Possible Mg Deficency? Having a hard time IDing (pics)

[stillsmokin]

Basic Info:

Doing a heavily modified ebb-grow system. Using hydroton/rockwool mix (3 hydro : 1 rock ).
Using General Hydro Nova Flora series with Extreme Serene in the res.

These plants are in day 12, mix of white widow and burmese kush.

Possible things that may complicate id'ing

-I had some issues with heat hovering around 90 the first 4 days because I had just trippled the lights and my AC system hadn't come in yet. Temps hover around 80 now, with C02 supplement and the water temp being at 72. So this should be a none issue now for nutrients, but it does explain some of the burning/nute-lock out in the lower leaves.

- I have also kept the PH between 6.3-6.5, but I thought the curling might be due to a PH fluctuation, so today I lowered that down to 5.9, and after looking at the nute availability charts, it looks like I should really be in the 5.5 range because of possible Mg unavailability.

Which is why I guess I suspect the Mg deficiency, the slight leaf curl up, the slight twisting, etc.

I have only 2, possible 3 more days before I flip to 12/12 and flower, so I'll be introducing a 50/50 mix of Flora Nova Grow/Bloom and Liquid Bloom as a supplement in the next res change. So should I even worry about this before the res change?

 

[been]

I see the slight yellowing on a few of them but i don't think that's an mg deficiency. If anything it looks like heat stress, but overall the health seems very good to me. You're about to change the res anyway so don't worry about it.

 

[darksideX]

yea..change the rez..and u will be fine..ur gals seem healthy to me..
btw are u the stillsmokin' bro i kno..however welcome to the farm brah..enjoi ur stay..

 

[stillsmokin]

I was reading the air temp guide on this site, and the heat stress thing might be it still.

Currently I'm running 2x1k and 2x400s. The 400s are about 10-12" from the top of the canopy at the moment, and the 1ks are about 20-22" off the canopy. I have a probe attached (you can see in one of the pictures) at about canopy level, and it's been measuring about the same temp as the ambient room temp. I have good air-flow in the rooms thanks too lots of fans, so I'm hoping the radiant vs ambient room temp thing isn't an issue.

But, should I raise the 1ks a bit if this is a sign of heat stress? The 1ks are air-cooled in Sun Supply's Cool Sun Reflectors ( ).

One thing I've noticed is the plants under the 1ks are definitely a bit curlier, but it's not that much of a change. I guess my worry is that I'll move the lamps too high and not give the babies as much light as they can handle.

Darkside,
Thanks for the warm greetings. Probably not the same guy, this was just some generic name I came up with. I like to remain underground as much as I can with my hobby, I've seen with growers who tell too many people about their trade that the paranoia goes through the roof haha.

By the way, this is my 5th try at this, every time I've radically changed my system. It's been a really accelerated learning, I finally feel like I've gotten to a place where I'm understanding what each process and component of the system does in terms of plant growth and health. All it took as a year of sub-par yields (although I guess an avg of .75lbs for 800ws isn't too bad for a novice).

 

[stillsmokin]

By the way, I have to say thank you to this wonderful site. I've lurked a lot of grower forums and this one is by far the most experienced I've seen. Everything else out there seems like my local supply shop, no real tests or comparisons but always wanting to push some new miracle additive that's going to give you those buku yields.

Also, grow room design is pretty fun. Using a space to it's maximum efficency in terms of money invested vs. yield returned is great. I just wish I had learned that keep it simple stupid applies to this hobby as well. Would have saved me thousands of dollars in equipment lol.

 

[seabass212]

looks healthy to me. the one mistake i notice alot is people getting anxious and lower their lights too low too quick. if it gets worst I would think about lifting the lights a bit. Good luck

 

[bigErn]

The lighter color on the new growth is a sign that you could use just a little bit more Mg. They're still looking good and I don't think you have much to worry about right now, but I'm betting it will become an issue when it comes time to flower. Are you running an RO filter on your water? Sometimes I've had a difficult time with city hard water and Mg deficiency. I believe that it has something to do with either the Mg getting bound up with other ions in the hard water or some sort of osmolytic issue although I'm not completely sure.

 

[bigErn]

I didn't see the other pictures, doh. Yeah, I think you need to add some Mg soon. Cal-Mag boost, or Epsom salts should make them happier. Usually shortly afterwards you can see the green even up a bit more.

The reason for this is that Mg is a vital component of chlorophyll, so if there's not enough Mg, some of the newer growth isn't able to keep up with chlorophyll production for lack of Mg so it isn't as deep green as more established growth.

Nice setup! lookin' good.