Knowledgebase

Plant damage from deck bleach #843189

Asked July 29, 2023, 12:58 PM EDT

A company cleaned our 25 foot deck without protecting the plants in a 3 x 25 foot flower bed with perennials and annuals. It appears they used bleach because I can smell it and the wood is now very light in color. Many plants were damaged but the survivors are covered in a white milky substance that does not wash off. Will the bleach kill all these plants and will it affect the soil in this flower bed?

Ramsey County Minnesota

Expert Response

Good question! It’s hard to say how where the shrubs and plants are affected. 

The first thing I would do is call the company and ask them what they used and the concentration. You’ve probably already done this but if not - do it and explain the damage they caused. 

Bleach is not good for the environment but it will eventually break down in the soil. In fact, we use bleach to clean gardening tools and pots. Just be sure to really dilute it before pouring it out. 

Keep in mind that only the green parts of a plant can photosynthesize. Once new green leaves emerge the plants should become healthy again. 

You may try gently washing some of the leaves with a very weak soap solution to see if that will help remove the residue. But use a very weak solution.

Then, keep them well watered in this heat and they should recover.

Deb Reierson Replied July 30, 2023, 7:17 PM EDT

Thank you very much. I  will contact the company  and ask about the product used and the concentration. I will try a very weak solution of soapy water to see if I can wash off the residue.

Is there any value in having the soil tested? I don't want to rel;ace the plants (next spring) if the soil is contaminated in a way that would impede growth of new plants.

The Question Asker Replied July 31, 2023, 11:49 AM EDT

I don’t really see a value in soil testing because you don’t know what to ask them to test for. If the plants were happy there prior to the deck washing, they should recover.

If you have food growing there, that is another issue and you should remove and put the plants in the garbage. Don’t eat them.  Don’t compost them. 

Deb Reierson Replied July 31, 2023, 12:46 PM EDT
The deck was cleaned with sodium hydroxide and bleach. The company has not provided the concentration. I used a dilute mixture of Simply Green to wash the leaves. I only chose to randomly wash a few here and there due to the number of leaves in 30 plant was unmanageable. The leaves I cleaned had brown spots where the chemicals had been on them. Some leaves fell apart when I gently washed them. In general many leaves are turning brown and curling up. The buds on the sedum autumn joy are turning brown and curling up. The buds on the liatris spicata are turning brown.

This experiences is very painful given that the garden is peaking and many anticipated blooms are apparently dying. Plus the perennials were really thriving before the deck cleaning.

The only edible plant was dill. We ate a small amount the day after the deck cleaning. I discarded the dill already into the yard waste.

Now that we know the chemicals used, do you advise getting the soil tested?

Thank you very much for your help.

On Monday, July 31, 2023 at 11:46:35 AM CDT, Ask Extension <<personal data hidden>> wrote:


The Question Asker Replied August 01, 2023, 3:58 PM EDT

No, I would not test the soil. It will dilute and wash through with rainfall.

You can go ahead and trim off the parts of the plants that are dying. They do have enough of a growing season left that they should recover.


Deb Reierson Replied August 01, 2023, 10:28 PM EDT

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