Can You Use Fish Fertilizer on Cactus Plants?

When plant enthusiasts introduce a tolerant and tough cactus into the rest of their indoor plant collection, they see a difference in the endurance level of most houseplants and the humble cactus.

However, although cacti are known for having remarkable resistance and can survive for multiple decades, it is incorrect to assume that the desert plant needs no fertilization at all.

At times, inconsistent poor care or prolonged periods of unideal living conditions in the USA can hurt a cactus’ natural growth rate and immunity. In such situations, using a high-quality plant fertilizer, such as a nitrogen-rich fish emulsion, can help bring the cactus back to its former glory.

Keep reading to learn why most plant parents ignore their cactus’ fertilizing requirements and when and how to use fish fertilizer to keep your cactus healthy and thriving.

Why Do People Ignore a Cactus’ Fertilization Needs?

According to recent statistics, almost 66% of Americans own at least one house plant. Since cacti are generally one of the easiest indoor and outdoor plants to look after, it is safe to assume that many Americans own some species of the Cactaceae family.

However, while most people need very little plant knowledge to care for their thorny desert plant, knowing when a cactus is being pushed to its limits is still important.

Cacti are naturally adapted to thrive under deprivation and can demonstrate unmatchable resistance against extreme temperatures and living conditions.

Since cacti have no leaves, their bodies are designed to minimize water loss which helps them retain their hydration and produce plant food even when water is scarce.

Moreover, a cactus’ thick trunk-like stem helps the plant conserve a significant amount of water for a long period, and its unique root system helps ensure that the plant can reach and absorb any amount of moisture it can find in its surroundings.

You’re not wrong for assuming that a plant as tough as the cactus will be fine without your attention.

However, despite the relatively high tolerance, a cactus is a living species at the end of the day. Although the plant has the natural ability to stand tall against most unfavorable conditions, it will succumb if deprived of proper micronutrients and minerals. 

This is why you must fertilize an indoor potted or outdoor planted cactus at least once every year, ideally during late fall.

Before we talk about using fish fertilizer, let us first highlight the signs that indicate your cactus’ poor health.

How to Know When Your Cactus Needs Fertilizer

Identifying the signs of a weak or dying cactus is usually not easy. However, if you are interested in boosting your desert plant’s health and growth rate, you must know when to fertilize a cactus.

Generally, the best time to fertilize a cactus is during its active growth period. While most cacti grow throughout the year, their growth rate receives an incredible boost when they are fertilized at the right time.

Hence, add suitable fertilizer to your cacti plant during late fall or between March to September. If you miss this active growth period, your cactus will grow insignificantly throughout the rest of the year.

Moreover, other signs that indicate the need for a cactus’ fertilization are as follows:

  • Stunted growth. For instance, if you own a certain species of the Cactaceae family that is supposed to grow at least three inches in a year, and your cactus only manages to grow a single inch, you know something is holding the cactus back.
  • Its trunk loses its deep green color and turns yellow or pale.
  • The cactus has grown no new limbs in a long period.
  • The cactus is losing its thorns.

What is a Fish Fertilizer or Emulsion?

As mentioned above, fish fertilizer is one of the best plant fertilizers that you can use for a weak or poorly growing cactus.

As the name suggests, fish fertilizer is prepared using a whole fish carcass, including its bones, skin, scales, and other nutritious plant nutrients and ingredients.

Fish emulsion or fertilizer contains high amounts of nitrogen, phosphorus, and magnesium and is usually used to massively improve the overall fertility and quality of the potting soil, which then directly impacts the growing plant’s appearance, health, immunity, and growth rate.

Plants fed fish fertilizer at least once a year, especially during their active growth periods, generally have higher growth rates and a better chance of protecting themselves against common plant diseases, fungal infections, and pest infestations.

Hence, by adding a high-quality fish fertilizer to your weak or poorly growing cactus plant, you will immediately help it restore its natural tolerance, which will give it the boost it needs to grow taller and stronger and develop new cacti limbs.

Pay attention to the steps below to prepare your cactus plant’s fish fertilizer at home.

How to Make Fish Fertilizer at Home

  1. Begin the process by mixing a whole fish carcass into the water, ensuring the ratio between fish and water is 1 to 3.
  2. Once your diluted fish mixture is prepared, add one part molasses to at least three parts of the fishy solution.
  3. Moreover, add a few tablespoons of EM1 or lab microbes to the solution and mix well.
  4. Leave it in its container for at least a month.
  5. Finally, strain the fish fertilizer through a fine mesh or cheesecloth, and only store it in a dark and cool place.

This fish emulsion does not go bad and can be used to fertilize all indoor and outdoor plants.

How to Use Fish Fertilizer on Your Cactus

Now that you know when to fertilize your indoor potted or outdoor planted cactus and how to prepare your own DIY fish emulsion, let’s talk about how to add fertilizer to your cactus.

Cacti are plants that thrive on deprivation. When you overwater your cactus, you increase its chances of developing root rot.

Whenever you fertilize your cactus plant with a watery fish emulsion, make sure you water the desert plant accordingly.

Moreover, while fish fertilizer can do wonders for a slow-growth cactus, too much fertilizer will do the opposite.

Follow the steps below to know how to add fish fertilizer to your cactus:

  • Fish emulsions are strong and should not be handled carelessly.
  • Mix half an ounce of the emulsion into one gallon of water to prepare the perfect fertilizer for your cactus.
  • Add the fertilizer to a spray bottle and slowly add it to the cactus’ soil, one spray at a time.
  • Wait for the sprayed fertilizer to fully soak into the soil before you add any more.
  • Moreover, tap the sides of the cactus’ pot to shake and drain out any excess fish fertilizer from the drainage holes.
  • Finally, check the moisture in the topsoil before you water your cactus again.  

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Final Thoughts – Invest in Fish Fertilizer Now!

If your cactus is growing slower than you expected, is losing its deep green color, or has not grown any new limbs in a long time, use a nitrogen-rich fish emulsion to fertilize it and boost its immunity and growth. If you cannot find high-quality fish fertilizer in the market, you can always prepare it at home.

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