Do I need to cycle tank before adding plants?

Most hobbyists are well aware of how vital it is to cycle a new tank before adding fishes, but when it comes to the question of adding plants, many hobbyist lack the same level of awareness and understanding.  In this post we will discuss the importance of cycling tank before adding plants.

The Short Answer

To put it simply, cycling a new aquarium should always be the first step when it comes to a new tank. This is irrespective of whether you will add plants or fishes. Having said that, it is possible to add very hardy plants in an uncycled tank but your choice of plants will be limited.

Will Adding Plants Cycle The Tank Faster?

In aquarium hobby, many believe that adding live plants to an uncycled aquarium will help to speed the cycling process. However, this is a misconception. If anything, the presence of plants during the cycling of tank, will hamper the establishment of bacterial colonies.

This leads to unwanted issues that we will point out shortly.

Uncycled Tank – It’s Effect On Plants

In a completely uncycled tank, ammonia level is unchecked. Ammonia is highly toxic and can kill fish in a matter of hours, however, their effect on plants can take longer. This is what lulls most people into a sense of false security. Ammonia basically kills off cells exposed to it. Very hardy plants like the different types of Anubias’ can withstand as they have a tough protective layer. More delicate plants, however, cannot stand up to the onslaught of ammonia – will either die off or will show very stunted growth. Thus, only the hardiest of plants will survive in an uncycled tank but their growth will be impeded by ammonia.

Then there are those tanks that are only partially cycled. This is where only the initial colony of beneficial bacteria has been established. What happens here is that ammonia gets converted into nitrites. Many people wrongly assume that nitrites are beneficial to plants and thus plants can be added to a partially cycled tank. This is again a misconception, possibly because nitrites are confused with nitrates. Research has shown that higher plants including most aquarium plants are negatively affected by nitrites.

While the effect of nitrites aren’t as immediate or drastic as ammonia, it still has long-lasting effects. The presence of excessive amounts of nitrites can cause leaf rot, inadequate growth of roots, and make plants susceptible to diseases. Even those plants that can tolerate nitrites, can only do so if adequate amounts of nitrates are present in water. But this can pose problems if you are setting up a low-tech tank or if you have fishes that don’t dwell in abundance of nitrates.

That brings us to a properly cycled tank. In such aquarium, colonies of good bacteria convert ammonia into nitrite and then into nitrates. Nitrates are very beneficial to plants. Plants use nitrates as fertilizers. That is why in a planted tank, you can go for extended period of time without water change if it is properly cycled and balanced with right number of plants and fishes.

Since nitrates are the only form of nitrogen produced during the nitrogen cycle that is actually beneficial to plants, it is best to wait until the tank has been properly cycled.

Dreaded Algae Bloom

Another ill-effect of adding live plants to an uncycled tank is that it can lead to uncontrolled algae growth. While most algae are harmless, they can render aquarium highly unaesthetic. Unless you want your aquarium to look like it has been filled with swamp water, you do not want an algae bloom. Such a bloom, once it occurs, can be quite difficult to remedy.

So, why adding plants to an uncycled tank causes algae bloom?

It involves a lot of complicated processes but to put it simply, algae thrive when there is a chemical imbalance in the aquatic ecosystem. When live plants are added to a tank that isn’t properly cycled, all the life processes that plants have to undertake to stay alive will create chemical imbalances  – this triggers algae growth.

In extreme cases, algae bloom can be so critical that it can prevent light from reaching the plants. This can quickly put an end to your hopes of having a thriving aquascape.

Avoid Experimentation During The Critical Initial Period

Any ecosystem is a delicate balancing act, it is particularly vulnerable during it’s initial days and that is no different when it comes to an aquarium. It needs every bit of help and no disruptions during this stage. Even if you add very hardy plants in an uncycled tank, you are adding an unknown variable into the mix and while the plants themselves may survive the ordeal, it can have highly negative effects on the tank itself.

To Sum It Up

If you have been planning to keep a planted tank then it is quite understandable that you will be eager to add plants to the tank as quickly as possible. However, it is best to show some restraint and wait for two to three weeks needed for tank to be properly cycled. This way, your plants will have a much better chance of surviving and thriving. You will have a wider range of plants to choose from to make your planted tank as spectacular as you possibly can.