Smart Ways to Use Baking Soda in the Garden (What Works and What Doesn’t)
Have you ever tried using baking soda in the garden? Baking soda can be used to remove rust from garden tools, clean containers, absorb odors from garden bins, and test your soil pH!
When used properly, it can also be effective as a fungal spray and weed killer for concrete cracks and gravel driveways.
While baking soda is a great cleaner, it contains a high amount of sodium, which can be harmful to plants and soil when used improperly. Keep reading for a list of 9 ways to use baking soda safely in your garden.
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Safe ways to use baking soda in the garden
Baking soda is an eco-friendly, non-toxic cleaning option for garden items. You can use baking soda for cleaning, sanitizing, and deodorizing the following items.
Clean rusty garden tools
Garden tools can develop rust over time, especially when exposed to moisture. Baking soda’s mild abrasive properties make it effective for removing surface rust without damaging the metal.
- Mix equal parts baking soda and water to form a thick paste.
- Apply the paste to the rusty areas of the tool.
- Let it sit for 30–60 minutes to loosen the rust.
- Scrub gently with a wire brush or scouring pad.
- Rinse thoroughly and dry completely to prevent future rust.
Deodorize garden bins
Garden refuse bins can develop strong odors, especially when they contain moist plant material such as weeds, grass clippings, or leaves. Baking soda helps to absorb moisture and neutralize odors.
- After collection day, sprinkle a generous layer of baking soda in the bottom of the empty, dry bin.
- For a more thorough cleaning, scrub the interior with a mixture of baking soda and water, then rinse and dry.
Deep clean clay pots
Even after cleaning, clay pots can still have stubborn salt deposits and dirt residue. Baking soda acts as a non-toxic abrasive that helps to remove these stains without damaging the pot’s porous surface.
- Remove any leftover soil from the pots with a brush.
- Clean them thoroughly with 1 cup of vinegar and 3 cups of water.
- Make a paste of baking soda and water with the consistency of hand lotion.
- Rub the paste onto the salt mark or stains, and leave it in place for about 20 minutes.
- Rinse thoroughly and allow the pots to dry completely before using.
Clean & sanitize bird baths
Bird baths need regular cleaning to keep birds healthy and prevent algae buildup. Baking soda is a safe, non-toxic cleaner that works well for routine maintenance and lightly soiled bird baths.
- Dump out any standing water and remove loose debris.
- Sprinkle baking soda directly onto the surface of the bird bath.
- Use a scrub brush and warm water to clean all areas.
- Rinse several times with clean water before refilling with fresh water.
Note: For another gentle cleaning option, see my article on cleaning a bird bath using Alka-Seltzer tablets and copper, which shows before-and-after results. Heavily soiled bird baths may require deeper sanitizing, such as the bleach cleaning method described here.
Sanitize garden work surfaces
Potting benches can harbor soil-borne diseases that transfer from one plant to another. Regular cleaning helps prevent this, and baking soda provides a gentle, effective way to sanitize surfaces naturally.
- Mix 4 tablespoons of baking soda into 1 quart of warm water.
- Use the solution to scrub the potting bench thoroughly, paying attention to corners and crevices.
- Rinse the bench with cold water and let it dry completely before using it again.
This technique also works for garden benches or tables that you work on with potting soil and plants.
Is baking soda safe for plants?
Baking soda has legitimate uses in the garden, but improper application can damage plants and soil because it contains sodium. Keep these key points in mind:
- Baking soda does not distinguish between weeds and your plants.
- Its sodium content can harm plants if too much is applied.
- Repeated use can alter soil chemistry over time.
How to use baking soda for plants (what works and what to avoid)
Looking for some more creative ways to use baking soda in the garden?
Below are the four best ways to use baking soda for plants. Each method has instructions, an explanation of how it works, and any potential problems you may encounter.
Fungicidal spray for powdery mildew
Gardens with high humidity are prone to developing powdery mildew. You can use baking soda to create a preventative fungicidal spray for your plants.
Baking soda powdery mildew fungicide recipe:
- Mix 1 tablespoon each of baking soda, vegetable oil, and dishwashing liquid with 1 gallon of water.
- Pour the solution into a spray bottle, and apply it to plants weekly.
How it works:
- The solution creates an alkaline surface on leaves that slows fungal growth.
- It acts as a preventative fungicide, helping slow the spread of spores before the disease takes hold.
Potential problems:
- Frequent use over time can raise soil sodium levels, potentially slowing plant growth.
- It does not kill existing fungus, so it works best as a preventative treatment.
