7 Organic Tomato Blight Spray Recipes [Step By Step]

Tomato blight is a disease caused by the fungus Phytophthora infestans. Farmers become perplexed by getting repeatedly attacked with many fungal infections. One of the worst diseases that can happen to a tomato garden is tomato blight. It can destroy your whole garden within weeks. 

Sounds horrible, right? But Don’t worry,

Every problem comes with a solution. You can fight against tomato blight disease by using copper fungicides, serenade garden fungicide, aspirin spray, our special compound tomato blight spray recipe.

In this article, I have briefly described the tomato blight spray recipes, identifying tomato blight, prevention methods, and many more.

 So let’s dive into deep-

Tomato Blight Treatment And Spray Recipes

1.Copper Fungicides

Copper Fungicide is a copper-based garden spray that prevents and controls a lot of diseases caused by fungus. As tomato blight is a fungus disease, experts highly suggest using copper-based fungicides.

Why should you use it?

This is very weather resistant and also sticks to the plant or on the surface layer of leaves once dried, providing long persisting control. Also very effective to prevent tomato blight.

How to prepare homemade copper spray fungicide?

  1. Take 1 gallon of water. 
  2. Add 2-4 tablespoons of copper fungicide.
  3. Mix them properly and take them into a sprayer.
  4. Spray throughout the whole plant.
  5. Use it in every 6-7 days interval as long as the blight gets cured.


  1. The best copper fungicide we have found is Southern Ag – Liquid Copper Fungicide.
  2. If you haven’t any sprayer then check out this long-lasting and ready to spray copper fungicide. Our pick- Bonide 775 Copper Fungicide Rtu Natural.

Some helpful instructions if needed-

  1. You should cover the plant surfaces entirely with the fungicide to prevent infection successfully.
  2. Sometimes you better use the highest specified rate of dose, if the plants are highly affected by the disease. However, this can change relying on temperature and rainfall.
  3. For general prevention purposes, use the normal rate of spray in normal situations.
  4. If the disease incidence and weather conditions fluctuate highly then you better consult with a professional in this field like Agricultural Extension Service.
  5. Use as a foliar spray on vegetables like tomatoes and also in ornamental plants, trees, shrubs, and conifers to control fungus disease.
  6. As a dormant spray and to get better results in case of tomato blight it can be used with insecticide oil    (like Horticultural Oil).

2.Serenade Garden fungicide

Serenade Garden is a vast spectrum, preventative bio-fungicide highly recommended for controlling fungus-based disease, specifically the blight.

It works against the blight (both early and late blight) on tomato plants very effectively as well as on all vegetables, flowers, fruits, and ornamental plants.

It also controls Bacillus subtilis, which can cause black mold, powdery mildew, rust, grey mold, scab, and some other infections.

Applying guide-

  1. Follow the instructions on the package and make a spray solution.
  2. Spray it on the whole plant.
  3. Repeat in every 7 days interval if needed.
  4. To get the best results, use it prior to foliar disease infection or as soon as you find the infection.


Here is the most effective Serenade garden fungicide to treat tomato blight-Serenade Garden AGRSER32 Disease Control Effective Organic Fungicide

Some helpful information-

  1. It’s very safe that you can spray up to the day of harvest.
  2. Certified organic fungicide by OMRI (Organic Materials Review Institute)

3.Compound Baking Soda Mixture

Baking Soda proceeds by creating an alkaline setting on the leaf and for this fungus cannot inhabit the surface of that leaf because they require a neutral pH (close to 7.0) to withstand and grow.

The spray of Baking soda and water will remake the pH of the leaf at around 8.0. This alteration of pH is sufficient to prevent, and kill all the blight spores!

Also, baking soda is very efficient and works well against tomato blight.

How to prepare a compound baking soda mixture?

You can prepare baking soda at home very easily using my method and measurement. Just follow these simple steps:-

  1. Take 1 gallon of water.
  2. Add 3 tablespoons of baking soda and mix them.
  3. Add 1 tablespoon of vegetable oil or cooking oil that is available.
  4. Add 2 drops of dish soap that will help emulsifying everything.
  5. Mix all of them properly and take into a sprayer
  6. Spray on the whole plant till you see it dipping.
  7. Spray with an interval of 3 weeks.


  1. You can buy ready to use baking soda for plants. Our pick- Frosch Natural Baking Soda Multi-Surface All Purpose Cleaner Spray.
  2. If you need ready to use horticultural oil then check out this MONTEREY  LG6294  Horticultural Oil.
  3. Never buy the wrong dish soap. Some of them contain dangerous chemicals that are harmful to plants. The best safe to use insecticidal soap we have found is Natria 706230A Insecticidal Soap Organic.

