How to Cycle Aquarium with Plants

One major thing to achieve while setting up an aquarium is to make it safe, healthy, and habitable for fish and other aquatic critters — and this is possible only through cycling.

Aquarium cycling entails the series of actions involved in making the aquarium ecosystem safe and non-toxic for aquarium fauna by establishing an active biological filter to break down and convert the harmful nitrogen compounds present in the aquarium.

This way, the waste produced by animals, plus other sources like decaying leaf litter, fish food, detritus, etc. can be oxidized to less toxic compounds, thus making the environment safer for the aquarium inhabitants.

There are several methods to cycle a fish tank; however, this article concentrates on the cycling of a tank with live aquarium plants.

Cycling An Aquarium With Live Plants

Apart from the popular fish-in cycling or fishless cycling methods which appear to be the most commonly used method by both beginner and experienced aquarists, another common method is fishless cycling or ‘cycling with live plants’.

Lately, more aquarists are adopting this cycling method because it helps to establish a healthy, natural ecosystem for various aquatic lifeforms, and at the same time, it averts the exposure of fish to lethal toxins during cycling.

So instead of setting up a bare tank with little bioload, one can introduce a variety of live plants and nurture them with the aid of a nutrient-rich substrate, good lighting, and fertilizers.

The objective here is to grow live plants to consume the nitrogenous waste (ammonia and nitrates) and also to establish a healthy colony of beneficial bacteria in the aquarium.

Main Difference of Cycling an Aquarium With Live Plants

As we all know the nitrogen cycle is THE MOST important process in the aquarium. It refers to the establishment of beneficial bacterial colonies.

These beneficial bacteria are used to break down harmful waste (ammonia) into a less toxic form, first to nitrites and then down to nitrates. The cycle is done then there are no ammonia and nitrites.

To make the comparison clear I need to remind how the fishless cycle looks like:

1. We start adding pure ammonia to the tank. It should not exceed 4-5 ppm.
2. After some time we get an Ammonia spike.
3. At this point, we have to wait until the ammonia level drops to around 1 ppm. It may take from a few days to a few weeks.
4. When ammonia becomes lower when 1 ppm, we increase it to 2 ppm again.
5. We keep adding ammonia until it only takes 1 day for the ammonia to drop from 1-2 ppm to zero. Basically, it shows us that we have enough Ammonia Oxidizing Bacteria to control the ammonia.
6. We keep adding ammonia to create enough Nitrite Oxidizing Bacteria to effectively convert the nitrites into nitrates. We can see these changes after the Nitrite spike.
7. Once we see nitrates it means that the colony of Nitrite Oxidizing Bacteria is growing and the cycling is about to finish.

However, the main difference between fishless cycling and cycling an aquarium with live plants is that you will not see ammonia, nitrite, and nitrate spikes because plants will use nitrogen for their growth.

For plants, nitrogen compounds like ammonia and nitrates are food sources. Depending on the plant type, they absorb nitrogen through their leaves and/or root systems.

That is why there should not be any ammonia spike. Instead, you will see new leaves and growth.

It is almost like you are completely skipping the process of converting ammonia to nitrites and nitrites to nitrates.

Important: I am saying ‘almost’ because plants cannot completely replace beneficial bacteria. No, it means that at this current period of time, they have a leading role in maintaining balance in the aquarium.

Eventually, beneficial bacteria will grow anyway but it will happen naturally without any ammonia and nitrite spikes.

Plants Requirement for Cycling Tank

A candid advice at this juncture is to opt for fast-growing plants.

The point being that live plants require a lot of nutrients to keep up with their fast growth habits. As I have already said, live plants use up ammonia, nitrites, and nitrates for their growth.

Although these nitrogen compounds are lethal to fish and sensitive inverts like shrimp, they (ammonia and nitrates) nourish aquarium plants and help them attain luxuriant and vigorous growth.

Thus, cultivating live plants with fast growth capabilities in your fish tank will effectively help cycle it quicker than slow-growing plants. For this reason, endeavor to pick fast-growing live plants for your fish tank’s cycling.

It doesn’t end there, you also need to consider the attributes of the live plants.

In this case, since the aquarium is yet to cycle — you don’t need plants that cannot thrive in non-optimal conditions.

Avoid delicate plants and tissue-cultured plants, and opt for plants that are quite hardy, else they may melt in the new tank due to pH fluctuations, the presence of a high level of ammonia, and other organic contaminants during the course of cycling.

Plants Recommendations

All plants can be divided into 2 main categories:

1. Water column feeders (mostly floaters).
2. Root feeders.

Water column feeders get most of their nutrients from the water. Whereas root feeders obtain their nutrients from the substrate.

