Zerotol application schedule…

[stewarjm192]

What is your mix/schedule for zerotol use? I was given some by a fellow club member and now have a use.

I discovered that a weak crabapple of mine had some root galls as I repotted it yesterday. Along with that, I have a number of Chojubai that I know can benefit from periodic prophylactic treatment to mitigate nematodes.

I wanted to know the consensus on timing for most folks. Should it be done during repotting, or not? Before or after? Dosage? I know protective gear is a must, but other dos and Donts? Any species to NOT use Zerotol with?

 

[Bonsai Nut]

I have never used it... but wanted you to know I'm not ignoring this thread

 

[TomP]

I have only used it (or heard of it being used as a fungicide). I don't know what effect it would have on nematodes

 

[stewarjm192]

I have never used it... but wanted you to know I'm not ignoring this thread

Well I know I’ve done peroxide drenches for things in late summer. Reason for this post is that I did a repot on a crabapple just the other day and saw some root gall. I cut out as much as I could and went along my repot, I’m just wondering if I should hit it now with a drench, or wait for it to re establish itself in the pot

 

[Deep Sea Diver]

Ordinary peroxide drench would be fine on Crab Gall

Zerotal 2.0 is used by Michael Hagedorn and he writes about it in his blog, using this chemical on’Chojubai root knot nematodes. Not sure which other pests he might use this very hazardous chemical on. I did see him apply it on chojubai roots

Chojubai Notes: Part 3—Why is my Chojubai weak?

Few plants come without a puzzling issue or two. For ‘Chojubai’ Dwarf Flowering Quince, the most serious issues are in the roots. Chojubai are strong plants that will normally extend 6”…

crataegus.com

Before you use Zerotal 2.0 please note it is one of the most hazardous chemicals I’ve seen used in bonsai. Extreme care should be used in using. storing and disposing of this chemical. To further help you, please read the attached Safety Data Sheet

https://biosafesystems.com/wp-content/uploads/2025/05/SDS-6000-ZeroTol-2.0-Rev-1.pdf

Please Bonsai Safe!
DSD sends

 

[bwaynef]

I've had a Zerotol burn before. Surprisingly, I didn't feel it. I just saw it turn white and ran to the sink. I've got THICK leather gloves that I use when I open the container now.

I didn't spray with it enough last year to have a "schedule." The year before I sprayed weekly or bi-weekly.

 

[BrianBay9]

Ordinary peroxide drench would be fine on Crab Gall

Zerotal 2.0 is used by Michael Hagedorn and he writes about it in his blog, using this chemical on’Chojubai root knot nematodes. Not sure which other pests he might use this very hazardous chemical on. I did see him apply it on chojubai roots

Chojubai Notes: Part 3—Why is my Chojubai weak?

Few plants come without a puzzling issue or two. For ‘Chojubai’ Dwarf Flowering Quince, the most serious issues are in the roots. Chojubai are strong plants that will normally extend 6”…

crataegus.com

Before you use Zerotal 2.0 please note it is one of the most hazardous chemicals I’ve seen used in bonsai. Extreme care should be used in using. storing and disposing of this chemical. To further help you, please read the attached Safety Data Sheet

https://biosafesystems.com/wp-content/uploads/2025/05/SDS-6000-ZeroTol-2.0-Rev-1.pdf

Please Bonsai Safe!
DSD sends

It's peroxide and acetic acid, worth some caution but I wouldn't worry about it as much as some concentrated insecticides / miticides. Treat it like muriatic acid (keep it off your skin).

 

[Deep Sea Diver]

Gosh, regretfully must absolutely disagree with a few folks on this issue, The long time Chemical Hygiene Officer part of me has to step up .

Lots of personal experience over many years helping injured folks who decided safely precautions weren’t for them.
If anyone plans on using this hazardous chemical please follow the SDs recommendations and use appropriate PPE. I

It is a combination of concentrated hydrogen peroxide and peroxyacetic acid.. Its main function is to kill microbes by destroying their cell walls… very bad for human cells too.

Zerotol 2.0 affects both helpful and pathogenic microbes equally. Consequentially, regularly scheduled use without a tangible reason is problematic., killing only helpful microbes in the media.

Risking oneself is a personal choice. Providing incorrect advice on safe use of hazardous chemicals to other folks is something else. Let’s all error on the safe side?

Best to all
DSD sends

 

[BrianBay9]

Gosh, regretfully must absolutely disagree with a few folks on this issue, The long time Chemical Hygiene Officer part of me has to step up .

