WOS afghan kush auto leaf problem with pix

These plants are world of seeds Afghan kush autos (femd) they are 21 days old today all 3 showed sex at 2 weeks they have been fed
Humbolt oneness every watering they are getting watered every 4th day (phd to 6.2-6.5)
and have received on feeding with cal mag just noticed these leaves turning rust colored this morn it only seem to be on the lower fan leaves
Ive read all the threads about plant problems and cant seem to find any answers
Help please

lower fan leaves- mobile problem. either N P K or MG.. you probably need more P.. whats your PPM and your nute ratio?

I am useing Hombolt nutes Oneness (5 9 4) I am growing in Happy frog siol, I have no clue what my PPM is (Still a newbie)

are you following the directions on your bottle? your K ratio might be too low.... i use 1-2-2 during flowering

How often are you watering? Could possibly be overwater because Oneness is a fairly complete fert but it does lack calcium and sulfur which in the world of cannabis is very important. Sulfur is a building block for the terpenes "Smells" of the plant. As for oneness, the name is deceiving because you do have to use other products with it.

What are your temps/humidity?

Lights on its 83-85 with 40-45 % humitity Lights off it drops to around 70-71,

MoonRaver said:

How often are you watering? Could possibly be overwater because Oneness is a fairly complete fert but it does lack calcium and sulfur which in the world of cannabis is very important. Sulfur is a building block for the terpenes "Smells" of the plant. As for oneness, the name is deceiving because you do have to use other products with it.

Click to expand...

If I use Cal mag that should make up for the calcium missing from oneness ? and wouldnt overwatering make the leaves droopy and not have the rust splotches on the eaves ??

you see how shiny and dark the leaves are? thats a sure sign of to much N...a nitrogen toxicity is going to effect the other 2 " essential" elements for growth first...so locking out P or K is what i believe has happened...dont go pumping P and K to them now...just flush, and cut out the nitrogen for a few feedings...or cut the ammount in half...and continue.

I think your soil it hot. You have salt buildups that is causing your lock out. You need to flush with plain water ph6-6.5 or with a flushing solution like GH florakleen(cheap). If you don't fix the root of the problem, nothing you add will help in the long run.
Good luck and Jah love!

Flushed them yesterday and the problem does not appear to be spreading and the new growth looks good....Cant beleive how fast these afghan kush's grow !