Pure hydrochloric acid is deadly to many organic substances on contact. Muriatic acid is a diluted, impure form of hydrochloric acid. However, is muriatic acid diluted enough to be safe to use on its own? Or will muriatic acid kill grass on contact? No matter if it was spilled accidentally or sprayed intentionally over a problem area, muriatic acid can cause problems.
Will Muriatic Acid Kill Grass?
Yes, muriatic acid will kill grass. If full-strength muriatic acid comes into contact with any plant life, it will cause damage. This damage will likely cause the death of any small plant, including grass and most common varieties of weeds, bushes, and flowers.
What Does Muriatic Acid Do to Grass?
If muriatic acid is allowed to splash directly onto the foliage of a plant, it will cause chemical burns and may burn straight through portions of the plant. If muriatic acid is allowed to drain into the soil, the acid may leech onto plant roots and kill plants by starving them of water and nutrients.
Muriatic acid may stay in the soil for several days at unsafe levels. Efforts should be made to clean up or neutralize any muriatic acid spill as soon as possible.
Related Article: What Kills Grass? The Complete List
Will Diluted Muriatic Acid Kill Grass?
Muriatic acid can be diluted to levels where it’s less likely to cause harm to grass. However, it’s almost impossible to dilute muriatic acid to that point after spilling it on something. Once the muriatic acid has come into contact with a plant, there will be consequences, no matter how quickly the acid is washed off.
Can Muriatic Acid Kill Grass and Weeds?
Muriatic acid can be used to easily kill grass and weeds. Muriatic acid is also prone to splashing, is difficult to control, acidifying, and may leech into the soil and affect nearby plants. Though it’s possible to use muriatic acid as a herbicide, there are alternatives available that are less expensive and less harmful to plants, people, and local ecology.
How to Safely Dispose of Muriatic Acid
Given all of its dangers, muriatic acid is still a remarkable cleaner, especially if you need to clean patio furniture, tiles, concrete, or vinyl siding. When you’re done cleaning there are just a few things to keep in mind so you don’t get any unhappy surprises hours or days later.
Can I Pour Muriatic Acid on the Ground?
Muriatic acid can be messy even if you’re only using it to wipe down furniture on a cement pad. A good rule is to always neutralize muriatic acid as soon as you’re done using it and then rinse any surface that the acid touched. You should then rinse any nearby plant life and any area where there is runoff from either the initial wash or this rinse. This process can help prevent the muriatic acid from binding to the roots of plants or causing discoloration as it is exposed to sunlight over time.
Can I Pour Muriatic Acid Down the Drain?
Pouring muriatic acid down the drain, diluted or not, will corrode pipes very quickly. It does not matter what these pipes are made out of, muriatic acid should never be poured down the drain.
How Do You Neutralize Muriatic Acid?
Muriatic acid is best neutralized by adding baking soda or lime to the diluted acid. It is best to only neutralize this acid if it has spilled or is no longer in its original container. Alternatively, many counties have hazardous waste disposal centers that will walk you through the steps of neutralizing and containing this acid until you are able to bring it in for disposal.
How to Clean Up a Muriatic Acid Spill on the Ground
If muriatic acid has spilled on your lawn or soil, it is best to immediately neutralize the acid with a base. Common sodium bicarbonate or baking soda is a good first resort. Calcium carbonate or garden lime is a more effective choice.
Once the dry baking soda or lime has been applied, carefully add water to the area in order to dilute the liquid. After about 15 to 30 minutes, it should be safe to add sand or dirt over the spill and allow it to dry. Any plant life caught in the spill will likely die back. It is best to wait for several days and then test the acid content of the soil. Correct the pH as needed before replanting.
How Does Muriatic Acid Affect the Soil?
Muriatic acid acidifies soil and will kill anything living that it can reach before being neutralized and diluted. How long it takes to correct these effects depends on the original pH and mineral content of your soil.
