Nutrient Deficiencies: why your Aquarium Plants Are Dying


Nutrient Deficiencies: Why Your Aquarium Plants Are Dying

You have the perfect aquarium, but your plants keep dying. It could be from a lack of nutrients. Even if you are regularly dosing fertilizers, your plants might still be missing key building blocks that prevent them from growing and thriving. In this article, we want to teach how to recognize the first signs of nutrient deficiencies so that you can take appropriate measures before your plants reach 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. Old leaves that turn yellow or translucent are classic signs of a nitrogen deficiency. This happens because the plant uses nutrients from its bottom leaves to make new ones.

Signs that old leaves may have a nitrogen deficiency

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. Our recommendation is to try and match the amount of fertilizer you use (whether it’s liquid fertilizers for plants that feed from the water column or root tabs for plants that feed from their roots) with your plants’ growth.

If you notice translucent or yellow leaves on a new plant, it may not be due to nitrogen deficiency but melting. Many plants bought online or locally were grown in water. These emersed leaves will eventually melt to make way for smaller, healthier, submerged-grown (or underwater) leaves. This melting effect can occur even if the plant is purchased from another hobbyist.

When stem plants are melting, they tend to lose the lower leaves. This leaves a bare bottom and new leaves on top. You can trim the healthy-looking top off your stem plant once it is fully grown to submerged-grown foliage. Then, replant the stem so you don’t see any skinny stems. Amazon swords, stem plants and cryptocoryne plant are known for melting in new environments. Anubias and Java fern, however, are much more resilient.

Iron Deficiency

Plants without iron show yellowing or pallor on their newest leaves. Leaf veins that remain darker in colour are a sign of iron deficiency. Older leaves look more 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. To enhance the color of red-colored plants, you can add extra iron.

Potassium Deficiency

The pinholes on the plant’s leaves can be easily identified. They may sometimes have yellow or brown edges. Anubias and java fern thrive in areas with higher potassium levels, so be aware of these signs. Although you can purchase a potassium-specific supplement to help with these issues, we fortify Easy Green with additional potassium. It is easy to simply add more of our broad-spectrum fertiliser.

Signs of potassium deficiency in old leaves

Phosphate Deficiency

Another macronutrient that plants consume is phosphate, which is similar to nitrogen. The older leaves will be most affected. They will turn yellow and develop soggy brown spots. Green spots of algae may also form as they begin to break down the dying leaves. This condition is more uncommon, since fish foods like flakes contain phosphates. To prevent algae growth, some people may use phosphate-absorbing pads to their filters. This can lead to the plants being starved of phosphate.

Signs of phosphate deficiency on 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 typically included in most general-purpose fertilizers, so dose more of it as part of your fertilization routine or consider using a magnesium supplement or Epsom salts to supply this nutrient. This is often due to calcium deficiencies.

Signs that old leaves may have magnesium deficiencies

Calcium Deficiency

New leaves that grow in a twisty, gnarled manner are usually indicative of a calcium or hardness problem. In fact, calcium, magnesium, and manganese deficiencies often coincide with low water hardness. These minerals may be required to maintain the health of your crystal shrimp or discus if you have soft or RO/DI water. You can also slowly increase calcium levels and hardness by adding crushed coral to the substrate or filter, Wonder Shell to the aquarium, or 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. Easy Green does not affect water hardness, calcium, or other levels.

You can solve most deficiencies by increasing your intake of all-in one fertilizers. For instance, if you are missing nitrogen, it is likely that you are also missing other nutrients. If you only dose a nitrogen supplement, your plants will probably run out of other nutrients, and new deficiencies will start to pop up. 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).

Simple Green is our recommended fertilizer. 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 usually takes between two and three weeks for your plants to show a change. Once you do, you can determine whether your actions have helped or hurt them. Based on the results of the experiment, you can adjust your fertilization schedule to reflect what the plants are actually eating. Planted aquariums are an ever-evolving landscape with fertilizer needs that must change as plants grow over time, leaves are pruned, and plants are added or removed. 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: