InTheShed Grows Inside & Out: Jump In Any Time
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- #35,002
Okay while we continue to wait for pollen 
, here is a Tuesday update on the potassium bicarbonate for powdery mildew tests I've been running for the last few weeks. And let me preface it by saying I have not been using distilled water, so I may re-run this all again once I get a new bottle. 
My first search was to find what the industry standard dilution was (and farmers don't use distilled water when they spray their fields), and I came across a product called Armicarb which is potassium bicarbonate, and it's dilution rate is listed at 2.5 to 5 lbs. per 100 gallons.
Here's the math on that:
2.5lbs/100 gallons = 1lb/40 gallons = 0.025lbs/gallon = 11.34g/3.8L = 0.3% solution. Feel free to check my math!
So I mixed up a .3% and a .6% solution and tested it on some branches of the old Candida mother that I've been intentionally growing PM on. Neither had any effect.
I did additional sprays at .6% and here are the results of that latest test:
So, plenty of PM, not to mention some leaf damage:
Besides the edge curling and burning, the leaves have a dull quality to them that makes the plant look unhealthy. I've decided that potassium bicarbonate (with tap water) is not the answer to my PM issue so I sprayed that plant with neem oil this morning. I may give it another try with 6% in distilled just to confirm, and I'll update you on that if I do.
Thanks for your interest!
Quotes:
, here is a Tuesday update on the potassium bicarbonate for powdery mildew tests I've been running for the last few weeks. And let me preface it by saying I have not been using distilled water, so I may re-run this all again once I get a new bottle. My first search was to find what the industry standard dilution was (and farmers don't use distilled water when they spray their fields), and I came across a product called Armicarb which is potassium bicarbonate, and it's dilution rate is listed at 2.5 to 5 lbs. per 100 gallons.
Here's the math on that:
2.5lbs/100 gallons = 1lb/40 gallons = 0.025lbs/gallon = 11.34g/3.8L = 0.3% solution. Feel free to check my math!
So I mixed up a .3% and a .6% solution and tested it on some branches of the old Candida mother that I've been intentionally growing PM on. Neither had any effect.
I did additional sprays at .6% and here are the results of that latest test:
So, plenty of PM, not to mention some leaf damage:
Besides the edge curling and burning, the leaves have a dull quality to them that makes the plant look unhealthy. I've decided that potassium bicarbonate (with tap water) is not the answer to my PM issue so I sprayed that plant with neem oil this morning. I may give it another try with 6% in distilled just to confirm, and I'll update you on that if I do.
Thanks for your interest!
Quotes:
Thanks Caddie, and nice to see you around!
Good question con. And congrats on post #35,000!
Thanks Absorber, you made it to the top of the page!
MedScientist
Well-Known Member
WooHoo! Would Now be a good time to test the 1 part Whole Milk, 9 parts water solution?Okay while we continue to wait for pollen
My first search was to find what the industry standard dilution was (and farmers don't use distilled water when they spray their fields), and I came across a product called Armicarb which is potassium bicarbonate, and it's dilution rate is listed at 2.5 to 5 lbs. per 100 gallons.
Here's the math on that:
2.5lbs/100 gallons = 1lb/40 gallons = 0.025lbs/gallon = 11.34g/3.8L = 0.3% solution. Feel free to check my math!
So I mixed up a .3% and a .6% solution and tested it on some branches of the old Candida mother that I've been intentionally growing PM on. Neither had any effect.
At that point I looked up to see what @Melville Hobbes was using for his dilution, and his was a 7% solution! Since I was mixing up 500ml batches I decided to go to a 6% (3g) solution (whole numbers) and see how that did.
Here are the results of that latest test:
So, plenty of PM, not to mention some leaf damage:
Besides the edge curling and burning, the leaves have a dull quality to them that makes the plant look unhealthy. I've decided that potassium bicarbonate (with tap water) is not the answer to my PM issue so I sprayed that plant with neem oil this morning. I may give it another try with 6% in distilled just to confirm, and I'll update you on that if I do.
Thanks for your interest!
Quotes:
Thanks Caddie, and nice to see you around!
Good question con. And congrats on post #35,000!
Thanks Absorber, you made it to the top of the page!
KeithLemon
Well-Known Member
Thanks for the update on the PM.Okay while we continue to wait for pollen
My first search was to find what the industry standard dilution was (and farmers don't use distilled water when they spray their fields), and I came across a product called Armicarb which is potassium bicarbonate, and it's dilution rate is listed at 2.5 to 5 lbs. per 100 gallons.
Here's the math on that:
2.5lbs/100 gallons = 1lb/40 gallons = 0.025lbs/gallon = 11.34g/3.8L = 0.3% solution. Feel free to check my math!
So I mixed up a .3% and a .6% solution and tested it on some branches of the old Candida mother that I've been intentionally growing PM on. Neither had any effect.
At that point I looked up to see what @Melville Hobbes was using for his dilution, and his was a 7% solution! Since I was mixing up 500ml batches I decided to go to a 6% (3g) solution (whole numbers) and see how that did.
Here are the results of that latest test:
So, plenty of PM, not to mention some leaf damage:
Besides the edge curling and burning, the leaves have a dull quality to them that makes the plant look unhealthy. I've decided that potassium bicarbonate (with tap water) is not the answer to my PM issue so I sprayed that plant with neem oil this morning. I may give it another try with 6% in distilled just to confirm, and I'll update you on that if I do.
Thanks for your interest!
Quotes:
Thanks Caddie, and nice to see you around!
Good question con. And congrats on post #35,000!
Thanks Absorber, you made it to the top of the page!
- Thread starter
- #35,005
As I recall milk was the first thing I tried about 5 years ago. I didn't have any luck with it (though others seem to).
I do the testing so no one else has to...not a lot of folks will intentionally grow PM on their plants!Thanks for the update on the PM.
KeithLemon
Well-Known Member
You do a lot of testing and I and others appreciate it.
What's your thoughts on Canola oil for PM
Something in common with my avatar.
The commercial product I found that uses potassium bicarbonate is called Green Cure. By weight it's 85% potassium bicarbonate. Their recommended dilution rate is 2 tablespoons per gallon.
I believe I was using a teaspoon per litre? Which would be 4.9ml/litre, or 0.49%.
It did cause some leaf burning last summer when I used it too much.
If I wrote it in grams instead of ml I screwed up.
Just went back and checked.
I used 1/2 a tablespoon per litre, so that's 7.5ml/litre, or 0.75%.
When I told @HashGirl what rate I used I incorrectly converted it to grams, but I did specify that I did it by volume, not weight, and hadn't converted it to metric.
I used 1/2 a tablespoon per litre, so that's 7.5ml/litre, or 0.75%.
When I told @HashGirl what rate I used I incorrectly converted it to grams, but I did specify that I did it by volume, not weight, and hadn't converted it to metric.
- Thread starter
- #35,010
Just trying to help where I can!You do a lot of testing and I and others appreciate it.
In flower I try to avoid oil sprays since they tend to brown the pistils and coat the flowers, which is why I stop neem oil when I see pistils. Canola oil may work well but I already use neem in veg. What ratio of canola to water is recommended? I can give it a try instead of neem if you'd like.
LOL!
I did get it from your HG post.
Maybe I'm reading the math wrong. So if they recommend .5Tbs/L which is 7.4ml/L, and the common conversion is 1ml=1g so that would make it a .74% solution. But it's only 85% potassium bicarbonate, so that would make it a .63% solution?
I guess my mix (3g in 500ml) was a .6% solution rather than a 6% solution [edited above], but either way it didn't work! Given the leaf damage I don't think I'd want to try stronger.
I'd be interested to see the outcome.
Post in thread 'MarsHydro Sponsors Giveaway Appreciation Grow Room 2 RDWC' MarsHydro Sponsors Giveaway Appreciation Grow Room 2 RDWC
- Thread starter
- #35,012
That's a recipe for mites though, yes?
Apparently it does both
- Thread starter
- #35,014
Oh okay, I'll give it a go but still don't think I'd use it on pistils.
Yea me either just veg
You made me curious, so I weighed a tablespoon of pb, and it's 16.9g. Or my scale needs to be calibrated.
Either way, if it didn't work for you I doubt minute adjustments will change anything, including the leaf damage.
I guess your search for a cure continues.
the chunky kind or the smooth kind?
MedScientist
Well-Known Member
In the Spirit of Medicine Science, I was really hoping you would try it!
gr865
Well-Known Member
Interesting, I am fortunate to not have Powdery Mildew pressure here in South Texas. Now I don't grow outside due to the fact I live in South Texas, LOL.Okay while we continue to wait for pollen
My first search was to find what the industry standard dilution was (and farmers don't use distilled water when they spray their fields), and I came across a product called Armicarb which is potassium bicarbonate, and it's dilution rate is listed at 2.5 to 5 lbs. per 100 gallons.
Here's the math on that:
2.5lbs/100 gallons = 1lb/40 gallons = 0.025lbs/gallon = 11.34g/3.8L = 0.3% solution. Feel free to check my math!
So I mixed up a .3% and a .6% solution and tested it on some branches of the old Candida mother that I've been intentionally growing PM on. Neither had any effect.
I did additional sprays at .6% and here are the results of that latest test:
So, plenty of PM, not to mention some leaf damage:
Besides the edge curling and burning, the leaves have a dull quality to them that makes the plant look unhealthy. I've decided that potassium bicarbonate (with tap water) is not the answer to my PM issue so I sprayed that plant with neem oil this morning. I may give it another try with 6% in distilled just to confirm, and I'll update you on that if I do.
Thanks for your interest!
Quotes:
Thanks Caddie, and nice to see you around!
Good question con. And congrats on post #35,000!
Thanks Absorber, you made it to the top of the page!
Now nit saying you can't get PW in an indoor grow, buddy lost his entire grow to PW a few grow ago.
The grow tent has perfect conditions for PW growth, warm light on period, 70 to 85 degrees and cool nights 65 to 75 degrees.
PW does not need moisture present to cause issues.
Anyway, Shed,, love what your doing.
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