Question:
How do I clean a terra-cotta plant pot?
Terra
-cotta pots offer a beautiful and natural home for all kinds of plants both indoors and out. The porosity of these clay containers offers many advantages for growing strong and healthy plants. However, since terra-cotta containers can absorb water, they also absorb minerals from the soil and chemicals in the fertilizers. It is essential that they be cleaned and sterilized at the end of each season to keep from these absorbed particles from being spread to new plants in the spring. It also helps to get rid of any fungus or mold that has developed so that it does not infect the plants or damage your container.
Steps for Basic Cleaning
Cleaning your pots regularly will keep them looking and functioning at their best.
You Will Need:
- Scrubber (any kind of stiff brush, steel wool or plastic scrubber will work)
- Baking soda
- Water
- Soft brush
The Cleaning Process:
- Remove old plants and as much soil as possible from the terra-cotta pot/container.
- Allow the remaining soil to dry thoroughly so it will be easier to remove.
- Using the scrubber, brush away as much of the build-up from the inside of the pot as possible.
- If necessary, carefully wash out the inside with water and the scrubber. Avoid using soaps as this can leave a residue that can be difficult to remove.
- Salts that are found in water and fertilizers can leave a white crust on the outside of the pots. To remove this build up, make a paste from baking soda and water. Spread the paste over the build up and use the soft brush to gently scrub it away.
- Rinse the pot thoroughly and allow to dry completely.
Removing Mildew
This process can be used on any size of planter and is very easy. There is no need to remove the plants.
You Will Need:
- White vinegar
- Water
- A pitcher or spray bottle
Steps to Remove the Mildew:
- Combine equal parts white vinegar and water in the container of your choice. For larger planters, you may want to use a pitcher so the solution can be poured over the sides as squeezing the trigger on a spray bottle could get tedius. If you have hard water that typically leaves a hazy white film on surfaces, use distilled water instead.
- Apply the mixture to the sides of the planter. Try not to get any of the liquid on the soil; although this remedy is all natural, some plants prefer a more alkaline soil and will not be pleased with the acid in the vinegar.
- For thin layers of mildew, no further action may be needed – the spray can be allowed to dry on the planter and will kill the mildew.
- If the mildew is not gone after the spray has dried, a second application can be done, this time also scrubbing the sides of the planter with a soft scrub brush or cloth.
- Rinse the area with water after scrubbing off the mildew, then apply the spray to the area again and allow it to dry.
Sanitizing with Bleach
Sanitizing the pots will help to remove any fungus (mold) that may be harmful to your plants.
You Will Need:
- Water
- Bleach
- Bucket, tub or basin (must be larger than the pot your are sanitizing)
- Trash bags (for pots too large to fit in a bucket or tub)
- Sponge or Cloth
- Scrubber
The Sanitizing Process:
- Begin by cleaning your container following the instructions above.
- Fill the bucket with a mixture of 10 parts water and one part bleach. Bleach can cause wear on a pot if too much is used, so use it sparingly. Less is more in this situation. (For pots that are too large to fit in a bucket, sturdy trash bags can be used instead. If the pot is so large that you will need to tear the bag to release the water afterward (rather than lifting the pot out of the bag), keep in mind that bleach can damage a lawn or deck, so be sure to do this cleaning on a concrete driveway and rinse the area thoroughly afterward.)
- Place the cleaned pot into the water/bleach mixture. Be careful not to put a cold pot into warm water or vice versa as the change in temperature may crack the clay. If using a trash bag, tie it shut over the top of the pot.
- Allow the container to soak for at least 30 minutes. If your pot is especially grimy, you may want to soak it for longer.
- Use the scrubber and/or sponge to remove any remaining dirt from the surface of the pot.
- After the container has finished soaking, drain it thoroughly and transfer it to a bucket or trash bag filled with plain water. Allow it to sit for another 30 minutes. Bleach can be harmful to plants, so try to remove as much as possible. Repeat the rinsing soak as many times as needed using fresh water each time to remove all the bleach.
- Drain again and allow the pot to dry completely.
- Now your pots are cleaned, sanitized and ready for another season of use.
Sanitizing with Heat
If you want to avoid using bleach on your terra-cotta, you may want to try using heat to destroy any bacteria and fungi. Use the method below for pots that are small enough to fit in the oven. If your pot is too large for an oven, the next best option for sanitizing with heat is to put it in a black trash bag and leave it in your locked car on an exceptionally hot summer day. This method will not be as effective as the oven method listed below, but it can still kill the majority of bacteria and fungi.
You Will Need:
- Oven
- Aluminum Foil (optional)
- Plenty of time
The Sanitizing Process:
- It is best to use this method when the weather is still warm enough that you can keep the windows open. Baking your soiled pots may create an unpleasant odor.
- Begin by cleaning as much dirt as possible from the pot using the instructions above.
- When the pot is completely dry, place it inside of the oven.
- If there is any dirt remaining in the container, you may want to line the bottom of your oven with aluminum foil to keep the dirt from baking to the floor of your oven.