- It is water-soluble and requires regular reapplication for continued protection.
Baking soda fungicide is most effective when powdery mildew is just starting to develop. For plants with a severe infection, or if you want consistent results without risking sodium buildup, I recommend a garden-safe fungicide.
Fungal spray for tomato plants
When used properly, baking soda sprays can help prevent and manage fungal diseases on tomato plants (such as early blight, late blight, and septoria leaf spot)
Baking soda fungicide recipe:
- Add 1 tablespoon of baking soda, 1 teaspoon of vegetable oil, and 1 teaspoon of Castile soap to 1 gallon of water.
- Pour the solution into a bottle and use it to spray your tomato plants.
- This fungal spray is based on a recipe from the Department of Agriculture.
How it works:
- The baking soda fungicide spray changes the pH level of the leaf surface of tomato plants, making them more alkaline.
- This helps to prevent fungi like early blight from developing.
- Caution: Test this on one or two leaves first and wait 48 hours before you spray the entire plant.
Potential problems:
- Over-application can cause a buildup of sodium in the soil.
- It isn’t recommended for severe infections; it’s only useful as a preventative.
- The solution is water-soluble, so it needs to be applied frequently to be effective.
Note: If you are concerned about sodium buildup in the soil, Neem oil is an organic alternative.
Baking soda soil test
Soil pH reflects the amount of nutrients in soil that are available to plants. If your soil pH is off, plants can’t absorb nutrients correctly. A vinegar and baking soda soil test will give you a general test of your soil pH.
Baking soda soil test directions:
- Take a soil sample about 6 inches below the soil level.
- Place one teaspoon of soil into each of two containers.
- Add ½ cup of vinegar to one container. If the soil fizzes, you have alkaline soil, with a pH of between 7 and 8.
- If no fizzing happens, add distilled water to the second container until the soil is muddy.
- Add ½ cup of baking soda to this container. If the soil fizzes, you have acidic soil with a pH of between 5 and 6.
- If your soil does not react in either cup, you have neutral soil with a pH of 6.
- Test source: Washington State University.
How it works:
- Vinegar is acidic, and baking soda is alkaline. When these products react with soil, they can create bubbles.
- Bubbling with vinegar indicates acidic soil, and bubbling with baking soda indicates alkaline soil.
- These bubbles indicate a range of soil pH without the need for testing kits.
Potential problems:
- This test gives only a range of soil pH, but not a specific pH value.
- Some reputable reports indicate that the test is unreliable.
- For an accurate test that tells your exact soil pH, contact your State Department of Agriculture. Many state departments will test your soil for free.
Baking soda weed killer
You can use baking soda as a natural herbicide for weeds in concrete cracks and gravel driveways, but it must be used carefully.
How to do it:
- Wet the weeds first or apply the baking powder after a rain so that it sticks to the weeds.
- Apply a thick layer directly on the weeds you want to kill.
- Only choose weeds in cracks or in gravel driveways.
- Avoid using near garden beds and lawns.
How it works:
- Baking soda’s high sodium content dehydrates weeds and causes moisture loss, which kills them.
Potential problems:
- Baking soda is non-selective, meaning that it will also kill any plant it touches.
- It may not kill weeds with deep taproots.
- It is not permanent since it does not have a residual effect, and may require repeated applications.
- Excessive use may increase soil salinity and affect soil pH.
Common questions about using baking soda in the garden
Do you have more questions about using baking soda for plants in your garden? Check out the FAQs below.
Will baking soda make tomatoes sweeter?
No. Baking soda does not make tomatoes sweeter. Adding baking soda to soil or water can actually alter soil chemistry and may stress plants if overused. The sweetness in tomatoes depends upon variety, sunlight, water, and proper ripening – not the use of baking soda.
Does baking soda kill weeds in the garden?
Baking soda can kill weeds only when applied directly in cracks or on hard surfaces. However, it is non-selective and can harm nearby plants if sprinkled on soil or grass. Use it sparingly on driveways or patios, and avoid garden beds.
Does baking soda cure rose black spot?
No. Baking soda is not a cure for rose black spot (Diplocarpon rosae). It will not eliminate an existing infection. For an active infection, using a garden-safe fungicide and practicing good garden hygiene is more effective.
Can baking soda be used to repel garden pests?
Baking soda is not a reliable insect repellent. It may deter certain pests, such as ants or slugs, when applied directly in small areas, but it is not a reliable pest control method for your garden. Use targeted, safe pest control methods instead.
Can baking soda be used to make fertilizer?
