Iron Deficiency?

I just moved my plants from the veg room to the flower room. They have been receiving feedings with Age Old Grow and 6.8-6.9 PH'd water under T-5 lights. I moved them into the flower room on Thursday and watered them with Age Old Grow, Microblast and super thrive all 1/2 strength with water PH'd to 6.9. The lights are 6 - 1000 watt HPS and shade cloth is under the lights for the transition. I went into the room on Sunday and saw that they were beginning to yellow from the new growth out to the younger leaves at the top only. I checked the PH of the soil with my soil meter and it reads a range of 6.4-6.8. I also tested runoff water and that tested 6.2-6.4. From what I have read the pics attached look like an Iron deficiency or Sulfur Deficiency or possibly cold roots temps? The water that I used for their first watering in flower was probably only 53 degrees and am not sure if this caused root shock? Any advice would be helpful. Thanks!

More information: this is a soil grow in Black Gold and used 3 Milwaukee PH meters for PH testing in water. Plants are about 2 feet high in 5 gallon plastic grow bags. Temps are 81 high, 71 low. Humidity at 50%. Everything going well before placing into flower room and watering on Thursday.

Look's more like sulfur to me. Feed with some Epsom salts.
Those stems are looking pretty red too. What I did for my plants to help them green up.
I gave them a fish and kelp nutrient mix that also had some molasses, NPK 2-2-2.
I also gave them a dose of CalMag+, a dose of a Zinc and Iron liquid mix, Molasses , Epsom salts, and one drop of organic dish soap per gallon of water as a surfactant, or wetting agent to help break the surface tension of the water so the plant can drink easier. They greened up within a few days or so. I raised the temps too. But I was pulling fresh air from outside. So I just unhooked that ducting and unhooked the exhaust ducting for my hood as well that usually would vent into the attic and instead just started venting my hood back into my room for the winter months. The exhaust from the tent itself is on a separate venting than the hood so the tent still filters and cycles into the attic, but pulls air in from my room instead of fresh outside air through a jack in the wall. To cycle the air through the tent, I still exhaust the tent into the attic because I don't want the humidity in the tent building up. In fact when I stopped pulling air from outside and got my room to heat up more by venting the hood into my room, this increased heat brought down the humidity too so another plus. Also giving them a supplement such as Dark Energy or Big Bud might help too. These are both L-Amino supplements. Cannabis is a c3 plant and can only use L-aminos or left handed. left spinning amino acids. The amino acids will have a chelate (ke-late) effect ot nutrients which allows the plant to feed easier. This will help prevent nute lock out.

Really Sulfur, not iron? I just flushed with chelated iron, epsom salts, and micro blast - all on the lighter side with PH'd water of 6.5. They don't seem to be drinking much since this first watering in flower room on Thursday, 11/20. How do plants become deficient from Sulfur?

It think it can either be lack of sulfur in the soil or it can get locked out from something else.
I don't think they need a whole lot of sulfur even.

You might need CalMag+ to help if its lockout. Also Molasses has some Cal and Mag.

I see, thanks for your input. Do you think my flush mixture is good? Should I wait and see what happens in next two days?

If it is lock out the flush was a good idea. Not sure how good your mix for the flush is, but it should have helped. I would keep going with the Epsom salts next feeding if it hasn't responded. Yeah, wait those 2 more days and then more Epsom salts. If it still don't help maybe its not the sulfur. Make note of it that the stems are looking too red. They are lacking something. PH might even be a little high, but you are in soil so this is less of a issue. Maybe you are not feeding enough you said something about 1/2 strength. Red stems can be a sign they need to be fed more N, P, or K. I believe not getting enough of NPK or CalMag could lock out other things. Too much or too little of something can lock other things out. I also think the red stems could mean too cold as well.

Will do. What if I find that the plants are not eating/drinking - i.e.: bags are heavy for days? I have experienced this before and didn't know what to do in this scenario. I turned on dehumid on high and made the room very warm and still bags stayed heavy with previous watering.

I havn't had to deal with that yet myself, but I'm thinking maybe turning up the fans. oscillating fan. I'm fairly certain that this will help to kind of dry the leaves a bit, or rather help make the plants transpire faster, therefore they would need to drink more. That's more I assume this than anything, haven't had to remedy a slow drinking plant yet. They will drink more once they have bud though too so this will be easier to deal with in a couple weeks or so.

Or go with a drop of organic dish soap per each gallon of water to use as a surfactant (wetting agent) to break the water surface tension so the plant can drink easier. There are other products out there that do this such as Wet Betty. When it comes to using soap I hear dawn is best, just make sure it is organic. Wetting agents basically make your water wetter, lol. Something to do with the Hydrogen atoms in the H2O. Also like how oil and water don't mix. But when you do dishes and that dish soap cuts the oils. Pretty sure the organic soap cuts oils or nutrient salts in the soil or something to that effect. If that makes sense. ;D Surfactants help oils and solids bind with liquids, I believe the solids being nute salts in this case, sometimes even soils can be oily too.

Basically this is how plants sweat.So in theory blow air on the leaves and the plants will sweat faster, and then they will drink more. ;D

I hope you get this all dialed in soon. I don't think we really missed anything.
How much Epsom salts did you use? Maybe it wasn't enough.
I also know something about water pressure in a plant similar to blood pressure in humans. But I'm not sure if it is salt that helps retain more water in plants like what it does in the human body. In the human body salt causes water retention usually when the kidneys are not functioning properly, or bad diet. This excess volume of water is what drives blood pressure up. I'm pretty sure there is some benefit to having more water pressure in a plant, and I think it may have been wetting agents that help with this.

Go easy on the Iron and Zinc. I don't think they need much of that either. The liquid Zinc and Iron supplement I used for example, I used it one time. The bottle said to use it once every three months. But that's also for other plants but ought to be about right for cannabis as well. Just a warning so you don't over do it on that and end up locking something else out.

I've even read before something about putting some galvanized nails in the soil to remedy Zinc deficiency. Zinc deficiency can happen if you have planters sitting on a cement floor, it somehow leeches Zinc, maybe iron too I don't recall. Just a tip for you to read about if you care to anyway. Not even sure if yours are on cement or what.

Also think I read something about the soil possibly needing lime, in the same article/guide or post that I was reading about the galvanized nails helping with Zinc or whatever it was. But I already mentioned your PH seemed a little high, in soil this is less of an issue though. Or it might have been that there was Lime in the cement, Sorry, I can't remember but I'd recommend you look into that if you think it is a Zinc or Iron thing, especially if you are on cement.

Thanks TwistItUp for your input. Can anyone else confirm this is a Sulfur deficiency?

When plants were transported to flower room they were taken outside and temps were 45 degrees and sunny. Could this have caused root shock or temperature shock to the plants? I just saw a site with a similar photo that they denote to temp change: http://www.420magazine.com/forums/problems-pests-disease-control/81275-cannabis-plant-pest-problem-solver-pictorial.html

Even the link you provided look what it says about Sulfur. "Unlike a magnesium deficiency where it starts from the leaves tip and around, sulfur starts from the back of the leaves on forward to the middle of the leaves.". Also your plants could stretch more if the day/night temps are way off from each other. Do your plants have excessive stretch? You said they were cold, but for how long were they out there, and what would be the proper way to remedy them having been cold? I think you already corrected the temperature. So I don't think this should be an issue. I don't agree with the first pic, that is a pic of sulfur deficiency.