Most years i make fertiliser cakes from a range of ingredients (usually what is cheap or on special when it comes time to buy them) although the cakes that I have previously made have never really lived up to expectations.

For those that have used the fertiliser cakes in Japan I am sure you would have noticed an interesting thing. When the cakes have been on the soil surface for a few days they begin to get a white felt like mould on the underside and begin to omit a pleasant fermenting kind of smell.  When I worked with Mario Komsta, he always got excited when he saw this mould as it was a sign the cake was breaking down and feeding the bonsai.

The cakes I have been using here in Australia have never got the mould that those in Japan got. I put this down to a couple of things. Firstly climate. Japan gets a whole lot of rain over their summer where as here in Australia we are usually hot and dry for most of the summer. The problem I was having with my cakes was that they were drying out and were then hard to re-wet and get them breaking down again. Japan was always so humid over summer that the cakes once wet stayed moist and were able to break down.

To try to combat that this year I am trying using my ingredients loose inside tea bags. The idea is that they will be much easier to re-wet each watering and hopefully break down much more quickly and hence feed my trees better.

Tea bags, for making your own tea blend bags and a pair of scissors I need to re-profile.

I found a cheap supplier of tea bags in the form of a Japanese 100yen shop called ‘Daiso’ which has just opened a couple of stores in Melbourne. $2.80 for 100 bags.

The mix I am using this year is fairly basic:

  • Cottonseed meal – 5 part
  • Blood and bone meal (including trace elements) – 5 part
  • garden lime – 1 parts.

Filled bags.

The process of making the fertiliser bags is fairly easy and mess free. I fill the bags with a large spoon full of my mix and fold the bag shut. The cakes are now pretty much ready to go on the trees,  but I do one more step prior to putting them on my bonsai.

Soaking in fish emulsion.

I soak the filled bags in a fish emulsion solution to fully wet the ingredients and add a bit of extra fish emulsion kick to them.

Bags on the bonsai.

Once on the soil I like to place a small dimple in the top of the bag/mix so that every time I water, a small amount of water pools on the surface of the fertiliser and helps to re-wet it.

Now it’s not the most attractive solution but it does have a few extra benefits out side of easy re-wetting. Firstly because all the ingredients are contained in the tea bag this stops a lot of the loose material clogging up the soil surface and hindering drainage. Then they are also very easy to remove and replace at de-candling time which is also a plus in my book. Possibly the biggest side benifit is there is no smell while making the cakes using this method, and no smell means no complaining neighbors and stinky backyard. Also not having to dry cakes means you can make them early in the season before the weather heats up to drying temps.

I look forward to seeing if i get the white mould and the working fertiliser smell……. fingers crossed!