Strawberries, raspberries, blackberries, apples, blueberries that I grow are all sour! They are hardly edible. I have tried different types of fertilizer and the berries are in raised beds with good soil and full sun. I have tried many different varieties with the same result. What will help?
Certified GKH Gardening Expert
Sour fruit on almost all species is typically due stress on the plant. The most common cause of stress is either poor nutrition in the soil or watering issues.
While you have added fertilizer, you may not have added what the soil needs. I would highly recommend having your soil tested. This article will explain more about that:
Also make sure that the plants are getting enough water and that you are checking or other possible stressors such as pests or disease. But given that this is happening across all plants, nutrients or water are the likely culprits.