Why is it important to know during cycling the tank?

Out of these two types, floating plants are the most efficient ammonia and nitrate-suckers. Besides, these plants also have an excess of CO2 and receive more light. As a result, they have been duly observed to exhibit immense growth rates within short periods.

Therefore, to get optimal results, it is better to choose water column feeders as the main ones and root feeders as secondary ones (they will play a support role to maintain the system stable and safe).

Example of floating plants for cycling:

• Duckweed,
• Hornwort,
• Water Wisteria,
• Frogbit,
• Water Sprite, 
• Dwarf Water Lettuce,
• Fairy moss,
• Water hyacinth,
• Brazilian pennywort,
• Pothos plants.

Examples of fast-growing root feeder plants for cycling:

• Anacharis,
• Red Tiger Lotus,
• Vallisneria. 

Factors That Can Influence Growth of Live Plants

Fertilizers:

Aquarium plant fertilizer plays a crucial role in the growth of live aquarium plants. It supplements the amount of nutrients available in the fish tank, makes your live plants grow healthy and fast; and thus, hastens the cycling of the tank.

Aquarium fertilizers are available in two common forms:

1. liquid fertilizers (for column feeders)
2. root tabs (for heavy root feeders).

The liquid plant fertilizers are dosed directly into the water column whereas the other variant is meant to be buried into the substrate bed.

Both fertilizers are ideal for enriching the aquarium by adding essential nutrients into the aquarium water or aquarium substrate. And the live aquarium plants have to draw up these nutrients to fuel their growth and spread profusely in the tank.

Good Lighting:

If you want to cycle a fish tank with live aquarium plants, then you need to provide enough illumination to spur their growth.

Lighting is highly important in the life of aquarium plants because they need ample lighting to carry out photosynthesis on a daily basis for their overall nourishment.

That said, make sure to obtain an aquarium light that can cater for the lighting needs of your live plants. The chosen aquarium light should have the ideal color spectrum and intensity to support growth of the live plants during and after cycling.

Aquarium LED lights are quite popular in the hobby owing to their efficiency and durability, so you may want to acquire one for your fish tank. While shopping, look for a model with a dedicated aquarium timer to allow for maximum control of the photoperiod.

Read more about it in my article “Advanced Guide to Planted Tank Lighting”.

Substrate:

Substrate is crucial for the root feeders. It doesn’t matter for floating plants since they grow on the surface of the water.

Note: Substrate also plays an important role in establishing beneficial bacteria. Beneficial bacteria attach themselves to any surfaces throughout the aquarium. So, after filter media, substrate ranks second beneficial bacteria content.

For root feeders, aquarium substrate provides an ideal medium for attachment of your plants’ roots, and it also holds nutrients which the plants can absorb for their growth.

Therefore, to grow this type of plants, you will need a good substrate, this can either be enriched aquasoils or plain substrates. Good examples include Caribsea Eco-Complete, Fluval Stratum, and ADA Amazonia.

Most live aquarium plants have preferred substrate choices, so ensure you find out the one that works best for your chosen plants and act accordingly.

Read more about it in my article “Top 5 Substrates For Planted Aquariums”. 

Optimal Temperature:

A large percentage of live aquarium plants require a warm temperature to thrive in an aquarium. In addition, the warmer water boosts beneficial bacteria growth and, as a result, will speed the cycle.

Hence, be sure to place an aquarium heater in the tank to regulate the water temperature.

Also, avoid practices that may cause the aquarium water temperature to change drastically within a short period of time, or the plants may melt.

Getting Started

You will need to set up your aquarium with the necessary equipment and items.

Before cycling an aquarium with live plants, you need to set up your aquarium with the necessary equipment and items. By this, I mean:

• mounting the tank,
• placing the filter,
• adjusting the water temperature (placing the heater if necessary),
• adding substrate,
• adding dechlorinated freshwater,
• buying fertilizers (containing nitrogen),
• buying the test kit.

How to Cycle An Aquarium With Live Plants

The initial set-up is done, it’s now time to add the live plants and cycle the tank.

