Algaecide is often a copper-based product and copper can have a pronounced effect on the quality of a lawn. A copper deficiency can lead to a washed-out appearance and failure to thrive but what happens if you suddenly splash copper-rich water onto that same lawn? Will algaecide kill grass or make it grow just a bit better?
Will Algaecide Kill Grass?
No, in the concentrations recommended for use in pools, algaecide will not kill grass. However, if applied directly and not cleaned up or sufficiently diluted, a heavy application of a copper-based solution will stunt root growth and lead to increased photo-sensitivity in nearly all types of grass and many other garden plants.
What Algaecide Will Do to a Lawn
Algaecide can have a number of effects on a lawn ranging from improved visual appearance to heavy metal poisoning. A direct splash of algaecide onto a lawn straight from the bottle or jug should always be diluted at least 5 to 1 water to algaecide.
This much direct contact with a copper-based algaecide can stunt root growth and, as it is absorbed, will cause photo-sensitivity. This means that grass will appear “burnt” at the tips and may develop either a brownish hue or a washed-out appearance tipped with brown.
In some cases, lawn care professionals have been known to spray a lawn with a very light application of algaecide. In areas where it is often damp and humid, this is the only way to keep a large lawn lush and free from algae and moss as these are quick to develop in valleys in these conditions. This application is always done with the utmost care and copper levels in the soil are frequently monitored. This process should never be done in a dry region or where irrigation is limited.
Related Article: What Kills Grass?
Will Pool Algaecide Kill Grass?
Pool algaecide is often primarily copper-based and should never be applied directly to a lawn. After it has been diluted in pool water, any residual chlorine in that water is more likely to harm your grass than the algaecide would.
The problem is, many pool-specific algaecides are combination products. This means that the algaecide is mixed with other pool sanitizing chemicals or is a more potent mix of these chemicals alone and the product contains no copper. In this case, where the primary ingredient is chlorine or bleach, the “algaecide” will kill your lawn if a spill or splash is not immediately, heavily diluted.
However, copper-based pool algaecide should not harm your lawn if there is a small splash or spill. Yes, care should be taken to dilute the solution but any effects this may have on your lawn will be slow to appear as plants, including grasses, should be slow to absorb the solution.
Algaecide’s Effect on Landscaping
While your grass lawn may be safe from the effects of algaecide, not all plant life is safe from the effects of this type of product. Moss lawns, for instance, will be decimated with even a light application of algaecide or a small accidental spill.
Further, while grass will “get rid” of copper as grass blades are shed over the course of a few months’ worth of mowing, other plants will hold onto that copper. Trees, for example, can develop heavy metal poisoning after several exposures to copper-based algaecide.
How to Clean Up an Algaecide Spill
If algaecide has spilled or splashed onto your lawn, the best thing you can do is attempt to dilute the solution to the point where it is harmless. This is best done with a garden hose or several large buckets of water. A ration of 5 parts water to 1 part spilled solution is a good rule of thumb. Once the solution is sufficiently diluted, there should be no foam, smell, or visual traces of algaecide. There should be no notable effect on the soil after this process.
Algaecide Isn’t Safe for All Lawns But It Shouldn’t Kill Most
While copper-based algaecide is immediately deadly for most algae and mosses, it takes time for it to affects grasses. This is primarily why this type of algaecide has some lawn-care applications in cases where algae and moss have overrun a yard. While this is not a recommended practice, and a better alternative is often to adjust the pH and nutrient balance of a lawn, the algaecide is easy to dilute to the point where it is not harmful after application.
In the case of pools, algaecide is often the least harmful chemical you could add to pool water before draining it on your grass but only if it’s copper-based. Other bleach or chlorine-based algaecides will kill grass and other plants just as pouring these substances directly on your lawn would. To control this type of algaecide, dilution is still recommended but you will need to use a much higher ratio of water to chemical algaecide.
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