Is Baking Soda Good for Tomatoes?
There are plenty of garden myths out there, and using half-baked homemade formulations are part of that. But some of these remedies do have their benefits when used correctly. Experienced gardener Sarah Jay discusses how baking soda could be a viable option.
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It’s easy to get into the idea of using household products in the garden, especially if you’re growing organically. Baking soda is used to limit powdery mildew, as a general fungicide, and to sweeten tomatoes. However, not all of these uses have been proven effective.
While it’s tempting to want to save money and time following the most recent trends (and even the longstanding ones), check the science first! Find a study or a reliable scientific outlet that provides evidence to back up the claims, and you’re set. It’s nice when your tomatoes benefit from a home remedy with proven uses.
However, before you get out your sodium bicarbonate, let’s run through the details of what works and what doesn’t for your tomatoes. There are some ways you can use baking soda, and others that really don’t have any proven effectiveness.
The Short Answer
When it comes to baking soda, tomatoes do benefit from a solution for certain purposes. Adding baking soda to soil isn’t a good idea, but using it for fighting fungi on your vines can help. Proper applications are important, so make sure you’re following informed instructions before you start spraying.
The Long Answer
It’s good to know what you can use it for before you get out your baking soda. Tomatoes do experience benefits from baking soda sprays, but they don’t actually get sweeter if you apply it to the soil. Here are the right and wrong ways to use it!
Can It Sweeten Tomatoes?
Unfortunately, when you’re using baking soda, tomatoes do not get sweeter. Wouldn’t that be awesome, though, if all you had to do was sprinkle some baking soda around your tomatoes every once in a while, and they’d take on a more delicious flavor? Sadly, it’s just not the case.
The truth is that variety, genetics, and overall plant health are the greatest determinants of flavor, rather than supplemental nutrients. If you want a sweet tomato, look for sweet cultivars. For a sweet cherry, choose the yellow variety Sun Gold. ‘Pineapple Pole’ tomatoes are notably sweet with a low acid profile. Mountain Merit is a good determinate variety that has a sugary reputation.
Start by selecting a low-acid variety that has the sweetness you want to grow a nice, juicy, and sweet tomato, rather than relying on additives. So, when it comes to baking soda, tomatoes do not get sweeter when you add it to the soil.
Baking Soda As Fungal Control
You may have read about baking soda as an effective treatment for powdery mildew. It’s also an effective treatment for fungal issues with tomatoes. Three fungal diseases are common among tomatoes: early blight, late blight, and septoria leaf spot. It is possible to prevent and treat these diseases with a baking soda solution that includes a binder (some kind of oil) and lots of water.
Sodium bicarbonate (the compound we call baking soda) is particularly effective against septoria leaf spot disease. The mechanism behind this control is not in fungicidal capabilities, but in baking soda’s ability to limit fungal growth. By increasing the pH of the plant’s surface, spores can’t reproduce, as they typically would in more acidic conditions.
This makes it an effective treatment and preventative if you’re working with a particularly disease-prone variety, or in an area where diseases are likely to crop up. However, for your tomatoes, baking soda is more effective post-harvest, on fruit in storage, rather than for the plant itself. We’ll get into those particulars in a moment.
How To Apply
To start, create a solution with the proper ratio of water, baking soda, and binder – or some kind of dormant oil. Vegetable oil works, as well as any kind of sticker spreader. Keep your baking soda at one tablespoon, and your binder at one teaspoon. Then dilute them in at least one gallon of water. A couple of drops of castile soap help, but it’s not wholly necessary.
To treat fungal infections, first identify your disease. Early and late blights arrive either early in the season or late in the season, respectively. Check your leaves regularly, as this is where the infections start. They create lesions on leaves that spread and form yellow halos. Septoria leaf spot typically presents early in cool seasons, forming small, brown, speckled lesions with light-colored inner parts.
To treat these diseases, remove the damaged leaves, and then test the solution on a leaf before applying it to the entire plant. If there is no discoloration or damage to the leaf as a result of your spray, lightly spray the rest of the plant. As prevention, a light spray at the beginning of the season when your tomato plants are mature is good. But always test a leaf first!
Potential Drawbacks
Because we are dealing with sodiums, it’s detrimental to do multiple applications of baking soda. Tomatoes forced to deal with many sprays over the course of a season can take on damage.
Compounding saline on leaf and stem tissue causes huge problems for tomatoes, which are vigorous, but supple and sensitive. This turns your fungal control into an herbicide. Further, it’s not as effective for stems, where the sprayed solution can run off easily.
Using this solution is more of a once or twice in the entire season kind of thing. Keep it minimal, trellis your tomatoes properly, and avoid overspraying, which can devastate a crop. If you see any mottling or yellowing, it’s likely the plant has experienced chlorosis as a result of saline toxicity.
Final Thoughts
As you can see, this is one of those gardening tips that teeters the line between tip and myth. Baking soda is effective, but when used improperly, it’s too effective. Start by cultivating your tomatoes properly, watering them at the base, and providing healthy soil and fertility.
If all this fails, one or two applications of a light baking soda solution can be effective. But always test first to ensure the plant is safe from harm. Use it to keep fungal rots off fruit and to store your tomatoes longer. So when it comes to baking soda, tomatoes can benefit! Just be careful when you use it.
