by Member of PSBA Boon Study Group

This article was submitted by John Callaway. It apparently was an e-mail response to questions raised at a Boon workshop. I have edited it for use in this newsletter. - ED.

In two recent workshops with Boon and Peter Warren, the subject of fertilizer cakes came up in. My home-made cakes seemed to be the desired product, and I was asked to share the recipe.

Before I get to that, I also want to recommend reading "Teaming with Microbes - A Gardener's Guide to the Soil Food Web" by Jeff Lowenfels & Wayne Lewis. I will pull information from there as well as from Boon's Intensives.

Organic fertilizer cakes are used to feed the microbes present in the soil mix. As you will rediscover in the book, it is the microbes that make the nutrients available to the plant. Soil structure plays an important role in the health and number of microbes. Also, all plants except for annuals thrive in fugally dominated soils. There must be sufficient drainage and oxygen for roots and microbes to be healthy. The Bonsai mix used here is Akadama, Pumice, and Lava in equal parts.

In shallow Bonsai pot culture, the fine organics have the potential of clogging the soil structure and drainage needed for health. That is why the cakes are placed on top of the soil to act like like natural leaf litter to the microbes. The cakes can also be removed to control the timing of nutrient availability - a tool that can be used to develop smaller leaves.

Boon's recipe is 5 parts cottonseed meal, 3 parts fish meal, 1 part bone meal, & 1 part blood meal; add fish emulsion & H2O; mix to consistency of ice cream, and scoop onto the tree. Use a sorbet scoop, or spoon it on.

The secret to this is that the fish meal needs to be pelletized to help the other ingredients stick together. It also cuts down on the odor.

From the book or your Nursery supplier you will find other organic substitutions. The Japanese Cakes are based on Rape Seed, but I haven't found it available here. Ingredients to help feed the fungus might be included, such as 1 part Kelp meal or soybean meal. The book suggests that the best is powdered baby oatmeal.

Then we get into actively aerated compost teas (AACT). These modern Brewed Compost Teas are available at some Nursery outlets. Used as a drench, it supplies a high concentration of microbes to the soil, which helps if it has been stressed by using chemical fertilizers (like putting salt on a slug) or fungicides, or by sitting on that hot bench all summer. Early spring after repotting, when you have a relatively sterile soil mix and you want to begin fertilizing, would be a good time to apply AACT.

So my recipe: (the parts = cups) Cotton Seed Meal - 5 C, Alaska Fish Pellets - 3 C (does have some other ingredients in it), Bone Meal - 1 C, Blood Meal - 1 C, Kelp meal - 1 C, DR Earth Compost Starter - 1 C (has alfalfa meal and beneficial soil microbes). Add Fish emulsion & H2O, 1 tablespoon non-sulfured Molasses, few tablespoons of screened sphagnum moss (the Adobe brick affect). This I let sit over night in a warm dark space then I added fresh brewed AACT to the right consistency to scoop onto the trees.

I then watered all the Bonsai with the AACT.

For those who don't have access to the compost tea, I have found the DR. Earth products contain some beneficial soil microbes. This is a observation from a local nursery, not from the book.

The amount to put on depends on size, season, health, etc; but, in general, you are not going to burn your trees with this. Begin fertilizing a few weeks after repotting - a few scoops at first, adding more as the weeks go on. In spring, I dry unused fertilizer rolled in logs of wax paper, then break off as needed. Keep adding fertilizer to the surface through the season, clustering older cakes together, so at some point they can be recognized as the oldest and removed. If cakes are removed for cultural reasons, clean the surface and add more soil mix if needed. By the end of summer, the surface should be mostly covered with little cakes of fertilizer. The microbes will feed on this and supply nutrients to the plant down to temperatures around 50F (although life doesn't stop at 40). So when winter comes, the cakes are removed and the surfaces cleaned. See Boon's November Article.

Please excuse the length of this when all that was asked was a recipe. Howeer, what was given barely touches on both Boon's Intensives and the information in the book. The new season starts with repotting!