Bonsai Tonight

Feed me!

Posted in Bonsai Development by Jonas Dupuich on March 13, 2015

What’s wrong with this picture?

Cork bark black pine

Cork bark black pine

The tree is growing, but there is no sign of fertilizer.

Cork bark black pine

With tea bags filled with cottonseed meal

That’s better. The sooner I can start fertilizing, the stronger I can make the tree by decandling time.

I enjoy seeing the male flowers on pine, despite the mess. Here is the tree from the back and sides.

Cork bark black pine

Left side

Cork bark black pine


Cork bark black pine

Right side

I usually start with 1-2 units of fertilizer for small sized trees and 3-4 units for larger trees. I treat young and middle-aged trees the same.

Black pine

11 year-old black pine

Black pine

21 year-old black pine

While it’s more common to hold off on fertilizing deciduous varieties to avoid long internodes and large leaves, I make some exceptions.

Japanese plum

Japanese plum

My plum is the first tree to show signs of growth each year, and if I don’t start feeding quickly, the leaves turn yellow.

Why mention fertilizer so early in the season? Because the sooner fertilizing begins, the more vigor can be produced in a given year. While this can be important for all varieties, it’s especially important for pines that are to be decandled as there’s only so much time between repotting and decandling.

I usually wait three weeks after repotting to begin fertilizing. My standard fertilizers are fish emulsion and cottonseed meal, but this year I’m planning to use a greater variety of fertilizers to ensure the trees get a broader variety of nutrients.

Is it time to start fertilizing in your garden?

Fall is for fertilizer

Posted in Bonsai Development by Jonas Dupuich on September 23, 2014

A few weeks ago I was struck by yellow foliage on a number of my young pines. After thinking about it for a moment, I came to the conclusion that I hadn’t been fertilizing enough. Black pines in development require a lot of fertilizer. If they don’t receive enough food they can quickly turn yellow. Fortunately the solution is simple – feed more! I began feeding my trees more frequently – about twice a week with fish emulsion – and applied chelated iron to help the trees green up. As you can see below, some of the trees greened up more quickly than others.


The tree on the left is still a bit yellow – both trees receive full sun

Feeding this time of year is important for all varieties as it’s the last chance trees get to increase their strength before winter. This is especially important for trees that we may not feed as heavily in the spring like white pines or deciduous varieties.

Depending on the weather, some varieties will continue to grow into December where I live. Others are already slowing down. I’ll continue to feed the trees that are active and slow the feeding schedule as the weather cools.

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New bonsai fertilizer

Posted in Bonsai Development by Jonas Dupuich on April 26, 2013

Every year I experiment a bit with fertilizer and every year I seem to keep returning to my standard duo – cottonseed meal and fish emulsion. Although they’ve worked well for my trees, I’d like to try a more balanced mix this year. The fish emulsion I use is rated 4-1-1, the cottonseed meal, 6-2-1 – neither providing much phosphoric acid or potash. Boon has used Phyta-Grow brand fertilizer from California Organic Fertilizers, Inc. for years so I thought I’d give it a try this year. We’re using a 50-50 mix of the Pre-Plant PlusTM (7-5-7) and the Veggie MixTM (8-5-0.5) for a combined 7.5-5-3.75.


Equal parts Pre-Plant PlusTM and Veggie MixTM

As I’ve done with the cottonseed meal in the past, I filled tea bags with the fertilizer and held the bags in place with toothpicks.

Tea bags and toothpicks

Toothpicks and tea bags

Filling the bag

Filling a bag

Fertilizer bag

Folding it shut

My primary obstacle to using more balanced fertilizers in the past has been the critters that run off with the bags in the night. They tend to leave cottonseed meal-filled bags alone, but whenever I place anything more interesting inside, they don’t seem to last more than a few days before vanishing. Just a week after trying this new mix, the first few bags have already been torn up, but I’ll wait and see how the rest of the lot fares before switching back to cottonseed meal alone.

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Bonsai fertilizer – follow-up

Posted in Bonsai Development by Jonas Dupuich on May 1, 2012

Last month I began using tea bags filled with fertilizer to feed my bonsai. Unfortunately, it only took a few days for me to realize that this technique didn’t work well as implemented. The bags started disappearing immediately. Critters tore through some of the bags and carried others away completely, leaving behind the toothpicks that were meant to keep the bags in place. Somehow they removed all of the bags from my best trees and only a few of the bags on the developing trees – I won’t even try to solve that one. Instead, I’ll go back to my time-tested fertilizer method – clumps of cottonseed meal and fish emulsion.

Tea bags on a pine forest

Tea bags intact on a pine forest

Tea bags on an exposed root pine

Tea bags on an exposed root pine

Cottonseed meal on a pine

Cottonseed meal on a pine

Cottonseed meal on a pine

More cottonseed meal

I usually start feeding my trees at some point between late January and mid March depending on the weather and the variety. If I’ve repotted a tree, I wait about 4 weeks before feeding it. I start by placing one or two clumps of cottonseed meal and add additional clumps every 1-3 weeks later until the majority of the pot is filled with fertilizer.

Cottonseed meal on a cryptomeria

Cottonseed meal feeding a recently separated cryptomeria

I supplement the cottonseed meal with fish emulsion (see “Bonsai Fertilizer” for details). Fish emulsion is a great, if stinky, fertilizer that I’m comfortable using on all bonsai varieties. I usually apply fish emulsion weekly, though I might apply it more or less frequently at various times depending on the season, the weather and the variety.

Fish emulsion

Fish emulsion

Ebihara fed his trees with diluted liquid fertilizer every three days (I don’t know what type of fertilizer he used). Others primarily rely on dry fertilizer that releases food whenever the trees are watered. I haven’t noticed big differences between liquid, dry, or other categories of fertilizer, but I do find that consistent application leads to the best results. And the best results, of course, depend on the goal of the fertilizing program. If I’m trying to increase the size of the trunk, I fertilize a lot. If I’m trying to ramify delicate branches on deciduous varieties, I fertilize very lightly and only after new leaves have hardened off.

As for the tea bags, I haven’t completely given up. I may yet try chili powder or some other caustic agent that’s harmful to vermin but safe for trees. And if I can get this right, I will celebrate and then post the results.

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