Some Helpful information-

  1. Begin with 3 tablespoons of baking soda, and apply once in 3 weeks.
  2. If the fungus is still growing then use 3 and a ½ or 4 Tablespoons.


Never spray this mixture under the full sun. The best option for you is to use it either in the morning or evening.

4.Compound Homemade Fungicide Mixture

This powerful compound fungicide is able to treat early blight,  late blight, fusarium, leaf mould, and many more diseases caused by fungus.

Specifically, I found it effective against tomato blight.

Wondering, how to prepare the fungus killing remedy?

  1. Take a bulb of garlic. 
  2. Add a tablespoon of canola oil.
  3. Add a tablespoon of hot peppers.
  4. Add a tablespoon of lemon juice.
  5. Mix these ingredients properly and steep for a night in a bottle.
  6. On the next day, strain the mixture through a sieve or cheese cloth whatever is available in order to remove the solid particles.
  7. Mix 4 tablespoons of these mixtures with one gallon of water.
  8. Spray both sides of the leaves and the whole plant.
  9. Try not to spray under full sun.


You can buy canola oil. Check out this Crisco Pure Canola Oil.

5.Aspirin Spray

This wonder medicine that has benefited people for centuries is also a marvel in the garden. I’ve found many amounts of aspirin in traditional fungicide spray.

However, after going through many trials and errors, I’ve found that this recipe provides me the best result.

So how to prepare the Aspirin solution?

  1. Take 1 aspirin and crush it into powder.
  2. Take 4 cups of water and mix them properly.
  3. Spray it on your plant every 2-3 weeks through the growing season. That will help the plant to prevent tomato blight effectively.

6.Some Specific Commercial Organic Tomato Blight Spray

Since blight is a very dangerous and destroying disease, researchers have prepared many effective solution packages.

Some of them are specifically made for tomato blight and other fungal diseases. All are very powerful and easy to use.


So far we have found these commercial organic tomato fungicides as best:-

  1. Garden Safe Brand Fungicide
  2. Bonide 811 Copper 4E Fungicide

7.Pruning Infected Parts

Before you are going to apply any of these methods or some other methods you have to prune the infected parts of the plant first. 

Because infected parts contain a lot of fungi. You let it be there then they will however affect your healthy plants again. So prune them as much as you can. In this case, use a pruning knife and a pot. 

The procedure will be-

  1. Cut a leave or stem,
  2. Shrink it into bleach-water.
  3. Put it into a big pot.
  4. After the pruning is complete, destroy all of the cuttings with fire.
  5. This will stop further infection.

To prepare bleach-water,

  1. Take one tablespoon of bleaching powder.
  2. Mix it with 2/3 gallons of water.


  1. You can buy bleaching powder. Our pick –Clairol Bw2 Powder Lightener.

Favorable Environmental Conditions for Tomato Blight

  1. The tomato blight pathogen, particularly fungus, is favored by cool, wet weather.
  2. Clouds help to preserve the spores from disclosure to UV radiation of the sun.
  3. Wet climates let the spores infect when they land on the plant’s leaves.
  4. Nights in the 50s or 60s and days in the 80s accompanied by heavy dew, fog, or rain are suitable for late blight disease.
  5. Under these circumstances, lesions may be seen on leaves within 3-5 days after infection, followed by white cottony growth soon thereafter.
  6. This white cottony development is an indication of extensive spore production.
  7. Sometimes spores are developed on tomato fruit when they are more naturally developed on leaves.
  8. Spores can scatter and spread rapidly by irrigation, rain, wind, equipment, rain, and can be hit into other fields within 6-10 miles or even more, thus starting up another cycle of infection.

10 Ways To Prevent Tomato Blight

In order to prevent losing your tomato plants by tomato blight, then it’s time to take some reasonable and easy steps to prevent it.

  1. Plants grown outdoor are more vulnerable to disease, so you can try growing tomatoes within a greenhouse
  2. You can choose blight-resistant varieties to grow. There are a lot of tomato variants available that are resistant to many diseases along with blight. Sus as ‘Losetto’, ‘Lizzano’.
  3. Blight easily spread with water-splash, winds, and extremely infectious in wet, warm weather. Make sure to stay out of this condition.
  4. Keeping tomatoes dry is a good way to prevent fungus infection. You can use an umbrella or transparent roof over a tomato garden bag or a polythene bag in order to keep the rain off them.
  5. Providing good ventilation is a necessary thing. Ensure that there is reasonable ventilation around the plants. Try keeping the sides of any lid open and try to avoid moisture growth. You can also thin out some old branches of bush species and also eliminate weeds to enable air to circulate freely.
  6. Try planting early to attempt for harvest before late blight strikes. However, try not to plant near potato fields that are sensitive to blight.
  7. Destroy blighted vegetation to reduce the possibilities of infection.
  8. Try not to leave potato tubers in the soil ground at harvest as they can harbor blight.
  9. Blighted foliage can be composted away from the plant garden because spores require a living host to withstand for more than a week or few.
  10. Try variants that rip earlier. Cherry tomatoes manage to be less likely to catch blight than others such as beefsteaks. That is because they ripen very early and are often harvested before the blight strikes.

