What kind of bonsai fertilizer do you use? – Bonsai Tonight

July 19, 2016 by Jonas Dupuich

I hear the question a lot – “What kind of fertilizer do you use?” The answer is a moving target. So far this year I’ve used various combinations of six different fertilizers.

My go-to fertilizers remain cottonseed meal and fish emulsion. They are affordable and they keep my trees healthy. It’s not the cleanest solution nor does it smell great, but overall the approach works well for me.

Cottonseed meal

I’m also using limited amounts of two fertilizers I’ve used before: Dr. Earth Life pellets – another organic option – and Miracle Gro. I tend to prefer organic fertilizers to inorganic ones, but I know people don’t always have options and I want to have a good idea of how different fertilizers can work for my trees.

Dissolved Life pellets from Dr. Earth

I’m currently experimenting with two additional fertilizers. The first is Sumo Cakes – handmade fertilizer balls with an NPK rating of 4.8-4.8-4.8. Ingredients range from alfalfa meal to zinc sulfate with a variety both plant and animal based nutrients. I received a sample for testing purposes and look forward to learning more.

Sumo Cakes

The second fertilizer I’m experimenting with is from Japan – Tosho brand Omakase pellets, aka OOF (Odorless Organic Fertilizer). As the name OOF suggests, one of its primary good points is that the fertilizer doesn’t have a strong smell – the idea being that insects and animals are less likely to take in interest in it and eat or otherwise steal it away from our trees.

Omakase pellets

I’ve used this fertilizer before but have had trouble finding it so I brought some in from Japan (see Omakase for details). I’m very curious to see how the bonsai like it.

As for how I apply fertilizer, I use liquids through a watering can, apply solid fertilizers directly to the soil, and use tea bags filled with different fertilizers. Each has its good and bad points. I love using liquid fertilizers – they are easy to dilute and fast acting – but feeding a large collection with a watering can can take a long time.

I love the simplicity of dumping mounds of dry fertilizers directly on the surface of the soil, but this can have adverse effects on drainage and looks messy.

Nothing is faster than applying – or cleaning up – tea bags filled with fertilizer, and nothing is slower than filling them up. Not everyone thinks they look good either. But my favorite thing about them is that it’s easy to see at a glance how much food the tree is getting.

Teabags filled with organic fertilizer

Almost every tree in the garden has some sort of dry fertilizer on it – many have two or more – and almost every tree gets liquid fertilizer between one and four times per month. I like it when trees get different fertilizers as it’s a good way to spread the benefits that each fertilizer offers.

Tea bags filled with Dr. Earth Life pellets – mound of cottonseed meal in the foreground

Dango – Omakase pellets – and tea bag filled with cottonseed meal

And so the experiments continue. I hope to learn a few things about bonsai fertilizer this summer, and to find new fertilizers to experiment with next year.

A teabag nestled among exposed roots

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