- Turn the heat up to 220º Fahrenheit.
- Allow the clay to bake for at least an hour to kill any harmful growth.
- Turn off the oven and allow the clay to cool completely before trying to move it. This may take some time, but moving it while it’s hot may cause the pot to break.
Cleaning Without Removing the Plants
You Will Need:
- Cardboard
- A scrub brush
- Water
Steps to Clean the Pot:
- If you need to clean a pot while the plant is still in it, first start by cutting a piece of cardboard to the same size and shape as the top of the pot.
Cut out a hole for the plant stalk from the piece of cardboard, and cut a slit from the stalk hole to the closest edge. This will allow you to basically put a cap on the soil so that it is contained while you tilt the pot for cleaning. You can wrap the cardboard with plastic wrap to keep it from getting wet while washing the pot if needed as well. - Brush off the dirt on the outside of the pot with a scrub brush.
- If needed, wash the outside of the pot with plain water, using the scrub brush to scrub off any dirt.
Additional Tips and Advice
- If you are hesitant to use bleach, consider trying white vinegar. Be sure to rinse it thoroughly as well.
- If you are preparing your pots for winter, ensure that they are completely dry. If they still have water in them and it freezes, it could cause them to crack or break.
Rather than bleach, heat or vinegar, hydrogen peroxide (3% strength sold in drug stores & even cheaper in dollar stores) is one of the best & safest disinfectants there is. Basically, it oxidizes or breaks down any fungi or bacteria left behind. It’s also great for removing stains from most things (carpets, fabrics, tea or coffee cups), but test on colored fabrics first for color-fastness. The 3% strength isn’t very strong & rarely removes color from rugs or fabrics unless the dyes are cheap. Peroxide is safe too (except to ingest) as it’s simply water (H2O) with an extra oxygen atoms tacked on to become H2O2.
Several terracotta pieces hanging on our courtyard wall have either faded or look as though they had a light white wash applied. We live in GA, so realize the sun probably permanently bleached a couple of pieces. We thought the white might be lime so I just tried lime-away and nothing changed. Any suggestions? Thanks, Joan
Joan,
You can try using some of Diana’s ideas for mineral deposits to see if those help, or give the pots a good general scrub and cleaning. If cleaning doesn’t restore the color, you can dye them using some of the great ideas from Jude’s comment on this page, Jude. Another option is to paint them – here is a guide to painting terra-cotta pots from FineGardening.com. Good luck!
Why not use a suitable stain for your terra cotta pots? Since clay is very porous, it absorbs colours well. You mention wall art so I assume they’re not meant for plants, although there are safe pigments meant for clay pots that don’t harm plants. If yours are only decorative, choosing a wood stain in the closest colour to match the original colour would work. I can’t guarantee it wouldn’t have to be done every year but still, once yearly isn’t bad to keep it looking the way you’d like. Experiment on the back of the pieces first to see how it dark it gets.
To get rid of white mineral stains, first scrape away the loose soil and rinse out any remaining dirt. Then fill a bucket with warm water deep enough to immerse the pot and add enough vinegar to make a 4:1 solution (1 cup per quart). Soak the pot in the solution for at least 1/2 hour, longer if a crust has formed. Then wipe or scrub away any remaining crust. If the pot is very crusty, you can repeat the treatment with a fresh solution. Be sure to rinse the pot thoroughly afterward, because some plants don’t tolerate acid. Note: Vinegar cleans but doesn’t sanitize.
Hi Margie,
Have you found a way to remove the paint from your pots? I am trying to work on the same thing. I have a very large terracotta pot that I painted last year. It unfortunately sat at the end of my garage all winter. It would snow and melt and the water would get into the garage and get on the pot. I had sealed the pot with urethane, but it bubbled and started to peel. I’ve removed a lot, but I can’t figure out how to remove the rest.
I just received a large terracotta pot and my question is; do I season the pot with oil before I plant it?
Patsy,
There are pros and cons to oiling the planter. Basically the decision to oil comes down to what the winter situation for the planter will be, though considering the watering requirements of the plant you want to use the planter for is also a good idea.
Pros:
One of the main reasons oiling is done is to help prevent terra-cotta planters from cracking in winter. The reason they crack is because they are porous and absorb moisture, which therefore expands into ice in freezing temperatures, causing the clay to crack. If your planter will be indoors or if you don’t mind moving it somewhere dry for the winter, then oiling for this purpose is not necessary.
Another reason that you may want to use oil is to prevent the clay from absorbing water is that it can prevent the commonly seen white limescale deposits on the outside of the pot. The limescale can be cleaned off, but the oil prevents it from occurring at all.
Cons:
Alternatively, potting soil expands when it is watered. By oiling the pot inside and out to prevent it from wicking up moisture, it could crack due to the expanding soil instead.
Oiling the pot to prevent moisture from entering the clay also prevents air from entering the clay, which is one of the reasons clay planters are considered superior planters (they allow the plant roots to aerate similar to how they would in soil).