How to Identify Tomato Blight?

Identifying Tomato Early Blight

Early blight symptoms can arise on the fruit, foliage, and stem at any phase of growth. Early blight is more usually detected in the outside garden, although seedlings in the greenhouse or indoor can also be affected by collar rot (also affected by species of Alternaria).


Lesions expand  as tiny, brownish-black spots on lower leaves of tomato that can further expand up to 1⁄2 inch in diameter with distinct concentric circles in the darkened region. The surroundings of those lesions are normally yellow in color and as the disease progresses, the entire leaf turns yellow.

In later stages,

Lesions also arise in the upper leaves and meanwhile, defoliation can happen in the lower portion of the plant abandoning the fruit susceptible to sunscald.

Fruit can be effected through the calyx around the stem branch and are vulnerable in the red or green phase. Lesions can increase until they cover the whole fruit and are commonly dark brown to black, sunken, and leathery with concentric circles.

Sometimes spores can be left on lesions on any part of the plant. For this always burn try to burn them.

Identifying Tomato Late Blight

The earlier symptoms of late blight on tomato are irregularly formed water-soaked lesions. It often appears with a lighter halo or ring surrounding the lesions. These lesions normally form on the younger, succulent leaves on the upper side of the plant canopy.


During increased humidity, white cottony growth may come to visible on the bottom of the leaf, where the sporangia develop. Spots become noticeable on both sides of the leaves.

As the disease progresses,

Lesions expand resulting in leaves to turn brown, shrivel, and finally die. Late blight is able to affect tomato fruit in all phases of growth.

Look alike Diseases

Since many fungal diseases can happen on the foliage of tomatoes it becomes difficult to identify them separately. For this, here I have comparatively described some of them to make identification easy.

  1. Septoria leaf spot creates tiny lesions with a tan or light grey center.
  2. Grey leaf spot also creates tiny and lighter brown lesions. But the difference is you would notice with early blight, and the middle of the grey leaf spot lesions is they tend to crack easily.
  3. Late blight creates lighter tan-colored lesions that normally have a light green circle. Late blight usually occurs all over the plant including new leaves, stems, and fruits.
  4. Early blight is primarily found on the lower leaves of the plant.
  5. Bacterial spots can also be confused with early blight at the first stage when the early blight lesions are young and small or when both of the characters are present.

However, the bacterial spot will be tinier (~1/16 inch), look like water-soaked on the bottom of the leaf, and the midst of the lesion can fall out.

  1. Some other varieties of Phytophthora, mainly Phytophthora nicotianae and Phytophthora capsici, can also result in lesions on a tomato plant and tomato fruit identical to those caused by late blight. 

However, these two varieties are soil-borne (as opposed to airborne) and generally only cause infection after the plants have been flooded or if the plant had been in touch with very wet soil.

Tomato Early Blight vs Late Blight

Early blight can be separated from late blight on tomato and also from other foliar fungal diseases by looking at where they occur on plants.

The main point is,

Lesions resulting from late blight can be seen everywhere on the plant, but are especially found on the new growth. On the other hand, early blight normally starts on the bottom side leaves and gradually moves up the plant.

One more thing to notice,

Lesions resulted in by late blight tend to be light brown or tan in color whereas lesions resulted in by early blight tend to be dark brown in color with concentric circles.

Can I Eat Fruit From a Blight Affected Tomato Plant?

Blight is not deadly or poisonous. According to the British Columbia Ministry of Agriculture, you should dip the fruit or part of the plant in a bleach solution before eating. I have described earlier in this article how to make a bleach solution. 

However, after the fruit has evolved into the leathery brownish color and rot as characteristic of blight,  you won’t like to eat that tomato. Because the flavor of the tomato will be horrible.

But as long as the fruit stays fresh, it will be good to eat.

Last Words

I have described every possible thing that came to my mind. Hopefully, you will be benefited from this article. If so, then you would like to look at my other articles also. We are continuously updating our content to provide the best guidelines you need.

If you have any query then feel free to interact with us using the comment section. If you are using a different method against tomato blight, then please let us know.

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