The worst diseases that impact tomatoes are often fungal diseases. They can be difficult to treat and difficult to get a hold on; this is especially true if the disease has set in and is at an advanced stage.
There are some good treatments that you can buy, but there is also a simple home treatment for fungal and wilt diseases in tomatoes. Baking soda!
This is a cheap and effective treatment that you can use for all types of blights and fungal diseases in tomatoes.
Jump to:
- Other Benefits of Baking Soda Spray for Tomatoes
- What Types of Diseases Can Baking Soda Treat?
- How Baking Soda Works to Prevent and Treat Tomato Fungal Diseases
- Simple Home Remedy for Tomato Blight & Fungal Diseases
- Cheap, Easy Homemade Baking Soda Spray for Tomatoes: The Recipe
- How to Apply Baking Soda Treatments to Tomatoes
- More is Not More -- Use Baking Soda Spray Judiciously
- Using Baking Soda as Disease Prevention
- Using Baking Soda as Disease Treatment
- Other Tips for Maximum Effectiveness:
Other Benefits of Baking Soda Spray for Tomatoes
Along with disease prevention and control, baking soda spray brings a few other benefits.
These include controlling some bad insects and parasites like slugs, ants, and aphids.
Baking soda can also make your tomatoes taste sweeter. So your work to control tomato diseases may make them the best tasting yet!
What Types of Diseases Can Baking Soda Treat?
If the disease has a fungal root, chances are baking soda will work for it. The more common tomato diseases that baking soda prevents and treats are
- Early blight
- Late blight
- Wilt
- Septoria leaf spot
- Other fungal diseases
- Downy Mildew
- Also deters or kills some insects, including slugs, ants, and aphids
For the most part, if the disease has a fungal base, or is one that proliferates in moist or humid conditions, it’s a good bet that this baking soda recipe can treat it.
How Baking Soda Works to Prevent and Treat Tomato Fungal Diseases
Baking soda works by raising the pH on the surface of the tomato plant. Since fungi need acidic conditions to colonize, the slightly increased pH creates an environment in which they have difficulty taking hold.
To be clear, baking soda does not truly “kill” fungal spores, but it does create an environment that is difficult for them to live in. When the spores cannot reproduce in high numbers, the disease is controlled. Even if a small infection remains, it won’t be enough to do serious damage to your tomato plants or to the fruit.
Because you can only use baking soda in low concentrations (so you don’t damage your tomatoes), severe infestations are sometimes difficult to control with baking soda alone. There are options for using an additional natural anti-fungal agent in the recipe (see below).
Simple Home Remedy for Tomato Blight & Fungal Diseases
Cheap, Easy Homemade Baking Soda Spray for Tomatoes: The Recipe
It is important to only mix this spray in the recommended proportions to avoid burning or damaging your tomato plants.
To make the spray, mix together:
- 1 gallon of water
- 1 tablespoon baking soda
- 1 tablespoon vegetable oil (can use Neem oil or horticultural oil)
- 1 tablespoon dish soap (or insecticidal soap)
Mix to combine, then apply with a spray bottle or a garden sprayer, as instructed below.
The water will dilute and carry the baking soda, and it will give you enough volume to create an effective spray.
The baking soda is considered the “active ingredient” that works to deny the fungal spores the environment they need to grow.
The dish soap and vegetable oil are largely carrying agents that help the baking soda adhere to the plant so it can stay on long enough to work. They also have some protective and insecticidal properties, but must be used in moderation (and in the amounts given in the recipe) to prevent damage to the plants.
How to Apply Baking Soda Treatments to Tomatoes
This baking soda tomato spray recipe is applied as a plant and foliar spray.
- Apply with a garden sprayer (easiest and most recommended, especially if you have a number of plants to treat)
- Or mix and pour into a handheld spray bottle to apply
- Spray all the leaves, top and bottom
- Spray the plants’ stems
- Spray just until wetted
- Allow to dry on the plant
More is Not More -- Use Baking Soda Spray Judiciously
It is important not to overuse baking soda spray. Overuse can block light, dehydrate, or damage your tomato plants. Significant overuse of baking soda could potentially change the soil pH, too, and that can cause other problems for your tomato plants.
In the low concentration in the recipe, and used according to an acceptable application schedule, baking soda spray is quite safe, but you should not mix the spray in more concentrated solutions.
Do not apply baking soda spray more often than is recommended.
Using Baking Soda as Disease Prevention
Blight and fungal diseases are almost guaranteed for many of us. If you live in a humid climate, it can be very difficult to avoid blight and fungal disease. In that case, prevention can be very helpful.
Baking soda spray works well as a preventive as well as a treatment for these types of diseases in tomatoes.
It would be especially worth using a preventive maintenance treatment if you are experiencing a very rainy, humid year.
As a preventative measure, use baking soda spray this way:
- Apply once a week, or about every seven to 10 days
- Spray the entire plant, stems, and leaves
- Spray just until wet
- If you get a heavy rain that washes the baking soda off within the first four or five days, you can reapply, but then don’t apply again before another seven days is up
Using Baking Soda as Disease Treatment
This spray also works as a treatment for fungal diseases and blight. The sooner you start treating with the spray, the more effective it will be.
As a measure to treat wilt, mild, early, or late blight, or fungal disease, do the following:
- Apply at the first sign of disease
- Spray the entire plant, including stems, the tops of leaves, and the bottoms of leaves
- Spray until wet and just dripping
- Repeat the treatment every seven to 10 days
- If heavy rains occur, you can reapply the baking soda after the rains stop (rain will wash the baking soda away)
- Reset the 7 to 10 day count if you have to reapply, and don’t apply the next treatment too early
- Do not overapply baking soda
- If the baking soda alone is not enough to control the disease to a manageable level, combine it with another type of treatment that targets the disease or pest in question
- Baking soda spray for infected plants will largely control the disease, but will probably not kill every last spore, so continue the treatment for the rest of the growing season
Other Tips for Maximum Effectiveness:
Good preparation, planting, care, and maintenance will go a long way in preventing fungal diseases and helping plants fight them off if they are exposed. That, combined with this spray, can go a long way to successful growth and harvesting.
Following are some tips to pair your baking soda spray with for happier, healthier tomatoes.
- Support plant health by providing adequate nutrients and water -- healthy tomatoes are less prone to disease to begin with
- Don’t crowd tomatoes in the garden bed
- Space properly between plants
- Space properly between rows
- Maintaining good air circulation is key to preventing and controlling fungal diseases in tomatoes
- Water from the bottom
- Avoid wetting stems and leaves when watering
- Avoid overwatering with sprinklers if possible
- If you must use a sprinkler, do it early in the day to give the plants time to dry off
- Water only as necessary
- Standing wetness on tomato plants invites blight and disease
- Consider combining baking soda treatment with another eco-friendly option, like Neem oil or Copper Sulfate
- A second-line treatment may be in order if baking soda alone is not controlling blight or disease
- If you prefer, instead of vegetable oil in the recipe, you can use Neem oil, which will provide even better defense against fungus, mildew, wilt, and insects (Neem is a natural insecticide, but avoid spraying when bees and pollinators are active)
Baking soda has other good uses for tomatoes and the vegetable garden. Check out these great ways to use baking soda in the garden.
