Bonsai Tonight

An educational website about bonsai development

Bonsai fertilizer

by

I had a strong desire to post the smell of my garden today. I’ve been using more liquid fertilizer than normal this year. The result is that it smells more than normal.

Watering can with liquid fertilizer

There are many options for fertilizing bonsai, and individual varieties – and sometimes specimens – have specific requirements. I tend to rely on lumps of cottonseed meal, but because I’m behind in cleaning the surface of the soil for the trees I didn’t repot, I’m using liquid instead. And because I like using organic fertilizers whenever possible, I use a lot of fish emulsion.

Mmm – fish emulsion! From Encinal Nursery

Why not use dango, the Japanese fertilizer balls? Because the raccoons – or whatever creatures steal dango in the night – find them endlessly fascinating. Using loose clumps of cottonseed meal and liquid fertilizer reduces my interaction with varmints.

Fertilizing with fish emulsion

I imagine some bonsai enthusiasts are very precise in their application of bonsai fertilizer. I’m not. I pour fish emulsion in the bottom of a watering can, add water, and swish it around. I demonstrate more discipline when it comes to how frequently I fertilize. I don’t keep track of dates on the calendar – a clear best practice – but I make sure my trees get plenty of food. Just wish it smelled better sometimes.

Subscribe to Bonsai Tonight

New Posts Delivered Every Tuesday and Friday

We won't send you spam. Unsubscribe at any time. Powered by ConvertKit

Reader Interactions

Comments

  1. Do you use the fish emultion fertilizer for all of your bonsai trees, including Japanese Maples.?

    • I do – I’ve used fish emulsion on all of my trees and with no ill effects. I’ve burned trees with other fertilizers, but not with fish emulsion or cottonseed meal.

  2. Your liquid fish looks dark compared to mine when mixed. How much do you use per 1 gallon of water? I can see not using any fertballs or cakes but I can tell you from my experience the fish emulsion is tempting to them as well. If they smell it on the soil surface they will dig into the soil to find the “fish”. I’ve been having to spray a 50/50 vinegar and water solution in and around my trees and my area where I keep my trees. I do not spray on my trees or the soil. I did however had to spritz a bit on my fert cakes just to give them a bad taste(worked only so-so).

    • Hi Steven, I don’t actually know the ratio. I pour “some” in the bottom of the can pictured here – maybe an inch at most – and then fill it with water. I think I read the label once and noticed that I mix it many times stronger than is suggested, but I make up for this by watching how much I apply. The more concentrated the mix, the less I apply. I generally don’t want to pour too much to avoid the majority of it washing past the roots and out the pot. Instead I try to fertilize more frequently with less nitrogen.

      I like the suggestions for vinegar and chili pepper. Too much vinegar can harm trees, but in small amounts it can acidify the water which is good when the source is basic – the case around where I live. I think the vermin are actually going for the grubs that develop in the decomposing cottonseed meal – a process hastened by the fish emulsion. Less fish and fewer grubs, when I learn to safely kill them, ought to keep my trees in the clear – or so I hope.

  3. I use organic fertilizer cakes and live out in the country. We have raccoons, oppossums, and you name it. On top of that I have two English labs who operate on the theory of “I’ll eat it and if it turns out not to be food I can always throw it up on the carpet later….”

    After making my cakes, while they are still wet, I liberally sprinkle the top with the hottest chile powder I can find. In fact it is the 3rd hottest pepper in the world. The chile powder does not affect the trees in any way and seems to deter the various animals from eating the cakes.

    • Hi Ken, I’m intrigued by the chili solution – I may give it a try.

      And Ron – I’m surprised and sorry to hear about the rhododendron. I know they can be sensitive but wouldn’t have expected an established tree could succumb so quickly. Thanks for the note.

  4. I know what you mean about the smell! I used fish-based fertiliser for the first a couple of weeks ago and my yard smelt like the fish markets on a mid-summer day – my whole family complained.

    My dogs loved it though and lapped up the overflow with no ill-effects except bad breath.

    One negative though: I have a 2 1/2 metre height rhododendron in my garden which I’ve had for 20 years and it’s suddenly died (or is certainly seriously on its way to the garden in the sky) after the first treatment with the fish-based organic fertiliser.

  5. Wow, 1 inch is a lot more than the 2 tablespoons called for. But with an open mix it’s no problem. The grass under my benches up here in the rain forest grows very quickly.
    Glad to see I’m not the only one not on a precise fert schedule.

  6. I have been using fish emulsion as a folier feed for about four yearsnow at the rate of 1 oz. p/gal and use it on all my plante even maples I just do not use it in the heat of the day, early morning works best for me.

    • Maybe I’m over-feeding! I’ll try to pay closer attention to how much I use and see if more or less makes much of a difference.

  8. Jonas, from what I have seen (here and in person) your trees look great. I am not sure that you can really over fertilize them in your coarse soil mix (with diluted fish emulsion). Nice piece. John

  9. as an alternative to fish emulsion, I use seaweed extract on my bonsai – the smell is (to me) pleasant, like the ocean! No danger of over-feeding and the trees thrive on it.

  10. That’s interesting, seaweed extract is great for minors and other valuable nutrients but has almost no NP. Even less than fish emulsion. Right, no danger of over-feeding.