The terra-cotta wicking water away from the soil is helpful for plants that are easily damaged by overwatering, especially if you have a heavy watering hand. Oil would remove the ability for the plant to help safeguard against excess moisture.
Oddly, the wicking ability also helps to provide better moisture to plants that require it. Though the clay does wick water away from the soil, which is useful for excess water, it also retains that water and therefore allows the soil to stay moist for longer. If you are likely to underwater the plant or if the plant prefers moisture, you may not want to oil the planter.
Source: YouTube – How to Prevent Clay / Terra Cotta Pots from Cracking The Easiest Way
Source: University of Nebraska – Lincoln – Choosing a Clay or Plastic Pot for Plants (typeofpots)
Source: SFGate – Tips on Using Terra Cotta Pots for Houseplants
I just used the peroxide tip from Jude on my large terracotta pot to remove green (moldy-looking) grime. With a little elbow grease (not really much at all) and a scrub brush, my pot is looking pretty good. 🙂 Thanks for the tip!
I have a terracotta Picasso tile. It is very valuable and I need to sell it. There are a couple of grease stains on it. Does any one know how I can get rid of them? I’m afraid if I put it in the oven it will break.
You could try rubbing the stain with a grease-cutting dish soap or a mixture of vinegar and water.
Source: HowToCleanStuff.net – How to Remove Grease Stains from Painted Walls and Ceilings
You could also try using talcum powder to draw the grease out of the tile.
Source: HowToCleanStuff.net – How to Remove Grease Stains from Leather
Can you seal terra cotta pots?? Will it affect the plants?? I live in Florida and have a very large terra cotta pot in my back yard, and I hate to clean it every year… What can I use to solve this problem????
Thank you in advance.
Someone has thrown something on my potted clay pots and they look bad. How do I clean them? Can anyone help?
I have huge terra cotta pots that hold hibiscus trees, etc. They are outside and have mildew on them and are looking black instead of their beautiful natural clay color…WHICH cleaning method is best and won’t kill me cleaning all of these? There are six of them. Oh, and I read how to clean the INSIDE, but my concern is the OUTSIDE of the pots.
Thanking you all who answers.
Kathie,
The article has been updated to include a section on Removing Mildew that addresses larger planters. Good luck!
I have a beautiful clay pot with elegant roses on the front. I bought two at an antique sale; one just needs to be cleaned, the other has about a 12 inch hairline crack starting at the top. Is there anything I should or can do to the hairline crack to stop it from running or should I leave it alone? Should I just set a plant in it or do you think I can plant it it? Thank you.
Ellen,
It would be best to just set a plant in the cracked planter with it still in its plastic container. By replanting the cracked clay one, it will put the pot in greater danger of continuing to crack or fully breaking. Soil expands as it absorbs water, which will put pressure on the pot. Also, clay pots wick moisture from the soil, which then expands in freezing winter temperatures and causes the cracks to form.
In terms of stopping the crack, you can glue it back together. Some places recommend wedging a toothpick into the crack so glue can be applied deeper inside of it, or you can simply wipe a line of glue over the crack. Depending on the color(s) of the pot where the crack is, you could use a white glue if the pot is white to help also hide the crack, or use a clear glue if the area is colored.
Good luck!
Source: SFGate – How to Fix Cracks in Terra Cotta Flower Pots
Source: eBay – How Can I Repair Chipped or Cracked Pottery
We would like to clean the exterior of our African violets’ terracotta pots, without harming the violets. What do you suggest?
Thanks, Warwick
Thanks for all the tips. I just discovered the previous owners of the house we moved into left large terracotta pots under the trees. They are old and I will use your ideas to make them nice and new.
Terracota is the best thing for plants.
Bushra
I have four 12″ and one 14″ terracotta pots and need to clean/sanitize them. I think they are a little too big to soak. Is there another way? I’m more concerned with cleaning the inside and keeping my new plants healthy than with the outside. The peroxide idea appeals to me, but do you soak them in that case too? Full strength, that’s a lot of peroxide!
Terry,
You could try putting something inside the pots to decrease the amount of peroxide needed (So it would be the pot that needs cleaning with a slightly smaller pot inside, so that you would only need enough peroxide to fill the area between the two pots). If you don’t have a smaller pot that fits, you might be able to fashion one out of tin foil and just set some rocks in it for weight. You could also do the same thing backwards (put the pot that needs its outside cleaned inside a slightly larger pot).
Another alternative to soaking the outside of the pot could be to use a poultice. Fold a paper towel in half, soak it with the cleaning solution, then lay it on the side of the pot. Keep covering the outside of the pot with the soaked paper towels, then wrap the pot with plastic wrap to hold the paper towels in place and keep the moisture in.
I need to remove the encrusted remander of mineral residue on the inside of my African Violet pot without endangering any future plantings. Removed a lot using vinegar.
I would like answers to the question in the above comment section. Where do I find the answers? Thank you.
Meris,
All questions on this page have been answered. Good luck!