Calcium Deficiency in Plants: 4 Signs of Calcium Deficiency

An adequate calcium concentration keeps older leaves healthy and helps younger leaves grow. When plants don’t have enough calcium, they can discolor and rot both above and below ground. Gardeners should strive for a well-managed balance of factors, such as a healthy soil pH and fertilizer containing essential nutrients, to prevent a lack of calcium and other nutrients.

There are several primary causes of calcium deficiency in plants, usually caused by some sort of imbalance in soil nutrients or a breakdown in transpiration (the process by which water travels through plants to ultimately evaporate in the air). Calcium is a cation (a positively charged ion) and needs room to bind with plant cell walls. When other nutrients crowd out this ability, they prevent the uptake of calcium.

The transpiration process—the evaporation of water from plants’ leaves—can break down when plants encounter adverse climatic conditions, leading to a lack of calcium delivery to plant tissue. Calcium moves through the xylem of plants as evaporation sucks up the nutrient through the leaves into the air alongside water. By ensuring adequate irrigation below ground and the right balance of humidity above ground, the transpiration process can prevent deficiencies from arising.

It’s easy to detect a lack of calcium in your plants. Keep an eye out for these four key calcium deficiency symptoms:

1. 1. Curling leaves: When plants lack sufficient calcium, their new growth begins to curl. Some gardeners refer to this as the plants developing “parachute leaves.” When you notice new leaves turning in on themselves, it’s worth considering whether a lack of calcium could be the reason.
2. 2. Discoloration: Brown spots of tip burn on leaf margins can be proof of a calcium deficiency, as can yellowy chlorosis throughout your leaves as a whole. If you leave this unchecked, your leaves might become completely necrotic. Still, there are many other reasons for plant discoloration, so you should perform a soil test to help determine what your plant lacks.
3. 3. Rot: On new leaves, fruits, and flowers, rot of all kinds might hint at a calcium deficiency. For that matter, if you notice blossom end rot above ground, it’s likely there might be root rot below ground, too. Act quickly to prevent unnecessary necrosis.
4. 4. Slow growth: Calcium-deficient plants are slow growers. If your plants are taking an inordinate amount of time to reach maturity, you should check your soil to see if you’re dealing with a calcium or nutrient deficiency in general. It might not be the case, but ruling it out will still help you get to the root of the problem.

Calcium deficiencies hamper plant growth. Here are seven approaches to preventing and mitigating the problem from cropping up:

1. 1. Add calcium sources. There are various sources you can use to enrich your soil with calcium. Try a liquid foliar fertilizer with calcium nitrate and calcium chloride, or try adding organic matter, such as bone meal, dolomite lime, eggshells, or gypsum. The important thing is to deliver an adequate nutrient solution to your calcium-hungry plants, whether it’s natural or synthetic.
2. 2. Act to prevent all deficiencies. When your plant becomes deficient in one nutrient, it can cause a chain reaction, and its internal system might struggle to process other nutrients, too. Additionally, keep in mind that boron deficiencies and magnesium deficiencies both mimic the signs you’d see if your plants were suffering from a lack of calcium. To keep your young leaves healthy, make sure they’re getting all their nutrients.
3. 3. Analyze for transpiration issues. Plants use xylem instead of phloem pathways for calcium uptake, and low transpiration can interrupt these processes. Transpiration itself—the natural loss of water through the leaves—can suffer when the plant lacks calcium. If you notice the symptoms of a calcium deficiency, make sure your plants have enough irrigation below ground and that you’re watering them regularly, too. Calcium travels up into the leaves via water evaporation, and they need plenty of moisture for this transpiration to occur.
4. 4. Balance with other nutrients. Plants need both macronutrients (like phosphorus, potassium, and calcium) and micronutrients (like manganese, zinc, and iron). Keeping all of these in balance in your soil ensures the right amount of calcium can bind with other nutrients through ionization. Keep a steady eye on the nutrient balance in your soil—it is fairly common to deal with multiple nutrient deficiencies simultaneously. For instance, cal-mag (or calcium-magnesium deficiencies) can affect your plants even more drastically than just one deficiency would.
5. 5. Check pH levels. Aim for a well-balanced pH to ensure your newer leaves sprout with enough access to calcium. Strive for a good middle ground between alkaline and acidic soil. The soil pH itself should be around 6.5–7.5.
6. 6. Manage the climatic conditions. Climate contributes a lot to a plant’s ability to access calcium. Too much high humidity or heat can affect the transpiration process, which will cause calcium levels in your plants to diminish. Try to make sure your plants only deal with moderate humidity levels and temperatures whether they’re outdoors or in a grow room.
7. 7. Test the soil. Use a professional soil test to discern any deficiencies in your soil. By checking out what makes up the structure of your growing medium, you can diagnose whether a calcium deficiency is the cause of your plants’ problems in the first place.

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