A bonsai tree may be small, but it still needs the same essential nutrients as a full-sized tree. Because bonsai grow in shallow pots with limited soil, nutrients are quickly used up or washed away during watering. Regular feeding is therefore essential to keep your bonsai healthy, vibrant, and growing well.
In this guide we’ll explain how fertiliser works, what NPK values mean, and how to feed your bonsai correctly using a liquid bonsai fertiliser.
Why Bonsai Trees Need Fertiliser
In nature, trees have access to a huge network of roots spreading through nutrient-rich soil. Bonsai trees, however, are grown in small containers with free-draining soil mixes. While this soil is perfect for healthy root growth, it contains very little natural nutrition.
As you water your bonsai, nutrients gradually wash out of the pot. This is why regular feeding is important — fertiliser replaces the nutrients that the tree needs to grow leaves, strengthen roots, and maintain overall health.
Liquid fertilisers are particularly useful for bonsai because they provide nutrients quickly and can be easily absorbed through the roots.
Understanding NPK Values
Every fertiliser has an NPK ratio, which represents the three primary nutrients plants need. These numbers indicate the percentage of each nutrient in the fertiliser.
N – Nitrogen
Promotes leafy growth and lush green foliage. Nitrogen is especially important during the growing season when bonsai produce new shoots.
P – Phosphorus
Supports strong root development, flowering, and fruit production. This nutrient is particularly useful for newly repotted trees or species that flower.
K – Potassium
Improves overall plant health, strengthening the tree’s resistance to stress, disease, and temperature changes.
Our liquid bonsai fertiliser is formulated with an NPK ratio of 1.9 : 0.7 : 3.9 to support balanced, controlled growth in bonsai trees. Bonsai are grown in small containers where excessive nitrogen can quickly lead to overly vigorous growth with long shoots and large leaves, which can spoil the refined proportions of the tree. By keeping nitrogen at a moderate level, this formula encourages healthy foliage without pushing excessive growth. The lower phosphorus level supports steady root development without leading to leggy growth, which is not necessary for many bonsai species. The higher potassium content helps strengthen the tree overall, improving resilience, root health, and resistance to stress from pruning, wiring, repotting, and changing weather conditions. This balanced approach makes it ideal for regular weekly feeding while maintaining the compact, controlled growth that bonsai cultivation requires.
Types of Bonsai Fertiliser
There are two main types of fertiliser commonly used for bonsai:
Liquid Fertiliser
Liquid fertiliser is diluted with water and applied when watering your tree. It is absorbed quickly and allows for precise feeding.
Benefits include:
- Fast nutrient uptake
- Easy to control dosage
- Ideal for regular feeding schedules
Liquid fertilisers are commonly applied weekly or every two weeks during the growing season. (Miyagi Bonsai)
Slow-Release Fertiliser
Slow-release fertilisers come as pellets, granules, or cakes placed on the soil surface. Each time you water your bonsai, nutrients slowly dissolve and feed the tree over time. These are typically applied a few times per season rather than weekly.
How Often Should You Feed a Bonsai?
Most bonsai benefit from regular feeding during the active growing season (spring to early autumn). Liquid fertilisers are commonly used weekly during this period to provide a consistent supply of nutrients.
In winter, many bonsai species enter a dormant phase and require little or no fertiliser.
Feeding Your Bonsai with Liquid Bonsai Fertiliser
Using a liquid fertiliser is simple and ensures your bonsai receives the nutrients it needs without overfeeding.
Weekly Feeding Method
- Prepare the solution
Mix the recommended amount of liquid bonsai fertiliser with water. - Make a 1 litre batch
A simple feeding mix is:- 1 litre of water
- The recommended dose of liquid bonsai fertiliser
- Water your bonsai
Pour the solution evenly over the soil until water begins to drain from the bottom of the pot. - Repeat once per week
Feed your bonsai once a week during the growing season for steady, healthy growth.
If you only have one small bonsai, you can also mix a smaller amount of solution — just enough to water your tree thoroughly.
Tips for Safe Bonsai Feeding
- Never fertilise dry soil. Water your bonsai lightly first if the soil is completely dry.
- Avoid overfeeding. Too much fertiliser can damage roots or cause excessive growth.
- Adjust feeding for the season. Reduce or stop feeding during winter dormancy.
- Follow product instructions. Always use the recommended dilution.
Healthy Feeding for a Healthy Bonsai
Consistent feeding is one of the most important parts of bonsai care. By understanding NPK values and applying fertiliser regularly, you give your tree the nutrients it needs to stay strong and beautiful.
A simple weekly routine using a liquid bonsai fertiliser ensures your bonsai receives balanced nutrition, encouraging healthy roots, vibrant foliage, and steady development throughout the growing season.
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