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How To Stop Tomato Blight! What To Do If Your Tomato Plants Have Blight

Is there any possible way to stop tomato blight once your plants start to show signs of having it? As mid-summer begins to settle in, that question finds its way into our inbox more than a few times each day!

There is nothing more frustrating for a gardener than to see their once healthy and beautiful tomato plants begin to show the first tell-tale signs of blight. It can start out with just a few small dark circles or spots that appear on a tomato plant’s lower leaves. And it only gets worse.

Before long, more and more spots begin to show up. As they grow in size, many of the dark spots also begin to form small circles within the spots, almost looking like some type of a crude archery target.

Tomato Blight signs
The first sign of tomato blight is usually a darkening of it’s lower leaves. The leaves can brown at the tips or have black or dark brown circles appear on the foliage.

From there, it’s all downhill. The plant slowly begins to fade away. The leaves turn brown or black and begin falling from the plant. Those that don’t fall off cling to their stems by a thread. Before long, the plant’s fruit begins to fail as well, and the entire plant begins to wither away and die.

And here is the really bad news – not only is the hope of a good harvest gone, but the health of future tomato plants that grow in the same soil can be jeopardized as well.

Can You Stop Tomato Blight?

So is it really possible to stop tomato blight once it occurs? The answer is a resounding “maybe”. But in order to have any chance at stopping the disease, you have to act swiftly.

One thing is for sure, without any action at all, blight will take out the infected plants. And most likely, any other tomato plants around it as well. And if you have other susceptible vegetable plants nearby such as potatoes or peppers, it can wipe them out too.

As you will see below, there are a few remedies that have a bit of success in dealing with a plant infected by blight. But more than anything else, it is first important to rid your plants of any infected limbs, foliage and fruit.

tomato blight
Left to progress on its own, blight will completely kill a tomato plant. Even worse, it will spread to other nearby plants, infecting them as well.

Then and only then, you give yourself at least half a fighting chance against the tomato killing disease. With that in mind, here is what to do to your tomato plants when they show the first signs of blight.

How To Stop Tomato Blight – The Best Ways To Fight Blight!

In the fight against bight, it’s important to know how the disease starts and spreads. Blight is caused by soil born spores that become airborne and then land on the foliage of plants.

Most often, the spores live in the soil below plants, where a hard rain or even a garden watering can splash them on to lower limbs. Spores can also be picked up by a strong wind or current as well. However they arrive, once on the plant, they begin to infect it quickly.

The best way to fight blight and win is with an aggressive approach. First and foremost, begin checking your tomato plants for blight early in the growing season. The earlier you see the first sign and take the appropriate action, the better chance of success.

Remove any suspicious foliage immediately. It is best to remove the entire stem or branch where you see the infection – even if it is only on a single leaf or two. Most likely, the disease has begun to spread further than the damage that is visible.

Clean Your Pruners!

We often talk about disinfecting your pruners or scissors between use. But with blight, you should be wiping down the blades of your pruners between every plant. The spores can easily spread from the blades of your shears right to the next plant you use them on.

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To disinfect, dip in a solution of bleach and water, or wipe or spray off with a disinfectant. This little process can stop the spread more than you know! Product Link: CleanSmart Disinfectant Spray

Any and all limbs should be discarded immediately. If you have a fire pit, you can burn them to kill the spores. If not, wrap up tightly in plastic and discard in your trash. Never place any blight or potentially blight infected material in a compost bin or pile.

Mulch & Prune Immediately – How To Stop Tomato Blight

If you have not done so already, now is also the time to mulch your soil heavily. A four to six inch layer of straw can help keep any additional spores from splashing up. In addition, this is also the time to prune up underneath your tomato plants.

By pruning up ten to twelve inches at minimum, you make it harder for spores to find their way onto the bottom leaves of the plant. Again, burn or discard any of the limbs. Also disinfect your pruners between each and every plant.

If your plants have grown together thickly, it is also a good idea to prune a bit out of the middle to allow for better air flow. When plants remain moist without circulation, the chance for blight to take hold increases.

how to stop tomato blight
The two best things you can do for your tomato plants is to prune and mulch. By keeping the limbs off the ground, spores are less likely to find a path to them.

Pruning can really help to keep your plants healthy for so many reasons – and it is a great practice to get in the habit of – whether you have blight issues or not. (See: How To Prune Tomato & Pepper Plants)

Homemade Baking Soda & Vegetable Oil Spray – How To Stop Tomato Blight

If your plants have been infected, there is a homemade spray you can apply to try to minimize damage and in some cases, stop the spread entirely. The solution is made from water, baking soda and vegetable oil. It can be applied directly to your plants as both a remedy and a deterrent.

To make, mix 1.5 tablespoons of baking soda and 1.5 tablespoons of pure vegetable oil into one (1) gallon of distilled or non-treated water. To use, apply with a clean pump or hand held sprayer, coating the leaves and stems of the plant.

The antibacterial qualities of the baking soda are thought to provide protection. The vegetable oil acts as a binding agent, helping the spray stick to the plants. For full effectiveness, reapply every week, or any time you have a rain that can wash it off.

Additional Methods To Help Your Tomato Plants – How To Stop Tomato Blight

There are a few additional precautions to take to help to keep your plants safe. When watering your plants, water low and slow at the base. Splashing water can easily splash spores up onto plants, or from plant to plant.

In addition, water only in the morning, as wet or moist plants overnight can be troublesome – both for spores, and for inviting mildew to the party too.

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Leaving infected plants in the ground will allow the spores even more opportunity to take hold. Once a tomato plant shows no signs of recovery, it is best to remove it entirely.

If a plant does become heavily infected, pick off any and all of the unripe tomatoes that show no signs of damage. These should still be able to ripen off the vine. Once a plant is infected, it will not ripen on the vine. In addition, leaving the plant can only serve to spread blight more.

Finally, take note of where your affected tomato plants grew. Make a note to not plant your tomatoes in that spot for at least three years. Doing so would only be setting your plants up for a yearly battle with blight.

Here is to trying to stop blight and save as much of your tomato crop as possible. Happy Gardening – Jim and Mary.

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