Skip to Content

Fighting Tomato Blight – 3 Keys To Keep Tomato Plants Healthy

Tomato blight. Two words that strike fear into backyard tomato growers everywhere!

Tomato blight is a fungal condition that can devastate and destroy otherwise healthy tomato plants. It is spread through spores, and can easily wipe out an entire crop.

There are actually three distinct types of tomato blight. Early blight, Leaf spot blight, and Late blight.

Of the three, Leaf spot blight is by far the most common to the home gardener. It begins to appear in late June to early July, with the lower leaves turning black and rotting away.

Leaf spot will steadily begin to destroy all of the foliage of the plant, usually within 30 days of first appearing.

Early tomato blight will appear after the tomato plants have set fruit. This blight will also show in damaged leaves, but also with dark spot appearing on the tomatoes themselves.

It can completely rot out the fruit as it tries to ripen on the vine.

Late blight starts as a small light-colored spots on the foliage of plants. It quickly progresses until the stems, leaves and tomatoes turn black.

Late blight is spurred on by cool, damp temperatures. It tends to be more of an issue in cooler climates, or in growing seasons that are extremely wet and rainy.

The bad news is that once any of the above tomato blight symptoms have arrived, it is usually too late to help. Although you can remove damaged leaves and fruit as soon as you see them, blight usually will win in the end.

The real key is in prevention. There are actually quite a few things you can do that can help you avoid tomato blight. And you might be surprised how easy they are!

Fighting Tomato Blight – 3 Major Keys

Crop Rotation / Planting In A New Space

The number one way to keep tomato blight and disease from your tomato plants is by rotating your crops.

Growing tomatoes in the same soil or garden space every year is like opening the door to blight. Tomatoes are one of the most susceptible vegetable plants when it comes to soil-borne disease.

By planting continually in the same location, soil can become infected with spores. And every year you plant, they have an easy ride to killing off your new crop.

Rotate tomatoes to a new location or soil space each year for a minimum of 4 years. If you are growing tomatoes in containers, replace the soil each season with new potting soil.

Not only does this help to prevent blight, it also keeps a fresh supply of nutrients in the soil.

Mulch Plants As Soon As You Plant

tomato blight
Supporting tomatoes keeps them off the ground and out of harms way

As soon as you plant, mulch the area around your plants immediately. Mulching plants helps to cut down on weeds and keeps the soil temperature regulated.

But more importantly, it helps prevent the spread of soil borne disease! Spores that are alive in the soil can  easily be splashed up foliage directly.

Every time a hard rain hits, your plants have the chance to become infected by the spores splashing up.

It is also important to remove the bottom 6 to 12 inches of your plants foliage for this same reason. Keeping the plants up off the ground helps to keep disease away by keeping soil from directly touching the foliage.

Supporting plants with stakes or cages helps keeps plants off the ground as well.  Product Link : See Tomato Square Cage

Water Carefully

When and how you water can make all the difference in keeping tomato blight at bay. Water in the early morning so tomato plants have time to dry off.

Wet and damp leaves are the ideal ingredient for spores to grow. Watering late in the day or at night will keep plants too moist. That leads to heavy dew, making plants more prone to disease.

When you water, be careful to water only the root zones around tomato plants and not the foliage.

By watering this area, you reduce the chance of splashing spores from plant to plant. Watering is one of those mundane tasks that seem so simple on the surface, but can cause immense damage if done incorrectly.

See : The 4 Secrets To Watering Plants

You may not be able to treat tomato blight effectively once it occurs, but you can definitely help prevent it. As the old saying goes, an ounce of prevention is worth a pound of cure!

Share Your Garden Tips or Garden!

Be sure to check out all of our vegetable garden articles on our Vegetable Tips Page.

Want to showcase your backyard garden or gardening tip on This Is My Garden? Email us today at, and you might be our next feature!

This article may contain affiliate links

watering vegetable plants
← Previous
4 Secrets To Watering Vegetable Plants And Flowers!
mowing mistakes
Next →
Cutting The Grass - 4 Mowing Mistakes To Avoid For A Better Lawn!