Down To Earth All Natural Fertilizers Organic Acid Mix - Plant Food for Blueberries, Raspberries, Azaleas and Rhododendrons 4-3-6, 5 lb

I wouldn’t add any more then. My PH is at 6 and my plants are thriving. Probably best to do that gradually. For fertilizer I use this stuff: https://a.co/d/0f7b2Cvl. It does more than acidify which I think will help if the plant is stressed. Just from my experience but the ones I have now are doing really good, no fruit yet but the plants are really popping off. I’m sure others will tell you different but in my experience, slow and steady beats fast and harsh with these plants in general. DM me if you want to talk more specifics.