Moss on lawns is a common problem in gardens and landscaped areas, especially where it's damp, shady, and the soil is dense or acidic. Two popular chemicals used to control moss on lawns are Iron Sulphate (also called Ferrous Sulphate) and Benzalkonium Chloride (BAC). Both work to kill moss, but they affect surfaces differently, especially when it comes to staining concrete and paving.
Iron Sulphate has been used for a long time as a fast-acting moss killer. Iron Sulphate will kill moss quickly when used on lawns. It can turn the moss black/brown within several hours to one day.
Iron Sulphate will also provide iron to the grass, making it appear greener when used as part of a lawn treatment.
Disadvantages of Iron Sulphate include:
- It can cause coloured stains on concrete, paving stones, patios, and deck surfaces.
- These stains are generally quite difficult to remove.
- Wherever it drips onto any area, including driveways or walkways, it will likely cause permanent discolouration.
- Over-application can also be harmful to grass.
Due to staining concerns, many property owners apply Iron Sulphate very carefully, especially around hard surfaces such as pathways, tiles, and concrete driveways.
Advantages of Benzalkonium Chloride include:
- It will not leave rust stains on either concrete or paving.
- It is considered a safer product to use around patios and driveways.
- The effects of Benzalkonium Chloride provided by pest treatments last, making it less likely for moss to grow back.
- Benzalkonium Chloride kills algae and mold as well.
Due to these benefits, the product is commonly used professionally for moss treatment of lawns, roofs, and all other outdoor surfaces.
So, which one is better?
Iron Sulphate is an effective and efficient treatment for killing off moss; however, because of its ability to leave a permanent stain on hard surfaces that are adjacent to the areas being treated, it is not an ideal application method for many homeowners.
A number of lawn care professionals recommend using Benzalkonium Chloride instead of Iron Sulphate for controlling moss because Benzalkonium Chloride does not leave permanent stains and provides a cleaner alternative for controlling moss than Iron Sulphate does.
Conclusion:
Overall, both Iron Sulphate and Benzalkonium Chloride are effective at killing moss in your lawn, but they offer different qualities. Iron Sulphate is fast-acting and is capable of killing moss quickly; however, it also has the potential to stain any hard surfaces in its path. While Benzalkonium Chloride takes longer to kill off moss than Iron Sulphate, it is safe to use around hard surfaces and other buildings where the moss may be growing.
For this reason, many homeowners prefer to use Benzalkonium Chloride as a cleaner and more long-lasting option to kill moss than Iron Sulphate.