Yes, vinegar spider mites contact can kill these pests but it comes with big risks for your plants. The acid in vinegar burns mite bodies on touch. But that same acid also hurts your plant leaves if you use too much. It works as a quick fix but not as your main weapon against mites.
I tested a vinegar mite spray on my tomato plants last year when mites showed up. The mix killed some mites but left brown spots on my leaves within a day. My plants looked worse after the spray than before. Soap spray gave me much better results with no leaf damage at all.
The acid in vinegar breaks down the outer shell of spider mites on contact. This shell is thin and weak so even mild acids can tear it apart. The problem is that plant cells have thin walls too. When you spray vinegar on leaves the acid eats through both pests and plants at the same time.
If you want to try a vinegar mite spray keep the mix weak at 1 part vinegar to 3 parts water at most. White vinegar works best since it has a set acid level. Apple cider vinegar varies too much in strength. Never use full strength vinegar on any plant or you will kill the leaves fast.
Some plants handle acid worse than others. Ferns, orchids, and most herbs get hurt by even weak vinegar mixes. Roses and tomatoes can take a light spray if you rinse them after. Succulents and cacti have waxy coats that stand up to acid better than soft leaf plants.
When looking at home remedy spider mites vinegar ranks below soap and neem for good reason. Soap kills mites and does not burn your plants when mixed right. Neem oil both kills pests and stops eggs from hatching. Vinegar does less work and causes more harm in most cases.
My second test was on a jade plant that had a mild mite issue. The vinegar mix seemed to help at first with no leaf burn. But the mites came back in full force within ten days. I had to switch to neem oil to get rid of them for good. Vinegar just did not have staying power.
Test your mix on a small leaf section first and wait 24 hours before you spray the whole plant. Never spray in hot sun or the acid burn gets much worse. Early morning or late day works best when temps stay below 80°F (27°C). Rinse leaves with plain water an hour after your spray.
You can use vinegar as a backup if you have nothing else on hand. Mix it weak and spray in cool shade. But pick up some soap spray or neem oil as soon as you can. These work much better and do not hurt your plants like vinegar does. Save the vinegar for cleaning your house instead.
Read the full article: Ultimate Spider Mite Control Guide
