Hi Jennie,

Soap spray may cause damage that does not show up for a day or so. The new growth is more susceptible to burn by soap than older growth. The browning looks like injury that could have been caused by the soap spray. I am not familiar with Dr. Bronner's soap, but if is a people soap, it might contain additives that make it more pleasant for people such as fragrance and color, which may not be good for the plants. You might do better with soaps specifically formulated for use on plants. You will still need to watch the temperature and concentration to try to avoid burn. Otherwise your plants look very healthy with great leaf color.

Happy rose growing.

Hi Straw, I must confess that it never occurred to me that soap solution would be sprayed on the soil and therefore a soap toxicity might occurred and that it could be corrected by leaching. In fact we sometimes use a soap solution as a wetting agent when a pot becomes so dry that that soil actually repels water. I have never seen a problem with the roses after a wetting with a soap solution.

In my experience, the soap spray is applied directly to the pests which are on the leaves. I have seen foliage burn due to an application of soap solution and the photos look like soap burn.

I have grown roses in pots for many years and have never seen a calcium deficiency, but there is always a first time for everything.

The first photo is of a strawberry plant and the second appears to be spinach. I have found that it can be hard to diagnose a problem by trying to compare photos of plants of different genus or family.

Jennie: The white spots also look like rose slug damage. Calcium deficient plants are more susceptible to insect-invasion. The dark shoot-tip is typical of calcium deficiency in all crops.

See below the chemistry of soap and how it binds with calcium and magnesium, to form precipitates (aka soap scum) .. thus calcium is not available for plant uptake:

https://acswebcontent.acs.org/iyckit/booklets/L3_SoapScum.pdf

Below is a picture of calcium deficiency in lettuce:

Hi Straw; I enjoy reading your posts, your background in chemistry brings a unique perspective, and interesting information. The reason that I believe that damage is topical and possibility caused by the soap spray is that it "happened overnight". To me that would mean a chemical, such as something sprayed on it, or mechanical, such as insect damage. I have never seen nutritional deficiencies occur that fast.

Now your theory on the soap precipitating out calcium is interesting. However, I don't believe that the calcium was in a "solution" to begin with. If it were, then the rain would have washed it away without the help of soap. The link that you posted shows soap precipitating calcium out of tap water, so it seems to me that using soap could, in a very small way, add calcium to the soil by "unbinding" it from water. I truly don't believe that it was the problem because soap is used in agriculture as a "sticker spreader", a wetting agent and an insecticide and I have never seen any problems.

I would want to know the ph of the soil in the pot before adding lime to the soil. Too high a ph will cause deficiencies of minors.

Thank you all SOO much for your input. It helps a lot for me to consider the different possibilities of what might be happening.

I am going to test the pH of the soil this weekend and then try treating it for calcium deficiency. I may also spray a tiny section of a new leaf with the soap spray again to see if causes the same damage. Hopefully I'll be able to pin point exactly what caused the damage so I know for all my future rose growing.

Hi. I like your scientific approach to the problem. Please post the results, it's valuable information and could help others.