No, baking soda does not provide the nutrients plants need to grow. While small amounts won’t harm most soils, it should not be relied on as a fertilizer. Stick with compost, organic amendments, or all-purpose fertilizers for healthy growth.
Does baking soda remove odors from a compost pile?
No, baking soda does not remove odors from a compost pile. Keep your compost pile’s odor low by using the proper amount of browns and greens. Additionally, baking soda’s high alkaline and sodium content kills essential microorganisms, slowing down decomposition.
Can you clean the leaves of indoor plants with baking soda?
Baking soda is not recommended for regular leaf cleaning. It can leave a residue on the leaves, which may block sunlight and reduce photosynthesis. For safe cleaning, gently wipe leaves with a damp cloth or use a mild, plant-safe leaf cleaner.
Does baking soda help cut flowers last longer in a vase?
No. Adding baking soda to flower water does not extend bloom life. Flower food packets and other natural methods are much more effective. Read how I tested these methods in my guide to cut flower care.
Printable of baking soda in the garden uses
You can print this list of uses for baking soda for plants as a high-resolution JPG or PDF by using the links below.
Printing instructions:
- Choose portrait orientation and “fit to page” on your printer settings for a full page printout.
- You can also print this free printable featuring how to use baking soda in the garden in a slightly smaller size from the project card at the bottom of this page. Just scroll down and press “print”.
More help for common vegetable garden problems
If baking soda isn’t the solution you were hoping for, don’t worry. These guides will help you diagnose common garden problems and choose treatments that actually work.
- 🌿 Why Do My Tomato Plants Have Black Spots? Learn what causes leaf spots on tomatoes and proven ways to treat them.
- 🥒 Why Are My Cucumbers Turning Yellow? From watering issues to nutrient deficiencies, here’s how to pinpoint the real cause.
- 🐛 Tips for Dealing With Invasive Pests – Learn how to identify harmful yard pests and control them using guidance developed in partnership with the USDA.
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Admin note: This article on how to use baking soda in the garden first appeared on the blog in June 2013. This post has been updated with new photos, a slideshow video, and a printable answering the question What is baking soda used for?
Baking Soda in the Garden – Safe Uses, Precautions & What to Avoid (Printable Guide)
Download this printable guide to see which baking soda uses are safe in the garden, which require precautions, and which should be avoided entirely.
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Notes
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Great ideas
Hi Carol, thank you for your baking soda tips I’m going to try this this evening. I appreciate natural ways to get rid of garden pest. I too love gardening both flowers and vegetables. Again thanks Johnnie M.
My pleasure Johnnie. Glad you found the article useful. Carol
I tryed it and it killed my plants made the leaves turn black
I listed many ways to use baking soda in the garden. Which one did you have a problem with? Carol
Is the use of dish washing soap in controlling powdery mildew acceptable in organic farming?
I have read the thinking goes both ways. Some say yes and others say no. You can buy commercial insecticidal soap (much more effective and safer than dish detergent), Neem oil, vegetable based horticultural oils, and several other commercial products that are deemed appropriate for organic gardeners. Carol
I like your sugestions.
Thanks Ellen!
Carol
Each year my tomato plants do rather well except the fruit has black rot on the bottom of the tomato’s, I tried the commercial grade sold at lowes for this but still have it, any ideas for this year???
Hi Robert. It sounds like blossom end rot.
Keep the soil’s pH at 6.0 to 6.5.
Use mulches to conserve moisture. Mulches conserve soil moisture and reduce incidence of blossom-end rot.
Give your plants plenty of water. Tomato plants need about 1.5 inches of water a week during fruiting and more if it is very hot where you live.
Some varieties of tomatoes tend to be more sensitive to conditions that cause blossom-end rot. Try growing several varieties and keep notes as to their performance.
Carol
When planting tomatoes, try putting crushed egg shells in the hole. The calcium will help to prevent blossom end rot.
Thanks for the tip! Carol
I learned on youtube to ensure no blossom end rot, you HAVE to add plenty of fish bone meal *calcium* nitrate granuals to your soil (which I scored on ebay for around $15 big bag) they cannot get enough calcium so if you add that no end rot- I also use crushed diff B, D and C vitamins from dollar store to the dirt and to my watering can, another trick I got from bogs
Thanks for the tips Brandy. Carol
it is a calcium deficiency in the soil.
Thanks for the info Terry. Carol
I’ve had problems with blossom end rot on tomatoes, there are two ways to combat it, as Blossom End Rot on tomatoes is usually caused by a Calcium Deficiancy in my case.
First, by dolomite as it usually will correct the problem.
