Disinfecting Tools with Bleach

[Dick Shepardson]

Since I just discovered that I have disease problems in my hasta bed, I need some information on disinfecting my tools. I see different ratios on the net in terms of bleach/water (1/4, 1/9, and 1/10). I plan to use 1 part bleach to 9 parts water. Can I just fill a 5 gallon bucket with this mixture and dunk my tools in it as I go from plant to plant? I also worry about how often I need to refresh the mixture in the bucket. Could I use the same mixture for several weeks? Does anyone have experience with this? Thanks for your help.

[Chris_W]

Hello,

The idea that dipping in bleach will get rid of the virus is one of the myths/misconceptions about HVX. You really need to get rid of and neutralize any plant sap that might be on the tools to prevent it from spreading. A quick dip in bleach won't cut it.

Second, bleach will rust tools, so I don't like to use it. Then, it will last no more than a day or two in an open bucket before it evaporates. You really need to make a fresh solution daily.

I prefer to use pure rubbing alcohol on pruners, knives and scissors, and will scrub them with an alcohol soaked paper towel to remove the plant sap. I also buy the 90% rubbing alcohol.

Bleach, ammonia, and even lysol are known to kill some viruses. I was just talking with a nursery friend the other day who found some research showing that unstable viruses can be killed by a 10% solution of these after soaking for about 30 seconds. Tougher viruses take more like 10 minutes soaking in this kind of solution to neutralize them.

Currently I'm using an ammonia solution, probably 10 to 15%, and I've added dish soap to it. I have a scrub brush in the bucket all the time and will pour straight ammonia on the brush periodically. First I rinse off the tools, then scrub them off, then rinse again. If I'm doing a lot of digging and multiple batches I'll just let the tools soak in the bucket and switch them on and off.

We have also switched to digging with spading forks. This minimizes the root contact and minimizes the number of roots that get cut.

So the idea that you can just dip your tools in bleach to kill the virus is a big misconception. We don't know for sure if this does anything, but that's what is being spread around... You really need to eliminate and neutralize any plant sap. Keep the paper towels handy and soak for an extended period of time. With bleach mix a new solution every day. With ammonia it lasts a lot longer. Lysol also lasts a very long time.

I hope that helps.

Good luck!

Chris

[nimblewill]

Chris, one thing I've never seen discussed is how to best sanitize those tools that hang at the end of your arms. I've always felt that a bleach solution was a little extreme for human skin, but ammonia or Lysol might be OK. I've been washing with soapy water and following up with a 90% alcohol rinse. After 5 or 6 washes, though, my hands start to get a little pruney. I can't imagine how gardening gloves could be kept clean. Maybe latex exam gloves would work. I know, I know, I'm paranoid.

Back to steel tools. The other day it was hot and sunny, and it occurred to me that steel left in the sun for 10 minutes would heat up pretty well. Is it known how sun and/or heat affects the virus (assuming the tools had been cleaned first)?

[Chris_W]

With your hands the same concept works - wash them to remove the plant sap. In theory if you don't have any plant material on you then there is no need to be bleaching or disinfecting. I use the same scrub brush in the bucket to clean under my finger nails. When I'm doing a lot of dividing then I wash with soap and water then do an alcohol rinse. The disposable latex gloves might work well if you remember to change them periodically.

Nothing has really been done as far as research goes, but from what we've seen the virus is most likely spread by tools. If you are damaging tissue with your hands that can spread it too of course, but remember, if you don't damage the tissue the virus really can't spread. So your first line of defense it to minimize the handling, breaking, cutting, dividing, or digging of plants.

Who knows if heat will kill the virus. It might, but Dr. Lockhart mentioned that HVX is a very stable virus that may live for a few weeks in ideal conditions. That is also what leads me to warn people that a quick dip most likely is not enough.

Hope that helps a little.

Chris

[wishiwere]

With Bleach solutions, we were taught that in order for the bleach to work (Correct me if I'm wrong, but it's a dessicant I believe), it has to dry on the material you are working with in order to work. For instance, if you were cleaning a tool, you'd have to let the tool dry thoroughly to kill the virus. Bleach works by drying up the fluid inside the virus cell and thus killing.

We were also taught not to 'wipe' off the bleach, as you are just wiping the bleach off the surface where the virus might be and then it won't have the time to dry the cells out, thus leaving behind active virus to grow.

Just a few thought.

You could make your own wet wipes by adding bleach or ammonia to the container of wet wipes. Then pop them out of the top as needed.

[Jim Soper]

I think the issue with the effectiveness of bleach is contact time. Spraying a bleach solution on a tool and wiping off reduces the time the bleach is in contact with the material on the tool. The “don’t wipe” idea is not that you need to let the bleach dry, but to have the bleach stay in contact with the material you wish to disinfect. Think about our water supply or a swimming pool. Chlorine is used to disinfect, but obviously never dries.

The research I’ve seen suggests different contact times for different viruses. None of the studies I’ve seen have gone past a 10 minute contact time.

The knives I use to divide with are kept in a bleach solution and I now use more than one knife to make sure to give extra contact time. I wear latex gloves and change frequently,and when I don’t change them I wash my hands with a bleach and soap mixture that I use to wash the knives before they go in the container to soak. I figure latex gloves clean off a little easier than my skin and I don’t need to worry about the chemical damaging my skin.

Yes, bleach will cause my tools to rust, but new knives will cost less than infected hostas.


Jim