Bonsai cakes

Hey fellow bonsai friends, 

Here is my recipe for fertilizer cakes. I use these on my trees every year once the leaves have hardened off all the way through the fall. They breakdown throughout the year and I remove them before they go down for the winter.




Bonsai Fertilizers (bonsai cake)

Many people have asked what I do for my fertilizing regiment. Or, what should I be doing to promote healthy growth for my tree. This is a brief overview of what I do with my trees and why. Keep in mind this is a somewhat localized or climate specific breakdown of my hardiness zone (which is 6A). I also utilize an extended growing season with my greenhouse so please take this into account.

There are several items I use throughout the year and I will attempt to detail them out for you.

Basic fertilizers/supplements:

 Zamzows’ Thrive – This product is great for a kick-start in the early spring for hardy plants that are kept outdoors. This goes for all plants and vegetables.

SuperThrive – Tons of vitamins and minerals in this powerful compact solution that need to be diluted 1 drop per gallon of water. This fertilizer can be added to your weekly fertilizing routine. Do not replace your current routine with this product.

Fish Emulsion – This organic fish byproduct is great for adding to your weekly fertilizing routine throughout the growing season. The great thing about this product is that you cannot over-use this. It will not damage or burn your plants. Use caution, this product tends to be very foul smelling your wife or neighbors may not like you very much if you over use. Thankfully, there are variations of the product that have been de-odorized.

Miracle Grow 20/20/20 – This comes in several flavors from solid “BB” sized granules to powder that is intended to be water soluble applications. This fertilizer can “burn” your trees, so be sure to dilute properly and do not over-feed your trees.

Miracid – This acidifying solution is great for plants that thrive in acidic soil conditions (most evergreen trees and azaleas). I use this in two ways; one – I mix the granules into water as a diluted mixture and add this to my fertilizing regiment once a month. Two – I take the solution and apply this to the plant directly through a topical spray. This is (as I am told) a better application method because the foliage takes in more of the solution.

Bonsai Cake Fertilizer (slow release topical)

1qt Cotton Seed Meal

2 cups Blood Meal

2 cups Bone Meal

2 cups Kelp Meal

1.5oz SuperThrive

10oz Fish Emulsion

1qt 20/20/20 water soluble Miracle Grow (diluted into water-1Gal mixture)

2 cups Zamzows’ Thrive

3 tbl Ironite

4oz Elmers’ Glue (wood or original works fine)

Mix all these ingredients together; you should have a fairly soupy mix. If the consistency is not ideal for pouring/scooping flat into cookie sheets add a bit of water. Pour or scoop onto a cookie sheet and set in open area to dry. Once hardened into clay like consistency cut 1x1in squares. Allow to fully dry then remove from the cookie sheets. I wrap mine up in cellophane and store in a dry area. I apply several of these cakes around the edging of my bonsai pots (since the roots grow to the edge then down first this has been the best method for absorption by the trees) Note: if you do not store these cakes in air tight containers, you will see mold develop on them. Although this is unsightly, I haven’t had any damage to my trees caused by it. Thorough water will soon remove the mold that has accumulated on the surface of the cakes.


I have had great success with these cakes on my trees and in my garden. Keep in mind that if you have plants that are within reach of your dog and some cats, they will be attracted to these stinky beauties. I have had my dog eat several in a day. This might be why she is so weird, but she has been fine health wise since. I imagine that if an animal consumed enough they could become sick. So please be aware of this attraction.



Thank you for your support!

Jon White

Jon White