Second, you can by a Calcium Spray at any lowes that will correct the problem.
i used blood meal found at lowes to combat the blossom end rot. worked amazingly
thanks Annette. The last time I asked about blood meal in Lowe’s, they had no idea what I was talking about. Perhaps my store stocks it now. Carol
For blossom end rot….mix cup of pelletised lime in 1 gal water. Poor in soil. About 2 cups per plant. Do this every 14 days. Calcium and magnesium rich .
Thanks for the tips Johnny. Appreciate it. Carol
Some fantastic ideas here, my favourite being the ‘sweeten your tomatoes’ I never knew it was possible to use baking soda in such a versatile way.
I’m trying to find as many ways to save water as I can (living in California) and I wondered about using bath water to water my plants. My concern is that my bath water contains baking soda, Epsom salt and magnesium chloride (due to the draught the only time I takes baths instead of showers is for health/detox purposes). Will these ingredients harm my plants? I have a variety of potted & in-ground flowers, tomatoes, veggies, etc. Thanks so much!
Hi Elysia. I’ve never used bath water (also called gray water by gardeners) but most of my research says that it is not harmful. Epsom salt is actually beneficial and baking soda can do a bit of good and normally does not harm them. Magnesium chloride is the only one I am not sure about. Epsom salt contains magnesium sulfate which is beneficial, but not sure on the magnesium chloride.
Carol
If you put a new unused disposable diaper in the bottom of your pots it will help hold the water a lot longer than not using one. You can also use disposable pads used for bladder leakage. The diaper will cover a larger area. I find in Phx AZ that the diaper in a 5 gal pot keeps the soil moist from 3-5 days when normally I would have to water every day to day & a half. They will last a season then you’ll need to change your plants diaper again.
Does it make the pot heavy? Carol
Baking soda also works wonders for cleaning terra cotta pots and garden decor I actually just went through and cleaned some of mine today.
Thanks for the tip Megan. I will try it on mine. Carol
thanks ;i’d try to my plants tomatoes,in the weeds around it
baking soda.
will baking soda work on squash plants? our butternut squash leaves get what looks like white mold & then the plant dies.
Hi Kathy, The methods will work for most plants, but what you have described sounds as though you may have squash bugs. This article describes the effect they have on plants. http://thegardeningcook.com/?s=squash+bugs
Carol
Very beneficial.
Hi. I love your tips on baking soda but you didn’t tell us how often to use the baking soda
to sweeten our tomatoes. Just once ?
Hi Jacque. It is good to test on one plant just to make sure the soil is not already acidic, but generally once when the tomatoes are about 1 inch in size and again when they are about half grown.
Carol
Thanks for the tip! Carol
My pleasure Dyah. Glad you found the tip useful. Carol
There’s lots of information on You Tube about putting 3 or 4 inches of shredded woodchips on the garden soil. It keeps it moist and you won’t need to water much. The wood makes the soil healthier.
You will need to add more every year. Happy gardening……….
Hi Lucille. Thanks for the tip. I do use mulch on all my garden soil and it really does help with moisture.
Carol
I put about 1/2 cup of wood ashes in hole before planting tomatoes, tomatoe plants are healthier & tomatoes have a sharp tomato taste.
Hi Meg. I don’t have a wood burning fireplace but have heard that wood ash is good for plants. Glad to hear it works well for you. Thanks for sharing the tip. Carol
How many trusses of tomatoes,would you recommend ,prior to nipping the top off? And is it a good idea to trim off bottom leaves up to first formed truss?I read somewhere a T Plant only needs say 6 leaves to maximize quantity of fruit? Is this so? Chris.
Hi Chris. If you nip the top, all of the energy will go to the tomatoes that are on the plant and no new ones will form. I always trim off the lowest leaves, since it makes it easier to water at the roots of they are clipped off. Carol
Mix baking soda with water and pour over unwanted mushrooms in your lawn to get rid of them! Works for me!
Hi Ted. Thanks for sharing the great tip. I had not thought of doing that. Carol
Carol, with the baking soda ,ammonia,and epsom salt, with one gallon of water, do I pour it on the roots of the roses, or spray it on the leaves .
Thank you for all your great hints..
Mary.
Hi Mary, I would put it into a spray bottle and spray on the roses.
Carol
I wish I found this page earlier in the year. We had an awful time with fungal issues with tons of rain this year. Thanks for the tips and will try them all. Thank goodness for Pinterest or I wouldn’t have found you. 🙂
Hi Liz. Welcome to my site. I hope that you enjoy looking around. Carol
Enjoyed your site
Hi Sharron. Welcome! Glad you are enjoying the site. Carol
Curious how baking soda can simultaneously be GOOD for garden plants and BAD for “weeds”…some of my “weeds” are edibles that I’d worry about killing in my zeal to do good…
Is is all in where you place it and how much, I think.