Lots of personal experience over many years helping injured folks who decided safely precautions weren’t for them.
If anyone plans on using this hazardous chemical please follow the SDs recommendations and use appropriate PPE. I

It is a combination of concentrated hydrogen peroxide and peroxyacetic acid.. Its main function is to kill microbes by destroying their cell walls… very bad for human cells too.

Zerotol 2.0 affects both helpful and pathogenic microbes equally. Consequentially, regularly scheduled use without a tangible reason is problematic., killing only helpful microbes in the media.

Risking oneself is a personal choice. Providing incorrect advice on safe use of hazardous chemicals to other folks is something else. Let’s all error on the safe side?

Best to all
DSD sends

I'm not suggesting that proper PPE should not used. I'm just saying that it's not the most hazardous chemical we might come in contact with. I take offense at your suggestion that I'm providing incorrect advice to others. You're not the only chemist on this site.

 

[JEads]

I try to treat all concentrated chemicals with the upmost respect. I think that at minimum you should use full length chemical gloves and work in a well ventilated space or wear a mask rated to protect against the chemical that you are dealing with.

I rely on Zerotol ((or oxidate, a slightly different chemical compound, but same dilution rate)) in a regular rotation in my garden.
For most things I use 1oz/ gallon of water for above ground applicaitons and 1:250 for soil.
Hope this helps.
John

 

[Deep Sea Diver]

I'm not suggesting that proper PPE should not used. I'm just saying that it's not the most hazardous chemical we might come in contact with. I take offense at your suggestion that I'm providing incorrect advice to others. You're not the only chemist on this site.

Sorry, no offense intended Brian, just trying to provide complete information. Went a bit too far in your direction, which was regretful.

Personally was surprised when entering the world of bonsai the variety and concentration of hazardous chemicals that were being stored and used.

Found over the years it’s often hard to get folks to recognize the actual risks of using hazardous chemicals..

Thus I’m especially cautious when providing advice. It’s-a goal to get the word out on proper PPE use, reading SDS and to recognize the potential effects of one time and repeated use of hazardous chemicals on a practitioner, the trees and the local environment.

Cheers
DSD sends

 

[stewarjm192]

Sorry, no offense intended Brian, just trying to provide complete information. Went a bit too far in your direction, which was regretful.

Personally was surprised when entering the world of bonsai the variety and concentration of hazardous chemicals that were being stored and used.

Found over the years it’s often hard to get folks to recognize the actual risks of using hazardous chemicals..

Thus I’m especially cautious when providing advice. It’s-a goal to get the word out on proper PPE use, reading SDS and to recognize the potential effects of one time and repeated use of hazardous chemicals on a practitioner, the trees and the local environment.

Cheers
DSD sends

Your advice was appreciated. Coming from my woodworking background I’m certainly familiar with SDS sheets and PPE usage, but I certainly won’t risk the “I’ll just be REALLLLLLLLLY careful” card with this one

 

[stewarjm192]

I try to treat all concentrated chemicals with the upmost respect. I think that at minimum you should use full length chemical gloves and work in a well ventilated space or wear a mask rated to protect against the chemical that you are dealing with.

I rely on Zerotol ((or oxidate, a slightly different chemical compound, but same dilution rate)) in a regular rotation in my garden.
For most things I use 1oz/ gallon of water for above ground applicaitons and 1:250 for soil.
Hope this helps.
John

This is exactly what I was after Mr Eads! Thanks so much!

Would you suggest watering this in from a watering can, or using a tub to drench and let things sit in the mixture for a bit?

How long after a repot would you wait before soil application?

What are your goals with “above ground” applications?

 

[JEads]

This is exactly what I was after Mr Eads! Thanks so much!

Would you suggest watering this in from a watering can, or using a tub to drench and let things sit in the mixture for a bit?

How long after a repot would you wait before soil application?

What are your goals with “above ground” applications?

For soil drench on newly repotted trees: After repotting, water the tree normally 3-4x in order to flush out any small particles (especially if you use akadama/lava/pumice) and settle the soil.
Then, give it a few hours to a few days in order to drip off any excess water before dunking. For the Zerotol, we mix up a tub that is slightly bigger than the pot and then submerge the pot slowly into the tub. Keep it fully submerged for 10 minutes or so then extract the pot and let it drain. This is an effective against nematodes.

