Do Bonsai Need Fertilizer? Here is How To Fertilize Your Bonsai Tree

Fertilization of a bonsai tree is one of the most important questions about bonsai gardening. So, today I will discuss bonsai fertilization. Does a bonsai tree need fertilization from outside? Is the soil in the pot is enough for a bonsai to survive?

Do Bonsai Need Fertilizer?

One of the basic differences between a normal tree in nature and a bonsai is that a bonsai is confined in a pot. So a bonsai it can not reach out to nutrients other than that are present in the pot.

After some time the nutrients present in the potting soil will finish. So yes you need to fertilize your bonsai trees to replenish the lost nutrients in the soil.

Also whenever you water the bonsai some of the nutrients will drain out along with the water.

Though we prune a bonsai tree regularly to keep them small and limit its nutrients need to the bare minimum we have to add fertilizers to keep them growing vigorously or simply to keep them alive.

What Plants Need For Growing:

Plants need a variety of minerals and elements to complete their nutrition. Most importantly carbon, oxygen, hydrogen they receive from air and water. Other than these they also need nitrogen, phosphorous, potassium.

These three they get from the soil in the form of nitrate, phosphate and potassium salts. There are also many trace elements, that are important for the growth of the plant and present in the soil.

Whenever you prepare or buy bonsai soil, it will be enriched with these elements. But with constant use, it will end pretty fast. So you have to fertilize your bonsai plant from time to time with good quality bonsai fertilizers.

Whenever you choose a bonsai fertilizer, make sure it has the perfect balance of essential nutrient components. Generally, when you buy a fertilizer they mention the ratio of nitrogen phosphorous and potassium and other trace elements in the label.

Now, not every time you will find the exact match of what you are looking for your bonsai. In that case, you have to mix different fertilizer to get to your optimum ratio.

What is the ideal N-P-K ratio in bonsai fertilizer:

the ideal NPK ratio of any fertilizer varies depending on the stage of the plant or the season. In most cases, an equal ratio of NPK is good for the bonsai.

In some cases like in the time of the Spring or when the bonsai is in the training phase a fertilizer that is high in nitrogen (for example 25:15:15) is better for the plant.

On the other hand in late summers till dormancy, a fertilizer with high phosphorous and low nitrogen is good for the bonsai.

When to Apply Bonsai Fertilizer?

You have to fertilize your bonsai tree regularly especially during the growing season. This also varies from species to species, and age of the bonsai tree.

If the tree is older or not in the growing stage you might have to reduce the frequency of fertilization.

Type of trees also plays a role deciding on when to apply the fertilizer.

For example, if you have a deciduous bonsai tree, during the growing season, fertilize it weekly and stop once the leaves have fallen. During the fall and winter months feed your bonsai with a nitrogen-free bonsai fertilizer.

For conifers, during the growing season, fertilize weekly. In winters fertilize a few times with a nitrogen-free fertilizer.

Any tropical and sub-tropical bonsai grow throughout the year and so fertilize them weekly during the growing season, and monthly from fall to spring.

Start Fertilizing Bonsai After Repotting:

Your first fertilization will start once you repot your bonsai. Alternatively, you can also start the fertilization process after the beginning of the growing season once you see the first leaves.

Here is key, start with lighter versions of bonsai fertilizers and with the commencing of the growing season shift to a more balanced form of fertilizer.

For indoor bonsai trees, you can apply the fertilizer throughout the year. Unlike outdoor bonsai trees, indoor bonsai doesn’t face any seasonality problems they don’t have any dormant stage like outdoor plants. For indoor bonsai plants, a liquid fertilizer is probably the best choice.

How To Apply Bonsai Fertilizers:

Water-Soluble Fertilizers:

If you got water-soluble fertilizers then first mix it with water. Then apply the fertilizer uniformly on the soil surface. Keep adding the fertilizer till the soil cannot absorb any more of it and it starts dripping off the drainage whole.

Solid Fertilizers:

If you use solid fertilizers place it on the soil surface, and water on top of it. This will gradually release the nutrient every time you water your bonsai tree.

The good part about solid fertilizers is you don’t need to fertilizer very frequently, your watering and fertilizing will be done at the same time. You only have to add the solid fertilizer after 2 to 3 months.

Use fertilizer covers to hold the fertilizer in a place and also prevents it from scattering.

What is The Best Fertilizer For Bonsai Trees?

Should I Use Liquid Fertilizer or Slow-Releasing Pallets:

Both Liquid fertilizer and slow-releasing pallets have their pros and cons. If you are a beginner and not very faithful to a fertilizing routine slow-releasing pallets are probably a good choice for you.

You can add fertilizer once and it will supply the nutrients to the plant for a quite some time. The drawback about this is in the growing season the plant needs a lot of nutrients then a slow-releasing fertilizer might not be able to handle the demand.

Liquid fertilizers are good for providing nutrients quickly and for the growing season, it is by far the better option to fertilize. But the problem with liquid fertilizer is there is a lot of waste whenever you water the plant. So you have to replenish the soil in a regular interval.

The best option probably is to go for slow-releasing fertilizer for the entire period of the plant and in the growing season, supplement this with a liquid fertilizer. Whenever you apply liquid fertilizers pour the fertilizer over the leaves and allow it to drip into the soil.

How Often Should You Fertilize Bonsai?

The best way to go about this is to follow the recommended dosage by the manufacturer.

Fertilisers are made for promoting optimum growth levels of a plant. So you should follow the manufacturers recommended dosage to achieve the best NPK level for your bonsai. If nothing is mentioned on the label you can apply the fertilizer twice in a month.

Some Tips For Fertilizing Your Bonsai: 

  • 1. Fertilization is not a one-time act. You should fertilize your bonsai regularly so it continues to produce fantastic growth.
  • 2. before finalizing on the fertilizer check your plant. Every plant has different needs.
  • 3. Don’t fertilize your bonsai when the plant is in the dormant stage. This will only harm your bonsai tree.
  • 4. if your bonsai is not healthy, try to find out the reason behind it. Feeding a sick tree will only harm the plant.