To do this, follow the steps outlined below:

1. Gather the live plants and disinfect them first to get rid of all harmful microbes, parasites, and snails that they may be carrying.
   Note: Unless you are completely sure that the plant is safe, you can skip this step. Moreover, these plants will already have beneficial bacteria on the leaves. It will also help you with cycling the tank.
2. After proper disinfection, add the live plants to your tank.
3. Next, set up the aquarium lighting (10-12 hours per day).
4. Add the aquarium plant fertilizer to the tank.
   For column feeders, you can use liquid plant fertilizers, but if it’s root feeders — add root tabs in the substrate bed to supply nutrients to their extensive roots.
5. At this point, you need to wait at least 2 – 3 weeks to witness new growth on your live plants.
6. Once you start seeing a lot of new growth, it’s very likely that your tank is reaching balance.
   Note: Besides plants growth, your tank may have lots of green algae, brown algae (diatoms), etc. everywhere DO NOT worry. On the contrary, this is a very good sign; it means that there is enough nutrition to sustain growth.
7. Lower your lighting to 8-10 hours, if you have too much algae.
8. Start testing your water parameters. Wait a few more weeks to make sure that the tank is stable.
9. To confirm that your planted tank has actually cycled, you can add a few drops of pure liquid ammonia, around 1 ppm (no more), in your tank and wait for 24 hours.
   Test your aquarium water after the 24-hour interval and observe the readings.

Adding Animals

A cycled tank should have undetectable levels of ammonia and nitrite, so if the test shows zero ppms of ammonia and nitrite and little to no nitrates — you can infer that your tank has fully cycled. Only then can you add animals into the tank (after quarantining it of course).

Be careful with shrimp: DO NOT rush to add dwarf shrimp to the tank. The main problem with shrimp is that many species are pretty sensitive to any changes. In addition, they require a matured tank to thrive.

Wait a few more weeks, let the tank develop a stable eco-system with biofilm and algae as a natural source of food for your shrimp.

Boosting the Cycling Process

Also, there is actually a way to quicken cycling while using live plants, and that is through the addition of bacteria starter into the fish tank.

That not only decreases the waiting period but ensures that a huge population of beneficial bacteria is produced.

Some recommended products (links to Amazon):

• Tim’s Aquatics Ammonium Chloride Aquarium Treatment for Fishless Cycling
• API Quick Start Nitrifying Bacteria
• Tetra SafeStart Plus To Cycle New Aquariums
• Fluval Biological Enhancer for Aquarium

Caution:

• Overstocking

Avoid adding too many animals into the tank after the process has come to an end. Especially, large fish species, snails, large crabs, and crayfish, etc., – these animals produce a lot of waste!

It can cause a mini-cycle (also known as a New tank syndrome). Mini-cycle is the result of an insufficient amount of plants and/or beneficial bacteria compared to the existing bioload in the tank.

Overstocking is counterproductive since it can cause the tank to cycle again. More fish translates to an increased release of toxic waste, so it’s best to have a few fish at this point.

• Feeding

Endeavor to feed your fish sparingly; you can feed them just once a day or two to prevent ammonia spikes.

Do this consistently for two to three weeks and switch to feeding them once or twice a day. In addition, be sure to test the aquarium water regularly, and if there is any change in the ammonia and nitrite levels, revert to feeding them once daily.

• Quarantine

Since new aquarium fish can introduce harmful microbes and parasites into your fish tank, make sure to keep them in a quarantine tank for a week or more, and treat them with medications to tackle any sort of infections.

• Cleaning

Also, remove dead leaves as soon as you spot them because these can decompose and release additional ammonia in your aquarium.
It should not be a problem at later stages than the tank is cycled or close to be cycled but in the beginning, this is an unnecessary source of nitrogen.

• Water Testing

Do not disregard the need for steady water testing. Make sure to test the aquarium water regularly to monitor changes in the ammonia, nitrite, and nitrate levels.

Pros and Cons of Cycling An Aquarium With Live Plants

Cons:

1. It is not instant. Generally, it can take a few weeks before you see plants’ growth and nitrogen control.
2. Plants can melt and die off. Obviously, it is not possible to control ammonia and nitrates without plants.
3. Lots of plants. The number of plants should correspond to the nitrogen.
4. Can’t control the cycling process. Nobody can tell you how long and how many plants you will not need to process this or that amount of ammonia.

Pros:

1. Natural. Cycling with plants is probably the most natural way of cycling. On a large scale, plants are used to remove nitrogen in sewage facilities.
2. Beautiful. You can décor your tank right from the beginning.
3. Easy. Unlike fish-in cycling or fishless cycling, there is no need to add and measure ammonia, nitrites, and nitrates all the time.
4. Stable. Besides plants that consume ammonia in the first place, eventually, you will also have beneficial bacteria growth. As a result, in the long run, plants and beneficial bacteria will create an excellent balance and a perfect substitution mechanism in the tank.

In Conclusion

Cycling an aquarium with live aquarium plants is a simple and straightforward process that every aquarium owner should be able to execute.

With this method, our tanks can be easily made safe and suitable for habitation before the addition of aquarium fish and inverts.

Although this is not a fast process; it has lots of other benefits.

Related articles:

• How to Cycle a Tank: the Dark Start Method
• Step-by-Step Cycling your Shrimp Aquarium Fishless