DITO; Don't use vinegar around them. If anything use a lite solution of peroxide. Try fresh potting soil. It may have the problem fixed. I have an old school mix I use that My Gramps used back in the day that I can not use this Year because I am doing a log for FAST2GROW. It works great. Dissolve one teaspoon each of Epsom salts, Salpetre, and Baking powder (not soda) along with 1/4 teaspoon houshold ammonia in a gallon of water then shake it up. Spray them when they start up and water them every six weeks with it. grgfinney can direct You to the salpetre if You cant find it. You have to mix all the ingr. to work.