brown, rusty spots, crispy leaves

[Hans-von-Dampf]

For the past two weeks, the smaller of my two plants developed these brown patches. Both plants get the same food, but this one is significantly smaller (and 10 days or so younger). The leaves look way darker on this one and what's noteworthy: The brown spots only appear on a few branches and not at all on the other plant.

The plant in question younger than its bigger sibling (issues when germinating), it's a bit smaller in size, but also the stems are thinner and it's less bulky overall.


(ignore the camera's date)

So what's going on? Too much of something? Too little? Soil problems? If you can weigh in here, thank you!

-Hans



Here's my setup:

2 plants grown from seed (White Widow Sensi Seeds White Label) in 15l Plagron Grow Mix (soil) each

4th week of flower

overall 235W TNeon / CFL lights in a DR60 (scrog)

feeding with Biobizz whenever the earth feels dry (or they droop) 2ml Grow / 3ml Bloom / 1ml TopMax last week

recently got my PH-meter fixed, feeding at 6.4 now (could have been lower in the past. When I made an un-buffered sample solution, the mix came out between 5.8 and 6.0)

RH usually around 35-50%

Temps on top around 27°C (80.6°F) / roots around 20°C (68°F)

 

[myiqis55]

That's nutrient burn. Too much phosphate. Flush them out with just water next watering. And remember If you're in soil nutrients only every other watering. And try to water before they start to sag.

 

[Hans-von-Dampf]

I now flushed both plants with a very mild nutrient solution (1/4 the dose) @ PH 6.5

Will see what they look like by the end of the week

Thanks for the input. The BioBizz schedule claims "add with every watering", so I did just that. Let's hope the bounce back

Again, thanks!

 

[jedi5891]

Yes plants have nutrient lock out. You need to flush the plant with 3 times the volume of the container with plain water. This will flush out the build up of salts and the cause of the problem. After the plant has dried out feed with quater strength feed and gradually raise the EC/ppm until plant recovers. This will take at leat 2 weeks for plant to recover and resume normal growth. This definitely works as I've done this myself and recovered plants.
Good luck
Namaste

 

[DunHav`nFun]

Those brown rust spots are classic calcium deficiency...if the leaf veins start yellowing as well , that`s magnesium def , then 5 ml per gal botanicare cal/mag will kick em in the ass as long as ph is within parameters for the uptake.....regardless....from those pics....

Classic calcium deficiency....Good luck....and....

Peace....DHF........

 

[Farmer B]

That happin to me twice in one grow. I didn't water all the way through. I thought I was over watering so I slowed down and that happin. I watered through a few times and it stopped. Spots won't go away. Believe it's calcium deficiency

 

[Farmer B]

Can't see pot size but can happin from root bound also.

 

[Hans-von-Dampf]

The pot size should be enough (4 gal each)
that's all I can offer them anyway

they look happier now. the brown spots haven't spread, the smaller plant looks lighter now (had too much N for the past few weeks) and they're in full bloom (crispy white crystals all over the place)

While I trimmed off everything underneath the net (no leaves or growth that doesn't make it to the top), the canopy is a pretty thick mass of leaves & flowers. Tangled, too.

Of course (6th week of flower) there's some wilting & dying off of leaves, and it's kinda hard to pick out the dead leaves there ... in case I miss one or more, I fear mold and/or budrot might become a serious hazard

should I de-leave the canopy (at least from underneath) or would that do more harm than benefit the plants (buds)?