For foliage and twigs, I think of zerotol as a fire extingusher. It is not a preventative or curative, but will kill any bacteria or fungus issues. So if you have an out of contol fireblight issue, or a botrytis outbreak, this is the chemical I grab. It works immediatly and is extreamy effective. I would do 2-3 applications spread out 7-10 days in order to fully knock down what you are dealing with. Spray until it drips. It may not be the best chemcial for the ongoing battle with a disease, but I do not think it can be beat for what it is good at.

Hope that helps
John

 

[InstilledChaos]

Does anyone have experience with Zerotol HC rather than 2.0? That’s the only one I could get in my area, and bought it not realizing the concentrations are different. It has a much lower % peroxide, and higher % paracetic acid. The upside is that the undiluted formula is much less caustic than 2.0, but it makes the extrapolation from Hagedorn’s advice difficult. The labelled uses are not all the same either.

 

[badatusernames]

Gosh, regretfully must absolutely disagree with a few folks on this issue, The long time Chemical Hygiene Officer part of me has to step up .

Lots of personal experience over many years helping injured folks who decided safely precautions weren’t for them.
If anyone plans on using this hazardous chemical please follow the SDs recommendations and use appropriate PPE. I

It is a combination of concentrated hydrogen peroxide and peroxyacetic acid.. Its main function is to kill microbes by destroying their cell walls… very bad for human cells too.

Zerotol 2.0 affects both helpful and pathogenic microbes equally. Consequentially, regularly scheduled use without a tangible reason is problematic., killing only helpful microbes in the media.

Risking oneself is a personal choice. Providing incorrect advice on safe use of hazardous chemicals to other folks is something else. Let’s all error on the safe side?

Best to all
DSD sends

I really appreciate the detail and caution. I worry that sometimes I get a little frivolous but I always take a long shower afterwards and put any clothes in the wash.

I've always felt long sleeves and jeans were fine but I know some folks dress up in Tyvek, is that really the only way? My neighbors would find that awful strange and concerning so maybe I just need to look into gentler solutions

I also didn't know Zerotol was particularly bad. I have only used it once, to soak my chojubai during a repot. I'm not as aware as I should be of where on the scale of danger certain chemicals fall.

 

[Deep Sea Diver]

One doesn’t have to be an expert, but does have to have a solid working knowledge base.

Here is a veryquick general run It will get you started in the right direction.

First guideline is always to read/follow the proper most recent SDS (gives you the very best info) and manufacturs application instructions.

Second thing is Getting and using quality PPE. This depends upon the level of risk….

Some examples: This takes some study and common sense. Ask someone who is experienced if you aren’t certain. Most manufacturers have a hotline to help.

Tychem suits are generally used for spraying wet chemicals. Tychem or Tyvek can be used for application of dry chems.
Decent gloves (various types), Safety goggles (low hazard no wind)and chemical splash goggles (liquid), rubber boots and long sleeve/full trousers for lower risk.
Also a good 3M respirator with the proper cartridges for inhalation hazards… dust, fumes etc

Of course proper application and timing are key.

Last two things proper cool, ventilated storage using secondary containment (most often not done properly hazarding pets and family) and proper disposal.

Hope this helps get you started.
Cheers
DSD sends

 

[Deep Sea Diver]

@InstilledChaos

Should work fine, but may need adjusted drench time. Read most recent SDS for the product thoroughly. Then follow the manufacturers label / instructions for the plants being treated.

Would PM @JEads for his thoughts. (He’s a really nice, but busy guy, so please be patient). If all else falls you can contact Michael H.

Cheers
DSD sends

 

[JEads]

Does anyone have experience with Zerotol HC rather than 2.0? That’s the only one I could get in my area, and bought it not realizing the concentrations are different. It has a much lower % peroxide, and higher % paracetic acid. The upside is that the undiluted formula is much less caustic than 2.0, but it makes the extrapolation from Hagedorn’s advice difficult. The labelled uses are not all the same either.

I have not used the Zerotol HC. It is the 'residential' version of the 2.0.

H202 and P. acid are strong stuff, so I think i would use the same dilution and see what that does.

The Zerotol HC label says "1:150 or 0.85 fl. oz. of ZeroTol HC to one gallon of water." for foliar applications. This is a little lower than I would use for the same application (1:150) for the stronger 2.0, but I think it would still work fine.

Hope that helps.

ps. Michael only uses 2.0

 

[InstilledChaos]

I really appreciate the input @JEads and @Deep Sea Diver. I have been following the suggested dilutions for foliage application and just extrapolating for the soil drench based on the foliar to soil drench ratios from the 2.0, since the HC isn’t labelled for a soil drench really