Ferrous Sulfate (Iron Sulfate) FAQ

1. What is the application rate of Ferrous Sulfate for lawns (St. Augustine grass)?

We would recommend using 2-3 Oz. (dissolve in 3-5 gallons of water for a foliar application) of Greenway Biotech Ferrous Sulfate (20% Iron (Fe) ) per 1000 sq.ft.

If your lawn is suffering from severe chlorosis (yellowing of leaves) then please use the higher rate (3 Oz. / 1000 sq.ft) and if your lawn is relatively healthy then please use the lower application rate (2 Oz. / 1000 sq.ft.)


2. How long does it take for Ferrous Sulfate to lower the soil pH level?

It really depends on a few factors and it is not the same in all circumstances.

For example, it takes longer to lower the soil pH level from 8 to 6 compared to 7 to 6.

However, in most cases, you should get your desired pH level after 2-3 weeks.


3. Can I use Greenway Biotech Ferrous Sulfate (Iron Sulfate) to make Iron Gall ink?

Yes, one of the ingredients to make Iron Gall ink is Ferrous Sulfate and you could certainly use Greenway Biotech's Ferrous Sulfate to make Iron Gall ink.


4. Can I use a hand spreader to distribute Ferrous Sulfate for a general application in a vegetable garden?

Yes, you certainly can. Greenway Biotech's Ferrous Sulfate could be applied to the soil (side dressing), dissolved in water and applied and/or as a foliar application.


5. Can Ferrous Sulfate be used in organic gardening?

No, Ferrous Sulfate is not registered with the state of California to be used in organic gardening.


6. If Ferrous Sulfate contains 20% iron and 12% sulphur, What is the other 68% comprised of?

 It is mostly water and oxygen. Almost all fertilizers contains water and oxygen and it is never included in the guaranteed analysis and only active ingredients are on the guaranteed analysis.


7. How soon after reseeding can I apply Ferrous Sulfate?

You could add Ferrous Sulfate to your soil before and right after seeding. However, we recommend applying it after your new plants are at least 2 inches long.


8. How much does 1 cup of Ferrous Sulfate weigh?

1 cup of Ferrous Sulfate weighs about 0.6 pounds.