Bonsai Tonight

An educational website about bonsai development

Options for applying bonsai fertilizer

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I’ve been enjoying experimenting with the new fertilizers I’m using this summer. Ten days ago I applied Omakase fertilizer cakes to a number of my trees and I’ve already noticed a few things.

One of my concerns had been whether or not the cakes would break down quickly as the cakes are very hard out of the bag. Just yesterday, however, I noticed that some of the larger cakes had already started to break apart.

The fertilizer cake on the left is starting to crumble

The intact cakes have softened considerably which tells me that water is having no trouble penetrating the cakes.

Because I wasn’t sure, initially, how well water would penetrate the cakes, I tried a few approaches to keeping them moist. On one tree, I buried cakes at varying depths.

Fertilizer cakes on top of the soil (left) and nestled into the soil (right)

While the cakes placed on top of the soil have taken on a lighter color than the cakes that are partly buried, all have softened about the same.

I’ve also tried pre-crumbling the cakes.

Smashing a fertilizer cakes

I then added the crumbled bits directly to the surface of the soil on several trees.

Crumbled bits of fertilizer on the surface of the soil

One of my bigger challenges with bonsai fertilizer over the years has been critters running off with it. I’ve been happy to note that to date the cakes have remained where I left them. Omakase fertilizer is designed to be less interesting to critters than other fertilizers, and so far I’ve found that to be the case.

For a more direct comparison, I’m also testing the fertilizer in tea bags, both crushed and uncrushed.

Crushed fertilizer cakes in teabag

Intact cakes in teabag

Garden critters – mostly squirrels and raccoons, as far as I can tell – have been picking up fertilizer bags filled with cottonseed meal recently and dropping them on the ground here and there. Today I put out more bags with fertilizer cakes inside to see whether or not they stay put.

Omakase fertilizer in teabags

I’ll be increasing the amount of fertilizer used in the garden over the coming weeks as it’s time to start feeding decandled pines so I expect this to be a good opportunity to see what happens with the different approaches to feeding.

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Comments

  1. Jonus
    What is your take on fertilizing in extremely hot weather? Here in El Dorado Hills [Sacramento] it has been well over 100 degrees for the past few weeks.
    Thanks, Mike

  2. Good question Michael. I don’t expect problems when using low nitrogen organic fertilizers, especially when they are diluted properly. I would, however, avoid using fertilizers that become more potent as temperatures rise. My understanding is that some pelleted or time release fertilizers like Osmocote actually release more food as the temperature heats up – exactly the behavior you want to avoid.

    It’d be great to hear from people in hot climates – any tips for us?

  3. Excuse the noob question – only been collecting a year – but did you buy the teabags or make them? If so, how?

    They look like they’d suit my trees regime. Thanks

  6. I haven’t seen anything on Alaska All Purpose Dry Fertilizer, do you have any experience with it?

  8. Jonas,

    When will you start to reduce nitrogen for fall. I have read that a few weeks after summer solstice is around the time to start switching to fall fertilizer. Is that right? How/ when do you make the switch? This will be my first fall in bonsai so not sure how/ when to make the switch. My guess is that in 2-3 weeks, is that about right? Do you recommend any specific fall/winter fertilizers?

    Sorry for so many questions in one post

    Thanks!

    • Very good questions about fertilizer. My starting point for addressing fertilizer questions is to consider why I’m fertilizing in the first place. For decandled pines, I’m adding more and more fertilizer these days. I’m also starting to feed deciduous bonsai more. In many instances, fall is when I feed more trees in the garden than any other time of year as I want the trees to be strong through winter and strong in spring.

      How you feed your trees will depend on the immediate goals for them. If you are developing the trunk, continue feeding heavily. If the trees are developed, feed moderately until the trees shut down for winter. And if you have more specific questions, try a local bonsai club or a forum like http://ask.bonsaitonight.com