I have tiny little ants in my soil . The are so tiny and look red to me.. I sprinkled baking soda over my soil because I read if they are red they will kill my plants ..
Hi Lenore. Did the ants die or go away? Carol
The ant will take the baking soda into the nest where they and other ants will eat it and then explode. Not such a nice death but I don’t know if ants feel pain.
Wow, I’ve found a lot of useful tips. I like easy, inexpensive ways to enhance plants!
Carol also.
HI Carol. I’m glad you found the article useful! Carol
Hi Carol,
I make a mistake by put one tablespoon of baking soda into my cucumber plant’s soil. within few days, all the small cucumber and all the flower that ready to become baby cucumber turn dry and dead! I was very shock and sad. Is there anyway that I can still rescue my plants? The plant is too big to transfer to different pot. I have it in the big pot and the vine go all over my grapes. Thanks. I am waiting for your answer.
Lisa
It is hard to rescue vegetables that have been damaged this way. I would try cutting off the damaged areas and giving it a good watering and then watch to see if new growth appears.
Great ideas!! Also a good plant starter, or if you say, cut off a piece of a plant to put in water to root, either way… add a little peroxide to the water. Helps plants with root growth
Thanks for the tip Barbee. I’ll try it. I have some rooting right now. Carol
My lemon tree was having so much flowers and also got many buds but then suddenly all buds got black and no lemon at all
What was the reason
Pls advise..
Hi Sunita. Black rot, also known as alternaria fruit rotis is a fungal disease that affects citrus plants including lemon plants. . It is typically caused by the fungal pathogen, Alternaria alternata. Black rot develops on both the fruit and leaves during wet conditions. There are chemicals that will treat it such as imazalil or 2,4-D. I have not tried either of them. Carol
Just so you know you spelled bushes wrong you put buses I am not trying to get you called out I just wanted you to know
Thanks for taking the time to let me know. I appreciate it very much. I have revised the post so that the spelling is correct! Carol
You are welcome
Can I remove leaf weeds from my Curry leaves plantation (40 days siblings) using Baking soda? Pl oblige.
Proportion of usage..
I have never grown curry leaves so I don’t know how easily they are affected by weed killers, but I would not use any weed killers near seedlings. They are very susceptible to problems until the plant is well developed. Carol
I am highly impressed of what baking soda can do for me especially my garden. I will be more than happy to receive such writeup from you per my email.
Thanks
A.K.
I’m confused.So baking soda is beneficial to plants but it also could be use as a weed killer?What are the Mix ratio per gal?I Really do want to try this in the garden.Thanks
What can be good in one instance can hurt plants when used in too much concentrate. Since there are so many uses for the product, there is no way to give a blanket formula. It depends on why you are using it. However the article that I have written where you commented does have some formulas for many of the instances.
How much baking soda should you mix in a quart hose-end sprayer. The water from the hose dilutes the solution in the sprayer. Anyone have suggestions?
I have not tried this so I can’t make a guess.
I use 1/4 teaspoon of baking soda mixed into a 1/2 cup of warm water to treat indigestion and re-flux. Being alkaline it lowers the acidity and increases the alkalinity in the stomach.
Hi Carol, Your gardening tips are great, thanks! I have a pear tree that I really love. Well, it developed pear rust on its leaves and now the tree looks like it is dying. The top branches are bare all the time. Will putting baking soda around the trunk of the tree help at all? I called an arborist for help and he wanted hundreds of dollars to come to take a look at my tree. Thank you for any advice you can give me. Peggy
HI Peggy. You will have better luck with someone locally. I don’t diagnose any plants without being able to see the plant in person.
Is baking soda mixture like added with dishwashing liquid and vegie oil still favorable to add a pinch of ammonium sulphate..
well explanation no comments
I made a mixture for my plant as follows.
Copper sulphate 30 GM’s
Baking soda 20 GM’s
Prophenophos 50 %ec
Shampoo 18ml
All this together in 20litre and sprayed on my lemon trees after 1day lot of leaves are falling.
Pls help to quit from this problem
my lawn is totally full of crabgrass, how can i eliminate it without totally destroying a massive lawn, please,
Hi Anne. There are chemical that will target Crabgrass (Scott’s Spot Weed Control is one) but if the lawn is full of it, digging it up is the best solution.