Is this Magnesium deficiency? (pix)

So I'm growing 3 bag seed strains (all different, i know..). Everything has been great up until now. I'm at Week 4 in veg and here are leaf pix of the 1st and 2nd plant. The 3rd plant doesn't seem to be showing any issues, but is the smallest of the bunch.

Some info on the grow:
- 600w Ushio Opti Blue MH
- Two plants in coco (left and right)
- One DWC (middle)
- Nutrients are Dutch Master Gold line w/ DM Silica
- pH for all plants are always fed at 5.7ph
- Coco plants are at 900ppm (0.7 conversion, so that makes it 650ppm for you 0.5 ppl)
- DWC plant is @ 1200ppm (0.7 conversion)
- DWC res is on a chiller and constant 67F
- Temp w/ lights are 76~79F
- Temp w/ lights off are 70F~73F

Pic 1: Entire grow
Pic 2: Upper middle leaf of plant #2 (middle plant)
Pic 3: Lower middle leaf of plant #2 (same plant)
Pic 4: Lower middle leaf of plant #1 (left plant)

From what I've searched on this forum I'm lead to believe this is a Magnesium issue. Lower leaves do not exhibit this problem and the top of the plant looks great! Just the middle fan leaves seem to be affected. And it's traveling fast... the leaves develop rust spots from the tip and then end up dieing after a few days. Though, the plants are growing faster than the fan leaves are dieing.

Thanks for looking!

this is a link to a different thread on a different site... but the information is invaluable.. bookmark it so you always have it!


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


That being said, yes it looks like a cal/mag deficiency... I usually see those happen together if someone is not on the micro nutrients..

when you correct your problem you should see the spots *stop* producing (they wont go away) and your foliage should all around look a little greener.


I find when my plants are a lime green, not DARK DARK green... they most likely need a little magnesium and that swings everything back into balance.

You could almost confuse mag def. for a SLIGHT nitrogen deficiency if you didn't know better.. but yeah the green picks back up when you correct your deficiency! if not you might want to add some extra nitrogen

good luck

what kind of water r u usin?

@Sr. Verde - Thanks for the link! I'll try adding a bit Cal/Mag from Botanicare I have laying around. Should I go with full strength or half?


@Apollo4 - I'm using a 4 stage RO unit which spits out 10ppm water. Next I add DM Silica till about 150ish-ppm. After that I make sure my pH is under 8.0 to stop any Calcium from precipitating in my rez. Then it's the DM Gold A + B nutes (veg) and lastly I pH down it to about 5.7.

Should my ppm be dropping after each watering? If not does that indicate a nute lockout. My PH is on line for hydro at 5.6 - 6.1. Just calibrated my ph meter as well.

Cal/mag

Are you using any thing for cal/mag?

And what are the infected plants in...dwc or the coco?

Last pic looks more than just cal/mag though