Nutrient Deficiencies: Why Your Aquarium Plants Are Dying

Are your plants still dying despite having the best planted aquarium setup? It could be from a lack of nutrients. Your plants may be lacking key building blocks, even if you regularly fertilize them. This article will teach you how to spot the signs of nutrient deficiency so you can prevent your plants from reaching death’s door.

Illustration of a healthy, normal-looking leaf

Types of Nutrient Deficiencies in Plants

Nitrogen Deficiency

Low nitrates are a common problem in planted tanks, especially with beginners in the aquarium hobby who have been taught to do routine water changes every week (without testing for the actual nitrate level). This habit, while fine for fish only tanks, can lead to a lack of nitrogen, even if you are regularly dosing fertilizers. Classic signs of nitrogen deficiency include old leaves turning yellow and translucent, especially starting at the leaf tips, as the plant consumes nutrients from its old leaves at the bottom in order to make new leaves at the top.

Signs of nitrogen deficiency on old leaves

You may also run into nitrogen deficiencies if you don’t follow the recommended fertilizer dosage instructions. However, four months later, when your plants are three times their size, you still need to do the same amount. Just as you automatically feed more food if you add more fish to an aquarium or if they grow bigger over time, you need to feed your plants more as they get taller or propagate.

The same principle applies if you prune or remove a bunch of plants – make sure to lessen the amount of nitrogen provided. It is a good idea to match the amount you apply to fertilizer (whether it be liquid fertilizers for plants who feed from the water column, or root tabs for those plants who feed from their roots), with the growth of your plants.

If you notice translucent or yellow leaves on a new plant, it may not be due to nitrogen deficiency but melting. Most plants that you buy online or locally were raised in water. Emersed (or out of water) leaves can melt and make room for submerged-grown or underwater-grown leaves. This melting effect may even occur if you buy a submersed-grown plant from another hobbyist because the plant needs time to get accustomed to your tank’s different water parameters.

For example, stem plants that are melting tend to lose their lower leaves, leaving a bare stem on bottom with new leaves on top. Once the stem has completely transformed to only submerged-grown leaves you can remove the top and replant it. Amazon swords, cryptocoryne and stem plants are well-known for melting in new environments. Java fern and anubias are, however, quite hardy.

Iron Deficiency

Lack of iron causes plants to yellow or become pale on their new leaves. However, leaf veins that are darker in color and that have a lower level of iron content will not show any signs of yellowing. On the other hand, older leaves are usually normal.

Signs that new leaves have iron deficiency

High iron concentrations can be difficult to include in standard fertilizers. Instead of using more liquid fertilizer, you can buy an iron-specific supplement. Adding extra iron can also be used to enhance the color of red plants.

Potassium Deficiency

This condition is easy to diagnose because the plant’s leaves will develop distinctive pinholes that are sometimes rimmed with brown or yellow. Anubias and java fern thrive in areas with higher potassium levels, so be aware of these signs. There are many options for potassium-specific supplements, but Easy Green already has extra potassium. Therefore, treatment can be a simple matter of just dosing more of our broad-spectrum fertilizer.

Signs of potassium deficiency on old leaves

Phosphate Deficiency

Another macronutrient that plants consume is phosphate, which is similar to nitrogen. Older leaves are more affected, and they will develop yellow spots with brown spots. As the leaves begin to die, green spots may form. This condition is more uncommon, since fish foods like flakes contain phosphates. However, sometimes people will put phosphate-absorbing pads in their filters to prevent algae growth, and that ends up starving the plants of phosphate.

Signs a phosphate deficiency in old leaves

Magnesium Deficiency

Lack of magnesium looks similar to a lack of iron, where leaves turn lighter in color with dark veins, but in this case, the deficiency affects older leaves instead new ones. Sometimes the leaf edges may droop as well. Magnesium is a common ingredient in general-purpose fertilizers. You can either add more magnesium to your fertilization regimen or use Epsom salts or a magnesium supplement to get this nutrient. Note: this condition is often related to calcium deficiencies.

Signs of magnesium deficiency in old leaves

Calcium Deficiency

You may notice new leaves becoming twisted or gnarled if you have a calcium issue. Low water hardness is often a sign of calcium, magnesium, or manganese deficiency. You may need to supplement your water with special salts if you have soft water, RO/DI (reverse-osmosis deionized), or crystal shrimp. You can also gradually increase calcium levels and water hardness by putting crushed coral in the substrate or filter, adding Wonder Shell into the aquarium, or dosing Seachem Equilibrium minerals.

Signs of calcium deficiency on new leaves

How to Fix Nutrient Deficiencies

In order to properly treat your plants, identify the nutrient deficiency and how you’re going to fix it (e.g., add more fertilizer or specific supplements, increase the water hardness, feed more fish food, and/or remove some plants). You should ensure that the fertilizer you use has the correct nutrient. (For example, Easy Green doesn’t affect water hardness or calcium levels very much.)

Most deficiencies can be solved by increasing your dosage of all-in-one fertilizers because if you’re missing nitrogen, for instance, you’re likely missing other nutrients as well. Your plants will soon run out of nutrients if you only give them a nitrogen supplement. However, dosing more Easy Green or Easy Root Tabs provides more of the macronutrients and micronutrients your plants need (and at all the right concentrations).

EasyGreen is the best choice for aquarium plants. This fertilizer was initially developed for use in our retail store. It is easier to use than other supplements, has a higher nutrient concentration and is affordable. Easy Green is a liquid fertilizer that contains all the nutrients your aquatic plants require to thrive. Unlike other ammonia-based fertilizers, Easy Green is completely safe to use with fish, shrimp, snails, and other invertebrates.

It takes about two to three weeks to notice a difference in the plants. Then you can assess if your actions made a difference. Based on the results of the experiment, you can adjust your fertilization schedule to reflect what the plants are actually eating. Plant aquariums are an ever-changing landscape. Your fertilizer requirements will change as your plants grow, the leaves are cut, and plants are removed or added to. Take care to examine your plants on a regular basis and jump on any nutrient deficiencies, and you’ll create a beautiful, thriving planted aquarium.

Get our infographic on plant nutrient deficiencies for quick reference here: