White powdery mildew!

[Gardinhackle]

I went away for a week and left my plants for my wife to care for. Since she can't lift the pots to move them around like I do I decided to leave them in a part of the garden that they could remain night and day. They were up against a fence with foliage all around the plants and it appears as though they now suffer from powdery mildew, a least that's what it looks like.

I pulled most of the leaves that were effected (which were mostly lower....and not many) but should I address this if it appears to continue? I read 35% peroxide mixed with some water works. Is this okay four weeks into flower?

Thanks in advance
Hackle

 

[Skunksta]

mold

 

[Gardinhackle]

Great!

So how do I deal with it?

 

[Skunksta]

I assume its an out door grow. IF its out door hard to manage r/h levels.Wait for someone else to chime in i have
never had any luck other than extreme action someone might know a product that might clear it up.

 

[Gardinhackle]

Thanks @skunksa

I trimmed the really bad leaves off and for the most part it only seemed to effect the lower fan leaves, not any sugar leaves for buds. Now that I'm home I've moved them to full sun and they wont stay in that garden spot any longer, nor will they get rained on any more.

Hopefully someone else will have a suggestion or two for me.

Thanks
Hackle

 

[bobrown14]

That is fer sure PM (powdery mildew).

PM like warm dry conditions to take hold.

When you handle leaves with Pm you can spread the spores to the rest of the grow space and rooms. Wash EVERYTHING that comes into contact with those leaves. You need to cut off the leaves and burn them or toss in the garbage or compost bin.

Treatment is wetable Sulfur. I use Bonide (BND1428) at 2 tbs per gallon and foliar on. Spray entire plant and dont be shy - get the floor and walls a little bit too.

Just say good bye to PM.

Edit: Outdoors the enemies of PM are Sunshine and rain. As mentioned PM like hot DRY conditions. Use the wetable sulfur. It will rinse off next rain. The wet conditions DO NOT promote PM. The lessening of sunlight and dry conditions will promote its growth. Likely there's a source in you yard that some non-canabis plants have a lot of PM.
look around.... its there somewhere. Spray those plants with the sulfur too.

 

[SmokingWings]

PM like warm dry conditions to take hold.

As bobrown mentions the spores for the Powdery Mildew spread and take hold on the plant when it is dry. The spores do not spread when it is raining since they cannot come loose and even if they did the rain would wash them off. The spread starts once the rain ends and the surface dries out and the winds start to blow them off.

A lot of growers think that the problem has just started when they see the mildew on the leaves of their plant. Most likely the problem started 2 or 3 weeks ago, maybe even a month ago. Back then the spots of mildew were so small they were not easily noticeable.

I trimmed the really bad leaves off and for the most part it only seemed to effect the lower fan leaves, not any sugar leaves for buds.

By now the spores are already on the sugar leaves and also hidden in the buds. Start treating now otherwise in 4 weeks the sugar leaves will be white from the mildew and not from trichomes.

Been through this myself and it is easier to fight Fungus Gnats and Spider MItes at the same time.

 

[Gardinhackle]

That is fer sure PM (powdery mildew).

Treatment is wetable Sulfur. I use Bonide (BND1428) at 2 tbs per gallon and foliar on.

Thanks Bobrown14!

Quick question - can I use apple cider vinegar dilute in water like some sites mention or should I be buying the wetable sulfur as you mention?

 

[SmokingWings]

I am not bobrown but my impression after doing a bunch of reading up on Powdery Mildew last summer is that the apple cider vinegar and water mixture is a great way to put an acidic surface on the leaves of the plants. The spores from mildew and most other similar molds will not start growing on the leaf if it has been sprayed with the vinegar solution. My impression is that the vinegar acids will kill most of the mold but nothing seems to do as good of a job as the wetable sulphur mentioned earlier.

Diluted milk also works because of the naturally occuring lactic acid. My preference is to keep using the apple cider vinegar and water mix as a way to slow down and even prevent a new attack of Powdery Mildew after several sprayings with the sulfur spray.

 

[Gardinhackle]

@SmokingWings , thanks for the advice. I guess I'll pick up some sulfur to have on hand. I just looked at the plants after they have dried from being sprayed with cider vinegar and water and they look great! Cant see any visible signs of mold....for now.

I like the idea of just vinegar but will use sulfur if I have too.

Thanks for all your help guys!

 

[bobrown14]

Yeah you can knock in down with vinegar. It will come back tho.

Wetable sulfur is my go to for any molds PM and soft bodied insects.

It works great and the plants love it.

 

[Gardinhackle]

Thanks Bobrown14! I picked some up today. The first sign of it's return I'll spray them.

 

[sneekymofo]

@bobrown14 - would you suggest using the sulfur after the vinegar since it will come back, or is the vinegar and sulfur a similar treatment?

 

[bobrown14]

I'd just use the sulfur. The plants really like it. Spay a little bit on the soil not too much a little bit.

Some folks in the know think that Sulfur is the 4th major plat nutrient since the earth crust is about 10% sulfur.

 

[SmokingWings]

I like the idea of just vinegar but will use sulfur if I have too.

The apple cider vinegar & water mix will knock back the mildew and it helps put an acidic surface on the leaves which helps control the problem by reducing the chance that new spores will latch onto the leaf.

If I spray with the vinegar mix and the mildew starts to show up again in several days or a week then I go for the wetable suphur spray. I am trying out a pre-mixed spray from Safer Brand and it is really inexpensive considering how well it seems to be working. Several sprayings later and once that has done the job I will spray with the vinegar mix approx once a week.

 

[Gardinhackle]

Thanks @SmokingWings

I'll follow that advice! So far I have not had to use the sulfur spray as the vinegar seems to have done the trick....(along with a bit of leaf pulling).

 

[CE2JD2]

Yeah you can knock in down with vinegar. It will come back tho.

Wetable sulfur is my go to for any molds PM and soft bodied insects.

It works great and the plants love it.

Morning,
So how close to harvest can you apply wetable sulphur? I am just seeing the white devil starting to rear its ugly head?