“The Bonsai Gas Pedal: Revving with Purpose”

In an enlightening post “Fertilization & Bonsai”, one of the world's leading specialists in the practice of Bonsai, Ryan Neil skilfully reframes fertiliser not as mere sustenance—but as the “gas pedal” of bonsai development. He urges us to pause and ask: “What am I trying to accomplish?” A tree's design goals, health, growth stage, and seasonal context should guide how, when, and how much we fertilise. The nutrient boost, explained as supplemental rather than essential, when thoughtfully applied, energises roots, encourages back-budding, thickens branches, and supports healing—though always best paired with active foliar management.

Who is Ryan Neil?

Ryan Neil is an American bonsai professional and founder of Bonsai Mirai, a world-renowned bonsai garden, school, and digital learning platform. Trained in Japan under master Masahiko Kimura, Neil has become a leading voice in Western bonsai, particularly emphasising horticultural science and tree health as the foundation for artistic design. In the field of bonsai nutrition, he is known for advocating a data-driven, tree-specific approach—encouraging growers to view fertiliser not just as “food” but as a way to influence growth patterns, recovery, and long-term resilience.

Image: A paper teabag used to hold solid fertiliser pellets - Courtesy of Bonsai Mirai

What Can We Learn?

As someone who’s both captivated by and occasionally bewildered by the intricacies of these ancient organisms (existing in tiny pots), I found this metaphor of the gas pedal (accelerator) brilliantly clarifying. It’s a welcome departure from the “one-size-fits-all” fertiliser advice that often graces bonsai learning guides. Instead, Neil's approach encourages mindfulness and adaptability, planting the notion that fertilisation isn't a formula to follow, but a tool to be wielded with intent.

The big take away, is that fertilisation is extremely nuanced, tree specific, geography specific, and altogether dependent on development stage.

“What am I trying to accomplish?” 

Anyone familiar with Mirai's learning platform will know that the level of detail on any one topic can only be hinted at in written format - and tree nutrition is one of these topics. For instance, practical guidance like choosing between organic versus chemical options, or pointers on post-repot fertilising strategies, can be pulled apart and thoroughly investigated in video content, podcasts and live talks given by Neil. These rich sources of insights from forums and live presentations suggest there's a lot of subtlety behind each choice—for example, delaying fertilisation after a repot until new growth appears is advised by seasoned practitioners, and the choice between Bio-Gold and Osmocote hinges on cost, residue, and microbial impact.

Image: Courtesy of Bonsai Mirai

Exploring the New Era of Nutrition

Recent developments also deepen our understanding of fertilisation’s role. For instance, Bonsai Mirai’s own experimentation with soil science expert David Knaus and Apical AG has unveiled that many bonsai suffer from nutrient imbalances—particularly calcium deficiencies—despite appearing outwardly healthy. This sort of data-driven, diagnostic approach emphasises that fertilisation isn’t just about growth—it’s about balance and long-term resilience.

Mirai's Message & Future Directions

Fertiliser should serve the tree’s goals, not drive a rigid schedule. Still, I hope future writing from Bonsai Mirai and bonsai and science peers explores:

• Personalisation through testing: Could nutrient profiling become more accessible? If calcium is almost universally deficient, as suggested in Mirai's article, this may be a worthwhile starting point for many growers.

• Fertiliser formats & micro-management: From cakes and tea bags to liquid feeds, each method has trade-offs. Real-world accounts, such as those describing the pros and cons of Bio-Gold versus Osmocote, could guide practical decision-making.

• Recovery periods post-work: Further advice on fertilising after repotting, major wiring, or even winter dormancy, would help practitioners fine-tune their approach to seasonal stresses.

• Holistic tree health strategies: Integrating insights on watering cycles, soil composition, and microbial life (e.g., how fertiliser interacts with pumice or akadama substrates) would make fertilisation advice feel more of a refined part of overall horticultural care.

If you enjoyed finding out how Bonsai Mirai’s blog peeled back the layers of fertilisation philosophy with clarity and elegance, you can find more information on our website via REND.