Symptoms of Nutrient Deficiency and Toxicity in Hydroponics

Symptoms of Nutrient Deficiency and Toxicity in Hydroponics

One of the most important elements of your hydroponic garden is the nutrient mixture that you provide to your crops. Without the proper balance of the essential nutrients necessary for each stage of life, the garden may show symptoms of nutrient deficiency or, in rare cases, nutrient toxicity. Each nutrient shows different indicators when there are dosing issues with the nutrient mixture since each element does something different for the plant’s growth. Detecting the symptoms of nutrient deficiency and toxicity in hydroponics early on can help you identify the problematic nutrient and correct its levels.

Signs of Nutrient Deficiencies

Many hydroponic gardeners, especially new hydroponic gardeners, may be too careful with the nutrients they add to the nourishing nutrient solution. However, being too careful can have devastating consequences on the growth of your plants—it’s sometimes even more destructive than too high of a concentration of a nutrient.

Every plant displays nutrient deficiencies differently, if at all. In some cases, you may not know about a nutrient deficiency until you harvest your crop. While many plants share these signs of nutrient deficiencies, you should take note of anything unusual going on in your garden and research it carefully.


As it’s one of the fundamental building blocks of life, a deficiency in nitrogen can ravage your plants. Plants that are lacking in nitrogen can’t make chlorophyll as easily, meaning that their leaves will begin to lose their green coloration.

Known as chlorosis, the loss of color begins at the lower, older leaves and makes its way up to the new growth. With a severe enough nitrogen deficiency, the plant can turn entirely white, and its growth can become stunted.


A lack of phosphorus can be difficult to detect early on—leaves may turn dark green, and the plant may not grow that large. Phosphorus affects the cell structure of your plants; low phosphorus means weaker plant growth. With severe, untreated phosphorus deficiencies, the older leaves may turn dark purple. This happens after the plant has too many carbohydrates because its photosynthesis energy production process is not slowing down.


Plants with potassium deficiencies become vulnerable to many things that they’d otherwise be able to combat—consider it like immunodeficiency in humans. The tips of the plants’ leaves may scorch from the light; outdoors, the plant would be much more vulnerable to frost and wind damage. Potassium-deprived plants can also experience chlorosis between their leaf veins on lower leaves.

Because potassium is such a necessary nutrient, parts of the plant may die, especially on its leaf tips—otherwise known as necrosis. Necrosis can look like dead spots or dying leaf tips and cause wilting.


If a plant is experiencing a sulfur deficiency, the entire leaf can turn yellow—starting with the youngest leaves. Unlike the interveinal chlorosis symptoms mentioned above, sulfur deficiency causes even the veins to turn yellow. The leaves will then curl inward.


When the only symptom you notice is interveinal chlorosis beginning from the leaf tips on the lower leaves and working its way up, your plant may be experiencing a magnesium deficiency.


A lack of calcium can create some visually unappealing plant growth. Younger leaves and fruit may not grow in correctly and can affect the future maturation of the plant. Some fruits, such as tomatoes and peppers, have a problem called “blossom end rot,” where the bottom of an otherwise healthy-appearing fruit looks brown and rotten.


Consistently checking your pH levels can help you prevent a serious iron deficiency. If you notice yellowing leaves on the most recent growth and you have a higher pH than 7 in your nutrient solution, you may be facing low iron levels. In nutrient solutions that are too basic, the plants cannot absorb the iron.


With iron deficiency usually comes manganese deficiency, as they’re both available in similar pH levels. Growers often confuse the symptoms of iron deficiency and manganese deficiency since they’re hard to tell apart. Without manganese, the leaves will begin to turn yellow, starting with the topmost leaves. However, if you don’t treat manganese deficiency in time, you’ll see necrosis develop in splotches on the leaves.


Plants don’t need a lot of boron to stay healthy, but the effects of boron deficiency can be especially calamitous for flora. Without water-soluble boron, stems and roots die and rot, inviting disease or fungi. Fruits also suffer from boron deficiency with deformities and unique conditions that are specific to the fruit itself. Leaves may wither, grow thicker, or develop necrotic spots.


Zinc deficiencies come with diverse symptoms that often affect the youngest growth. You’ll notice stunted leaves, chlorosis, deformed leaves, necrotic spots, and leaves with wavy outlines.


If a plant experiences copper deficiency, you’ll notice younger leaves become darker green in color and twist up. They won’t grow as big, and the leaves may develop necrotic spotting.


In flora suffering from molybdenum deficiency, you’ll notice that older leaves suffer from chlorosis first before it moves up to the entire plant. New growth will come in extremely twisted and won’t live very long.

Symptoms of Nutrient Toxicity

Nutrient toxicity, the opposite of nutrient deficiency, rarely happens with careful hydroponic gardeners; however, it’s not entirely out of the question. Commonly, hydroponic gardeners will use chlorinated water and pair it with chlorine in their nutrient solution, causing chlorine toxicity—which can cause leaf burn, chlorosis, and leaf splitting.

You may notice nutrient toxicity visually through symptoms similar to those of deficiencies. However, many of the essential nutrients, such as zinc and copper, are lethally toxic to plants when you use them in excess.

Check your electrical conductivity (EC) regularly if you’re concerned about nutrient toxicity; a higher EC than usual indicates that you need to dilute your solution with water, while a lower one means you may need more nutrients.

The best way to avoid all the symptoms of nutrient deficiency and toxicity in hydroponics and keep your plants well-fed is to purchase a powder fertilizer for hydroponics that carefully considers your system’s needs. At FloraFlex, we don’t just provide you with one type of fertilizer; we put your garden on a regular Full Tilt schedule that feeds your plants the proper nutrients based on their stage of life. With our convenient system, you won’t feel stressed picking out all the right nutrients—no matter how new you are to gardening.

Symptoms of Nutrient Deficiency and Toxicity in Hydroponics