Let's play Name That Leaf Issue.

[DirtyLarry]

Hey. I got some leaves with this white, almost powdery look. It's not really spotted. What is it?

 

[MIMedGrower]

Looks like bad case of powdery mildew. I have never dealt with it but many here have. Im sure someone will chime in with a remedy.

 

[mysticepipedon]

Looks like fungus to me.

Green Cure works wonders. It's also pretty safe.

 

[Scrogger2190]

Definitely looks like pm. It looks like you're still in veg so just spray it with some kind of anti fungal. I think neem and azamax double as anti fungal/ anti pest

 

[DirtyLarry]

PM is what I was worried about. Yes, still in veg, but I wanted to flip this week to be ready for 420. Lol. I have some neem oil from a box store. Is that stuff really ok to spray on these girls?

 

[GNick55]

can we get some more pictures of the plants..
how bad do you see the wpm?

 

[DirtyLarry]

I thought you'd never ask :)

 

[DirtyLarry]

Its been a little warm and wet inside the cabinet. For some reason I'm getting more humidity this winter with this coco grow than I did with soil grow in the summer. I did a poor job training these and when I added the screen the leaves were kinda shoved onto each other and some moisture got trapped between leaves. I pulled the worst leaves, maybe half a dozen. There is still a faint whiteness to some of the leaves with a few more obvious ones in the mix.

 

[DirtyLarry]

Do you think I should just try to minimize humidity, keep on top of wiping the leaves dry and leave them be? Or should I spray them with something? Should I wait to flip them? Thank you!

 

[PpmOver9000]

Solid airflow underneath the canopy and some light pruning where leaves are overlapping too much is a good start. Lot's of products work to rid PM, my old grow had a sulfur burner that would turn on for a few hours during the night cycle then exhaust it out before the lights turned back on, never saw PM again after that. There's also wettable sulfur that is super cheap and can be used to foliar, both effective and cheap. Can't use it once you begin flowering though so keep that in mind. Also don't use oil based stuff if u are gon go the sulfur route, it's one of the other. The first thing I mentioned is most important imho, with good airflow and canopy management you shouldn't have issues in future runs. Along with humidity spikes at lights off (humidity should stay consistent or be slightly lower at lights off ideally)

What's the temp/rh in there? And if u have a dark cycle for ur veg; what's the temp/rh at night?

 

[PpmOver9000]

Oh i see 74f/41rh in ur picture. That might be ur issue if u have a night cycle. Having it be 41rh in the day and if it jumps all the way up to 60 or 70 when the lights shut off, that would be a great environment for PM to start. 41 sounds very low, plants will still grow but I don't run veg at that low of an RH because the spike at lights off would be too great.

 

[DirtyLarry]

Oh i see 74f/41rh in ur picture. That might be ur issue if u have a night cycle. Having it be 41rh in the day and if it jumps all the way up to 60 or 70 when the lights shut off, that would be a great environment for PM to start. 41 sounds very low, plants will still grow but I don't run veg at that low of an RH because the spike at lights off would be too great.

I think you pretty much nailed the fluctuation in temp/rh. The cabinet is in a garage and the temps have fluctuated a lot lately.

I may need a more powerful dehu. Any rec there? Is sulfer a less controversial product than oil? Thanks.

 

[DankNugz420]

Some folks don't like to defoliate but maybe a light selective trim job would help in your case. Keeps leaves from stacking and limits transpiration

 

[Mr.GreenthumbOG]

Thick stacked growth is what’s causing the PM. Needs to be opened up. More airflow needed.
Mr. G

 

[GNick55]

if you get rid of it, don’t be surprised if you see it with extreme low humidity like below 40 too.
it can survive for a long time all it needs is a small piece of dead plant material to survive and later pop up when conditions are right..

 

[PpmOver9000]

I think you pretty much nailed the fluctuation in temp/rh. The cabinet is in a garage and the temps have fluctuated a lot lately.

I may need a more powerful dehu. Any rec there? Is sulfer a less controversial product than oil? Thanks.

Sulfur is just the go-to for many larger scale grows because they can burn it and treat an entire room on a timer and it's definitely effective. No which way is better, just have to choose something based on your specific grow. I was just pointing out that they shouldn't be used in conjunction, that would pretty much guarantee some fucked up plants lol.

100% for above as well, inactive spores can be around for a long time and once they find a good landing spot theyll start to multiply again. Such as dead leaves and such, cleanliness is key!

 

[PpmOver9000]

Not sure about the dehu considering it's not inside the actual grow space. I don't have much experience in the way of dehumidifying spaces without a dehu directly in the grow room. But it's a common concern so some thread searching will probably find you a good answer.

 

[PpmOver9000]

This may sound counterproductive, but I would first treat the PM issues and then actually try to raise the RH during the day cycle so your dehu doesn't have to work as hard to prevent the sudden spike at night. If your daytime RH is 65~ your dehu only has to go to 60 or so at night rather than starting at 40 and your dehu has to work to try to keep it in the 40s. Also a RH in the 60-70s is just better for growth in veg anyways. Not that VPD is the end all be all but those ranges get you much closer to optimal than anything in the 40s.

Just for reference a typical ambient RH in a normal room in a house is around 40-50 at nighttime so you're essentially asking your dehu to get it down below ambient levels in a small space full of plants and damp soil. I don't know the size dehu you have but I am going to guess more power is not the answer, just improving the environment would be better. My 2 cents, or maybe my 2 paragraphs .

 

[DankNugz420]

My flower runs go 60% to 70% rh but I defoliate heavy. I agree that leaves are solar panels but I also believe big leaves aren't as efficient. Timing is key in my eyes. I defoliate heavy in veg and schwazze in flower. Go hard or go home kinda deal I suppose lol

 

[DankNugz420]

It's always a learning experience