Monterey Dr. Iron Soil Acidifier

Before applying, you should use a soil pH test kit to confirm your soil is alkaline. If your plants—especially acid-loving varieties like blueberries, azaleas, or hydrangeas—show yellowing leaves despite regular watering, it is a strong indicator that the soil pH is too high and preventing nutrient uptake.

You can use it on both. It is particularly effective for lawns struggling with yellowing or poor growth due to high pH, as the iron content helps restore that deep green color while the sulfur works to correct the soil chemistry over time.

While the iron provides a relatively quick boost to leaf color, the sulfur component works more gradually to lower the soil pH. You should expect to see noticeable improvements in plant vigor within a few weeks, though long-term soil adjustment takes time.

Yes, like any soil amendment, it is important to follow the application rates listed on the label. Applying too much can alter the pH too drastically or cause nutrient imbalances, so measure carefully and water the granules into the soil thoroughly after application.

For established plants and lawns, you can spread the granules on the surface and water them in well. If you are preparing a new garden bed, mixing the granules into the top few inches of soil will help the sulfur begin working more efficiently.