Iron Chlorosis in Young Blueberry Plants

As a horticultural educator, berry crops fall under my description, and they include strawberries, blueberries, and breeze. Occasionally there may be a small amount of unknown fruit information information but in general these three are very common in our area.

These crops are different from most vegetable crops in that they are long-lasting and will not be replanted in the next growing season.

There can be many reasons why a new plant may not grow at all. My first question is always when it comes to blueberries. “What is your soil pH?”

Preparing the soil for blueberry planting cannot be overstated, and failure to test and adjust the soil before planting can result in problems that are not easily tolerated. A.D. In 2020, Kathy Demchak of Penn State wrote a good article. “Keys to Establishing a Successful Blueberry Plant” You can easily find it by searching online. She listed five keys in the article, which include pH, planting method, mulching, irrigation and proper nitrogen use.

If you are planning to plant a new blueberry, I recommend you read the article. This week, I focus on iron chlorosis and high soil pH.

Chlorosis is a yellowish color of leaf tissue. Plants need iron to make chlorophyll. Do you remember from high school biology class that chlorophyll green plants? If not, consider this reminder!

When plants do not have iron, the leaf’s arteries become green, but due to chlorophyll deficiency, the leaf between the leaf’s arteries becomes yellow and we call this chlorosis. You can hear it said “Your plant is chlorotic.” It all means the same thing – you have yellow leaves.

Iron chlorosis usually appears on the small leaves near the tips of the leaves. In blueberry shrubs, you may notice this sign on a part or a branch. Also, the growth of new shoots and leaves may be less than usual.

Correction of iron chlorosis in a blueberry plant can be temporarily alleviated by the use of foil or soil chile. You can find this in many grocery stores. However, this is not a long-term solution. As soil pH increases, iron availability decreases.

Frankly, your soil contains the iron that the blueberry plant needs, but it cannot be used because the soil pH is so high. Correction of soil pH is a priority. Blueberries require low pH, 4.5-5.0 is the best. Pennsylvania’s best farmland is not in this region. It is another reason to acidic before planting blueberries.

Powdered or concentrated sulfur is recommended to lower soil pH during the planting of blueberries, although sulfur pellets can sometimes break down and take longer to react with the soil. The best way to use sulfur is to apply it in early spring or autumn and apply it all over the field.

Of course, if you already have plants in the ground, this is impossible, because you do not want to damage the roots. In this case, I recommend applying sulfur not only on the basement but also on the entire planting beds. Sulfur can be broken down by rain, so do it before you predict rain.

Remember that you may not see any pH changes in your soil for at least 6 months. Do not use aluminum sulfate to make the soil acidic because aluminum is present in your soil and can be toxic to blueberries.

True, some common fertilizers, such as urea, ammonium nitrate, and ammonium sulfate, cause acidic conditions. However, in order to avoid overuse of nitrogen and to burn plants, these products are only used as the main target fertilizer and as an additional benefit of soil acidity.

Soil tests are usually collected in the fall or early winter, although they can be done at any time of the year. It is important to do this regularly, especially if you are trying to fix the soil pH problem. Take a soil test kit from your County Extension Office to find out the pH and nutrients in your soil. At $ 9, it’s a great bargain, and gives you a good idea of ​​how to prepare your soil for blueberries. Be sure to check the delivery form for blueberries.

The laboratory then offers recommendations for that particular crop. We can guide you to fill out the form and tell you the best way to take a soil sample.

For questions about this or related topics, please email the Junior County Extension Office at or (717) 436-7744.


Leah Franck is a teacher at Pen State Extension Horticulture.

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