ml Liquid carma, 4TBSP Humbolt Honey ES, and a pinch of dolamite all brewing in a 5gallon bucket with an airstone (the poop in a paint trainer bag). Let brew for 48hrs, checked ph (6.5), measured PPM for shits and giggles (600ppm)- mixed a glass of 20% RO water 80% tea, came to roughly 500ppm. The entire week following they recieved only RO Water every other day (im in a dry climate, they drink a lot, my pots are light every other day and top layer of soil is dry). I did NOT add any cal/mag to my RO water (possible mistake). After 7days of plain water I fed the girls a bit of Hydrozyme between 2.5 and week 3. I then made a round 2 Tea with Jamaican Guano (1/2 cup), EWC (1/2cup), 20ml Karma, 3TBSP Roots Organic HPK (bloom booster 0-4-5) to get a source of organic potassium, and 3tbsp hombolt honey ES, pinch of D.Lime. Checked Ph, 6.5, ppm 825. Diluted to 625 and fed through with good runoff. They've since recieved another week of plain RO water, with good runoff.

I'm starting to see the interveinal yellowing that makes me believe these bitches have run out of lime in the soil and are lacking because I'm flushing them too hard with 0ppm RO water (being cautious about not overdoing the nutrients this run to keep my plants healthy, focusing on feeding the microherd/soil rather than the plant herself).

Ok so here are a bunch of shots I took. And last night after freaking I stay up till 8am before lights out, to give them a dousing of epsomsalt 2/3rd's Teaspoon in 1qt sprayer in 0ppm RO water - came out to 250ppm @ 6.7ph.

I picked up some General ORganics CaMg+ today, but didnt want to hit the soil with it because I just watered yesterday with good runoff and the pots are still heavy and top is pretty moist, but I figured I'd throw these pics up, get some ideas, and hopefully resolve the problem and update with some good results..

Sorry if this is a lot of info, It has to be a bit better than little or no info.

Oh BTW, I've got 4-600's 1-1000 HPS, and 1 Spectra300 LED on a rail for supplemental.
Temps are 80, RH 40, Co2 average 1000ppm (600-1500 range) I've got an AC, good circulation, no bugs, daily attention.

2 strains (La Confidential, Blue Banana), problems starting to show onset on both breeds, but half of the bunch are showing no signs as of yet.

Help me treat my girls right!

 

[SiRStonedAlot]

 

[OrganicTreees]

things look fine in there man you're plants look very healthy. How far into flower are they? It's normal for the primary fan leaves on the main stems to start to yellow and die off after flowering starts. The bud leaves provide most of the energy to producing buds at this stage, so the plant moves the stored up nutrients in the main fan leaves first as it starts to consume it's energy

 

[SiRStonedAlot]

These pics were taken on day 28 of 12/12

Maybe I'm over-thinking things here, but I've just seen this exact same thing come on before I had lockout on my last round (underwatering and over ferting with salt nutes) so I'm kind of panicing because I don't want these girls to stall out like the last 2 rounds did.

Thanks for the feedback. I'm going to get some more pics when the lights come on, these pictures are a couple days old.

 

[OrganicTreees]

if you're using salt nutes then it's always a good practice to do a monthly flush to get rid of any buildup you had in veg, now is probably a good time for it, you will see good results with a nice heavy flush and then resume your normal feeding program

 

[GrowCannabis2]

Welk actually your fan leaves are beginning to pray and the burnt tips are to small to tell but it does look like some of the larger fans leaves are either yellowing are so many crystals already its whitish already. I would add epsom salt or a cal mg supp especially if any tips are curling up or your seeing any burnt spots if its a cal mg issue and u flush now you will kill bud production, and overall yield with r/o water you do have to add some type of cal mg supp to replace what is gone

 

[420inOregon]

I read in HT mag that curling leaves is a calcium issue. It said to crush up egg shells to a fine powder and sprinkle it around your plants. I tried it and it worked.

 

[GrowCannabis2]

Really thanks for the tip

 

[FrankFoster]

The plant can pull N from those larger fans in this stage. Just let them pull the nutes from the leaves as they go. Those are so healthy that you could starve them out for the remainder of the grow and they would develop buds based on the fans that exist.

Secondly. Use micro-nutes for the N. I always have a GH micro around for this reason and I push some of that onto them at first sign of trouble to watch the fans eat up the nutes.

 

[GrowCannabis2]

Also don't forget deficiencies are normal in later flowering. As plants tend to use a lot more nutrients and water the farther into flowering they go. Just make sure she stays looking good till flush time. She's looking great now either way. Once flush time comes though the deficiency will absolutely show it's self rather quickly, IMO.

 

[Lord Indica]

Dude! She is awesome! leave her alone she will be just fine. Excellent job.

 

[DEAN420]

things look fine in there man you're plants look very healthy. How far into flower are they? It's normal for the primary fan leaves on the main stems to start to yellow and die off after flowering starts. The bud leaves provide most of the energy to producing buds at this stage, so the plant moves the stored up nutrients in the main fan leaves first as it starts to consume it's energy

its not normal for leaves to start yellowing or showing signs of a def at the stage hes in...

To me it looks like the start of a Mg def, so i'd get some epsom salts or cal-mag to correct the issues.