How To Remove Iron Stains From Concrete In The Garden

Pinterest Hidden Image

Have you ever tried to remove iron stains from concrete? Iron stains can make a beautiful garden pathway look very unattractive.

Concrete is porous, making iron stains easy to penetrate the surface, requiring scrubbing to remove. A variety of sources leave rust stains when they come into contact with your concrete driveways and walkways.

remove iron stains from concretePin
remove iron stains from concrete

Leaving a bike lying on the surface or old garden tools left out in the rain can leave iron stains or even oil stain on concrete. The rust stain will not wash away by simply spraying warm water on the surface.

Old and stubborn stains will need stronger substances to clean them while newer rust stains can easily be removed by the use of natural cleaners.

Using of chlorine bleach is not recommended as it will only make the rust stain worse. There are many causes of rust stain on your concrete. Let’s look at a few causes of rust stains we find in the garden.

Read on to learn more about how to remove rust stains from concrete.

Ironite Fertilizers Contain Iron

Iron fertilizers contain iron sulfate which can stain your walkway. Sometimes a fertilizer bag can cause a nasty stain when placed on a concrete walkway.

The stains they cause can be difficult to remove using your daily household products. You can use concrete rust stain removers that are readily available at home improvement centers.

You can also choose from the chemical stain removing methods or the natural or homemade methods.

There are times you may want to create an “aged” look to a walkway.

Exposed Metal Rebar

A metal rebar is used to reinforce the concrete sidewalks and foundations. If it is exposed, it will slowly rust and may cause stain to the concrete.

Remember to seal the concrete after removing the rust stain to prevent it from further damages.

Iron-Rich Well Water Used For Irrigation

For people irrigating using well water, it can be very difficult to control iron staining a walkway.

It’s common for the stains to appear on driveways due to the build-up of rust.

When watering your plants or shrubs, rust builds up over time leaving behind the orange mark which can turn your beautiful walkway into an eyesore.

It’s recommended you set the irrigation spray heads to reduce the spray of water from splashing on your walkway.

Although it may be difficult, try as much to avoid spraying your walkway concrete with water that has high levels of iron.

Metal Furniture Placed On Concrete Patios And Walkway

When metal furniture is placed on patios or concrete walkways it can leave rust marks on the floor. These marks can go for a long time without being noticed until the furniture is moved.

Maintaining a good coat of paint on old furniture will help with this problem. If by chance you notice “rust” beginning on the patio furniture, use the wire brush to remove it and repaint the furniture.

The Concrete Aggregate Used

The aggregate used to make the concrete may contain iron oxide or the rebar which may be too close to the surface.

Most homeowners believe the problem originates from the installation of the stone concrete.

This is no always the truth. The iron oxide is responsible for the stain on your walkway.

Solutions To Remove Iron Stains On Concrete

Using A Wire Brush And Water

Before you embark on the use of chemicals to remove iron stains from concrete, you should first use this easy method.

It doesn’t require much work. Just pour water on the rust and brush it out. This method works on the stain that have not penetrated the concrete deeply and is only on the surface of the walkway.

The Use Of Tri-Sodium Phosphate

Following the procedure below will work best when using Trisodium phosphate [amazon].

  • Wear rubber gloves to protect your hands and goggles to protect your eyes. Trisodium phosphate can cause irritation to the skin and eyes. It can also be harmful if it is ingested or inhaled.
  • In half a gallon of hot water, mix half a cup of Trisodium phosphate and wait until it dissolves completely.
  • Pour the solution onto the iron stain until it is fully covered. Leave it to set for about 15 minutes to ensure the Trisodium phosphate penetrates the rust.
  • Use a wire brush to scrub the area. The scrubbing should be done in a circular motion and at the same time applying firm pressure to the brush so as to loosen all the rust that is within the concrete.
  • The area should then be rinsed using clean water to wash away the solution. If the rust has not disappeared, repeat the application of the solution and scrub the concrete once more.

Using Oxalic Acid For Iron Stain Removal

The procedure to follow is as below:

  • Oxalic acid is extremely caustic and therefore you have to wear goggles and rubber gloves to protect your eyes and hands.
  • Mix four ounces of oxalic acid in a quart of water. Oxalic acid comes it the form of crystal or powder in most of the paint stores.
  • Use a mop to apply the solution to the stain and leave it for two hours for it to penetrate into the concrete floor.
  • Use a stiff brush to scrub the area and then rinse the area with clean water. You may have to repeat the process for some time depending on the severity of the stain.

Using Lemon Juice

  • Pour undiluted lemon juice over the rust stain. Make sure all parts of the rust stain are well covered. Caution should be taken when treating an area that is close to grass or valuable plants since undiluted lemon juice can cause harm to your plants.
  • Allow the area to rest for 15 minutes to allow the lemon juice to penetrate the concrete. This gives time for the rust to be broken down which makes scrubbing easier.
  • Use a wire brush to scrub, using a circular motion. Apply firm pressure when scrubbing so as to loosen all the rust within the concrete.
  • Wash away the lemon juice with clean water. Repeat the procedure if the stain is not fully removed.

Apple Cider Vinegar & White Vinegar

  • Any of the types of household vinegar can be used to remove unsightly rust stains.
  • Pour or spray undiluted vinegar on the stain and allow to settle for about 15 minutes.
  • Scrub the area using a sturdy bristle brush and then rinse off the vinegar and stain away.
  • The same as lemon juice, vinegar can also cause damage to foliage and therefore care should be taken when using to close to grass or plants.

Using Hydrochloric Acid

Also known as muriatic acid, it is one of the best cleaning agents for rust. However, you will have to clean the whole concrete surface as it will change the color of the surface.

Make sure to stick to one chemical as well as one chemical strength as much as possible to avoid getting rivers of different colors on your walkway.

The muriatic acid should be diluted down from 45% to 4 or 5 parts of water in a plastic bucket. The solution should have at least 10% acid not unless you need it in full strength.

Remember when diluting acid, you should add acid to water and not water to acid to avoid having an exothermic reaction.

If the rust stain is really stubborn, you can pour the acid straight out of the bottle which is 45% acid. Rinse the area carefully with pressure washer for about 1 minute.

Do not wash for long as it can leave a nasty stain, acid on the concrete. Use baking soda to neutralize the acid runoff.

When using HCL make sure to wear protective clothing such as goggles, rubber boots, vinyl gloves, long pants and long sleeve since it is very dangerous.

Scrubbing should be done with water to avoid particles of acid flying towards you. Also avoid as much as possible breathing in the fumes produces by the acid.

If you can’t get access to the above iron stain removers, you may lean to other materials that can also remove rust stains. Some of these rust removers include diatomaceous earth powder, hydrogen peroxide, and fuller earth.

In conclusion, it is important to mention that some of the methods described can be dangerous if not carefully used. Read the use instructions and make sure that you adhere to the amounts mentioned in each one of them. Don’t forget the protective gear that must wore before embarking on the stain removal. Do the “cleaning” in a well-ventilated area.

Read the directions carefully and if you feel there is something you did not understand, contact a professional to do the job for you.

Also, if a mishap happens, wash the part where the chemical has touched with plenty of water and seek further medical attention from a qualified doctor. Always remember to stay safe at all times

Sources: 1 | 2 | 3 | 4 | 5 | 6

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.