Muriatic Acid Shouldn’t Be Anywhere Near a Lawn
Muriatic acid is strong stuff. It’s often heavily diluted before being used to clean with but if used straight from the bottle, even the fumes may cause some plant life to brown. If the acid does come into contact with your lawn, you will have a brown patch and need to amend the soil to correct the pH. After several weeks, there should be no persistent problems.
Good day ❤ bro. Can I mix muriatic acid with salt to make it more active to kill grass?
Hi Paschal!
In short, no. Adding salt to muriatic acid will not make it more effective.
This is a great question. As muriatic acid is somewhat “salt” based it seems plausible that adding salt could make it more effective. However, the more effective and grass-killing component of muriatic acid is the chloride element while the salt sort of helps it along. Adding more salt in a reasonable concentration like 1 cup per gallon may only increase the muriatic acid’s effectiveness by .0001% or so. Though the salt itself could kill some plants, it can also build up in the soil, especially if used in high concentrations like this and may prevent plant life from growing well in those areas for a long time.
I hope this helps you 🙂
If you want totally DEAD forever and dont want to use the carcinogenic Roundup chemical, a good concentration salt in the muriatic acid and some dish soap will do a serious number on the weeds, grass etc.
I have a 60×50 play area for my dogs filled with 3″ of sand, before I put the sand in I spread out several 40# bags of rock salt because I want it to be a totally DEAD wasteland under the sand with nothing popping up. The acid will burn the weeds/grass fast, the salt will soak in and get into the roots and stay. I expect I’ll periodically need to spread more rock salt out, but it’s working well.
Vinegar and salt with dish soap works too and is cheap. With the green part of the weed etc dead the roots can’t get any nutrients from the sun either, as long as you keep the green from re-emerging the roots will die- all weeds and grass has a lifespan. Different types of grass have different lifespans. However, common turfgrasses live about 3-5 years before dying. An individual blade of grass lives around 40-50 days, so after keeping the green from growing the root is going to die off.
Hi RDW,
Thanks for getting involved and contributing 🙂
Using rock salt under any area you want to be completely dead (and stay that way for years to come) is a great idea. However, rock salt is also a known hazard for pets. While 3″ of sand may seem like a good barrier, it may mix with the rock salt over time and result in burnt paws or even salt toxicity if the pet regularly licks their paws.
To help prevent this as the rock salt is already under the sand, you may want to increase the volume of sand and top it up periodically as it mixes into the sand and salt underneath (due to the agitation of walking or playing on the sand. Rock salt can be dangerous to humans (including children) in a similar way though it may take longer for any adverse effects to show up.
Roundup is a probable carcinogen and I always recommend using full safety gear when handling it. The same safety gear should be used while handling muriatic acid as, though no link to any cancer has yet been found, the substance can cause burns to the skin and eyes or even lung damage or kidney failure if handled improperly. Adding salt to the muriatic acid, as explained in my other answer, will not increase its effectiveness by any realistically measurable amount. Adding dish detergent, while not dangerous, has a mild nullifying effect on the muriatic acid. I would advise against this add-in.
Mixing vinegar with natural dish soaps will also have a nullifying effect on both substances. Mixing vinegar with a dish detergent will have a milder effect but will still cut down on how well either substance kills grass. I suspect the results you are seeing come primarily from the detergent and salt combination. Vinegar, added to any homemade weed killing solution I have seen, usually cuts down on the effectiveness of a “formula” as it does not kill weeds on its own. Dish detergent can kill weeds and a small amount of it mixed with saltwater can help the saltwater better penetrate the blades of grass, killing them in the way you have described.
I hope this helps clear things up and helps keep everyone safe!
Cheers, Tom.
Because cleaners containing muriatic acid come in plastic bottles, is it safe to assume a diluted solution would not damage hand held sprayers?
Hi A,
If your sprayer has any metal parts inside, then it’s going to be a problem if it comes into contact with the muriatic acid. This type of acid is extremely corrosive and will completely eat away metal. So, if you have a metal sprayer tip, then it’s going to eat it up pretty quickly. Also, if you handle muriatic acid, be sure to use gloves, protective glasses, and a good quality respirator. This stuff can be deadly.
Thanks for your comment.
Cheers, Tom.