With each passing garden season, it seems we get more and more emails asking for advice on how to prevent tomato blight from attacking and destroying tomato plants.
Tomato blight can be a serious issue for gardeners. In fact, it can quickly decimate seemingly healthy plants in just a matter of weeks.
On top of that, it can spread equally fast from plant to plant, wiping out an entire crop of tomatoes.
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What Is Tomato Blight
So exactly what is tomato blight? Blight is a soil borne, fungal disease that attacks plants by destroying foliage and in many cases, the fruit as well.
There are actually two types of blight, early season blight, and late season blight. Although they are slightly different in cause and effect, both bring serious harm to your plants. (more on that later)
Making matters worse is that once established, tomato blight can infect the soil in a given area for many years to come. And that, unfortunately, means future plants are extremely vulnerable as well.
But as deadly and defeating as the blight can be, there are three simple tips that can help keep it from finding its way to your tomato crop. And as luck would have it, all three help in preventing both early and late season blight. Even better, they couldn’t be more easy to do!
3 Simple Tips To Help Prevent Tomato Blight
#1 Crop Rotation
Without a doubt, crop rotation is the single biggest weapon against tomato blight. Growing tomatoes in the same location year after year is like putting out a welcome mat for blight.
Because blight is a soil-borne disease, it relies on the soil to keep its spores alive from year to year. And once established, those spores can remain alive for multiple years, simply lying in wait to infect the next crop of tomatoes planted above.
But by moving and rotating your plants from year to year, you can disrupt that process. To use as an effective tool against blight, tomatoes should not be planted in the same location for at least 3 years. And if your plants have become infected with blight, it’s best to leave that space tomato free for at least 5 years to allow the spores to die off.
This also applies to the soil in containers and raised beds. In fact, container soil should be replaced every year, not just to fight blight and other disease, but to rejuvenate the nutrients for new plants.
Container or bucket plants can actually be a great way to eliminate blight entirely. By using new soil each year, the chance of spores finding a permanent home vanish. See : How To Grow Tomatoes In Buckets
#2 Use Mulch To Cover The Soil – Preventing Tomato Blight
Beyond crop rotation, mulching is the next best line of defense against blight. If blight spores are in the soil, they find their way to plants not through the roots, but via the air.
The spores can be carried on to plants from the wind, or by splashing on the foliage from rain or watering. But by covering the soil below the plants, you greatly diminish the opportunity for spores to find a home.
Mulch the soil around plants with a thick 4 to 6″ covering of straw or shredded leaves. Not only will this help reduce the spread of blight, it also has many additional benefits for your tomatoes.
Mulch helps suppress competing weeds, all while helping to retain moisture in the soil. It is certainly a win-win when it comes to preventing tomato blight and helping your plants!
Staking or supporting plants with a cage or trellis will also help to keep foliage from sprawling on the ground and touching spores. In addition to giving the plants support, keep the base of your tomato plants pruned up as they grow.
Low branches that allow the foliage to touch the ground are an easy path for spores to find a home. It also helps to keep your plants safe from toppling over due to excessive weight. (See : Why & How To Stake & Prune Tomatoes)
#3 Don’t Compost Tomato Plants
Finally, although it may seem like a good idea, tomato plants should never be put into your compost pile. And that includes any branches or stems pruned of throughout the season.
Tomato plants are notorious for harboring pests and disease. And of course, blight certainly falls in that category. But most home compost piles simply never reach hot enough temperatures to kill the spores that cause blight.
At season’s end, pull your plants and remove them from the garden. Be careful as you do to not place them down on nearby soil. Instead, place them into a wheelbarrow or bucket and remove from the space.
A Few Final Notes On Preventing Tomato Blight
As mentioned earlier, there are two types of blight, early season and late season. Although both are very harmful to plants, late season blight is by far the most deadly.
Early season blight usually will show symptom when tomatoes first start appearing. It starts with a few small brown scars on the foliage. Next, the foliage turns yellow, and then brown as it dies off.
Early blight will not kill the plant entirely, nor the tomatoes, but if left unchecked, the foliage will die off. It results in plants that simply can’t grow, a less than desirable tomato harvest.
To keep in check, quickly remove any stems or foliage that show these early signs. Be careful when pruning to not let the infected branches touch other leaves.
Late season blight is much more difficult and deadly to the entire plant. Unfortunately, once the symptoms appear, there is little you can do except remove the plants.
Late blight starts on the edge of leaves as black spots or black curls. From there, it takes over the plant, including the fruit as well. Eventually, the entire plant will love its cover of foliage, and the plant will die.
But hopefully, by employing the three simple methods above – that can be avoided. Here is to avoiding the blight – and to a great crop of tomatoes this year! Happy Gardening – Jim and Mary.
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