The ideal soil pH for growing green beans is slightly acidic to neutral, ranging from 6.0 to 7.0. If your soil is too acidic, you can add lime to raise the pH. On the other hand, if your soil is too alkaline, you can amend it with organic matter like compost or peat moss to lower the pH. Testing your soil's pH level with a soil testing kit can help you determine if any adjustments are needed.