Very much related to nutrients, the pH level of soil affects how much of each nutrient is available to be taken up by plants. This is shown in the chart below where the pH level is displayed across the top and the width of the nutrient bands is indicative of how much of that nutrient can be taken up by the plant at that pH level:
In general, plants that require more iron, manganese and boron need more acidic soil. The optimal pH level for vegetable plants in general is 6.5.
Test your soil’s pH and compare it with the needs of the vegetables you’ve planted. Use lime to increase your soil’s pH level and use sulfur to decrease the pH. You can purchase pH testers, lime, and sulfur from most garden centres.