Calcium Deficiency In Pepper Plants: Signs And Fixes

All plants need sufficient nutrients from the soil for them to be able to grow up without suffering from health problems. Most gardeners know that their pepper plants need nitrogen along with potassium and phosphorus, as these are included in most all-purpose fertilizers. What some may not know is that pepper plants also need calcium.

Too little calcium can cause major health problems when it comes to the fruit that the plants produce. Calcium plays a major role in how pepper plants’ cells develop. Pepper plants need calcium for the fruits to develop strong, thick walls. Calcium is essential for the process by which cells connect to form tissues. Without the calcium, the tissues won’t be strong and will collapse and leak fluids before eventually dying.

The symptoms of calcium deficiency are the result of tissues dying. The sturdiness of the side walls that comes from the calcium helps the pepper fruit to be more resistant to diseases. Healthy walls also enhance the flavor and texture of the peppers.

How does calcium deficiency happen?

The most common reason for calcium deficiency in pepper plants is that there is not enough of the mineral present in the soil. But that’s not the only factor. In some cases, the symptoms of deficiency are not caused by a lack of calcium in the soil; instead, they are caused by the plant sending calcium to the leaves instead of the fruit. When a plant gets a lot of nitrogen, its leaves start developing at a faster rate. Rapidly developing leaves are better at competing for calcium ions than fruit.

Calcium deficiency also often occurs after a pepper plant has gone without adequate water for an extended period. Water is essential to the calcium uptake process, since the calcium ion follows the flow of water. Calcium gets to the fruits, leaves, and stems via the same mechanisms by which water gets to them. If a pepper plant is not getting enough water from the soil, the fruits may not get the calcium they need.

–> Read more: Watering Pepper Plants: The Dos and Don’ts

Early on as peppers start to grow and develop their waxy impermeable coating, water stops being able to move easily through the fruit’s cells. At the same time, there is not much water being lost to evaporation because of the waxy coating. The combination of factors means that less water is being taken up from the soil because the fruit is not demanding it, and this can also contribute to low levels of calcium in the fruit.

Too much fertilizer in the soil may also inhibit the plant’s ability to take up water and thus reduce its calcium levels as well.

–> Read more: Fertilizing Pepper Plants: The What, When, and How

Any conditions that can damage the plant’s roots can also increase the likelihood of it developing a calcium deficiency. Compacted soil may also contribute to calcium deficiency, since it limits root growth. If the plant’s roots are restricted, it will have difficulty finding water when the soil is dry, and this may cause it to become deficient in calcium.

What are signs of calcium deficiency in pepper plants?

The clearest indication that your pepper plant is deficient in calcium is a condition known as blossom end rot. The condition affects immature peppers — especially the plant’s earliest fruits — and causes them to develop a pale green or yellow sunken area on the bottom of the fruit.

calcium deficiency in pepper plants - blossom end rot
Blossom end rot (seen here) is a sign of calcium deficiency in pepper plants

Despite mainly affecting the early fruits, calcium deficiency symptoms may show up at any point in the plant’s development. The earliest fruits are at a higher risk because the ratio of leaf surface area to fruit surface area is greatest at this point in the plant’s growth. In other words, there is more leaf to compete with the fruit for calcium. The pale sunken area may blacken over time. The reason for the change in coloration is that the sunken area tends to be an entry point for soft-rot bacteria and fungus to infect the pepper.

There are disorders with similar symptoms as calcium deficiency that might lead to a wrong diagnosis. Fruit anthracnose and sunscald may be mistaken for calcium deficiency; in both cases, the symptoms may seem similar, but the blemish will appear on side walls instead of on the blossom end of the fruit or the lower side wall of immature fruit. You will never see signs of calcium deficiency on the stem side of a pepper.

How can you fix calcium deficiency?

If the soil in your garden lacks the calcium your pepper plants need, you may be able to add it in the form of fertilizer. One way to do this is with calcium nitrate, which is water-soluble.

You can supply pepper plants with calcium nitrate via drip irrigation, which will get it to the roots efficiently. Start adding calcium when the plant is blossoming and continue until the fruit has set. This represents the most crucial stage in the pepper’s development and when it is most likely to show symptoms of calcium deficiency.

If the calcium deficiency has been caused by insufficient watering, you can fix it by providing the plants with the water they need. Keep the soil moist without overwatering. Mulch is an effective tool to keep your soil from drying out. Adding a layer of mulch will also keep your pepper plants at the optimal temperature for calcium absorption.

Foliar sprays are sometimes recommended as a solution for calcium deficiency, but they do not work since calcium is transpired within the plant. There is no pathway for it to move from the leaves to the fruit.

How do you prevent it in the first place?

Before planting peppers, test your soil to see whether it lacks calcium and then add it if necessary. It is always smart to test the soil in a location to find out which nutrients it lacks so that you can formulate your fertilizer to compensate. The best fertilizers for increasing the calcium level in the soil before planting include gypsum and bone meal, which are organic and won’t result in the addition of excessive nitrogen to the soil. You can also prevent calcium deficiency in the future by adding eggshells to your compost.

Water management is a key element in preventing calcium deficiency. You will need to provide your pepper plants with the water they need, especially during dry parts of the year. Increase your pepper plant’s water during the point in the season when they are setting fruit. Prepare the soil for your pepper plants thoroughly to avoid compaction so that their roots can take up water. You can check to see if the soil around the pepper plants is moist enough by feel. If the soil is sufficiently moist, you will be able to form it into a ball without it breaking apart.

Carefully control how much nitrogen you provide to your pepper plants. While nitrogen will enable the plant to develop its foliage, too much can predispose the plant to calcium deficiency.

UPDATE NOTICE: This post was updated on March 11, 2022 to include new content.
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