How To Prevent Yellow Shoulder Disorder On Tomatoes

Red tomato with yellow top, diseased vegetable.

Tomatoes are fun and rewarding to grow. There can be challenges along the way such as diseases and pests. Two of the most common tomato disorders you will likely battle are Blossom-End Rot and Yellow Shoulder (sometimes called Green Shoulder). This article will help you learn how to identify Yellow Shoulder, how to prevent it, and what tomato varieties to choose that are less susceptible to Yellow Shoulder.

Disease vs Disorder

a closeup of rotten tomatoes in the garden

The first thing to know is Yellow Shoulder is not a disease; it is a disorder. It is an important distinction to make because 99% of disorders can be cured by changing the way we garden. Whereas, diseases typically need to be foiled by a fungicide.

What Is Yellow Shoulder Disorder?

Yellow shoulder disorder on tomato
Photo By Bruce Watt, University of Maine, Bugwood.org

Basically, yellow shoulders are due to a nutrient deficiency, specifically potassium. It is quite complex to understand exactly why it happens. Agricultural scientists and universities have been studying it for years. It has been difficult to figure out because it is triggered by many different environmental and cultural factors, but all gardeners want to know is how to prevent it.

Choosing Tomato Varieties

Tomato plant growing fresh on the vine

Planting less susceptible cultivars is a good start. If you have had certain varieties develop yellow shoulders, don’t plant those again for a year or two.

Many varieties listed as “good canners’ ‘ like Amish Paste, BoxCar Willie, Marglobe Improved, Old Brooks, and Rutgers are less susceptible, but lots of research has to be done to identify specific named varieties for this issue.

How To Prevent Yellow Shoulder Disorder

Farmer giving granulated fertilizer to young tomato plants

As mentioned, this disorder is triggered by a nutrient deficiency. Using a good balanced tomato specific fertilizer from spring all the way through the growing season will help.  Tomato Maker and Dave Thompson’s Organic Healthy Grow – Tomato Food are tomato specific fertilizers perfect for helping to provide balanced nutrition for your tomato plants.

Supplies For All Your Gardening Needs

Adding 3 to 4 lbs per 100 sq. ft. of Neptune’s Harvest Organic Kelp Meal (1-0-2) to garden beds will help prevent yellow shoulders.

Checking and double-checking soil pH is important too. Soil that is slightly acidic, in the range of 6.0 to 6.5 is also helpful for prevention.

Other Recommended Reading

Little white cup of espresso coffee, opened book, blue semi-transparent vase with purple lilac flowers on rustic wooden table in the garden at spring morning after sunrise or at evening before sunset

With a little bit of attention and effort, you can avoid Yellow Shoulder. You’ll be able to produce an abundance of healthy, delicious tomatoes your whole family can enjoy.

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