The ph of my soil is 7,what can I add to bring it to around 6? From what I...
You are correct that the optimum pH of soil for most home vegetable production is 6.5-6.8. So you don't have far to go to lower your soil to the optimum level.
Do not add lime or wood ash. This will raise the pH above 7. We want to lower it. How to lower it will depend on the results of your soil test. Always get your soil tested before trying to change your pH. The test results will also give you fertility recommendations for what you want to grow. Sometimes you can serve both of these needs at the same time. Some common soil amendments that will lower the pH include pine needles, oak leaves, peat moss, and ordinary organic compost. If you already have plants growing in the bed, applying elemental sulfur is the way to go. Sulfur is very slow acting (it may take as long as 3-4 months to be effective). Applied at recommended rates, it’s safe for your plants. Another effective product is Iron sulfate. Iron sulfate acts more quickly (it takes about 2-3 weeks to affect the pH) but you have to use more of it. Other additions for acidifying the soil include cottonseed meal, ammonium phosphate, or even coffee grounds. Commercial fertilizers like Miracid are formulated for plants that lilke acid soil but it will not lower the pH. Fertilizing with ammonium sulfate is powerful and effective, can easily burn plants if not used carefully. With all products read the lables carefully.