Fertilize with Bio-Gold &/or Osmocote

I’ve just started using Bio-Gold fertilizer pellets (as well as Dr. Earth fertilizer) after hearing what Ryan suggests. I’ve been using Osmocote and Miracle Gro. Am I correct in thinking that the Bio-Gold will REPLACE the Osmocote as opposed to SUPPLEMENTING it? My assumptions aren’t always correct!
Both products have their pluses and minuses for me:
+ Osmocote needs to be applied less frequently.
+ Osmocote is far less expensive.
- Osmocote leaves insoluble, unsightly shells that should be removed from the soil. (How many people do this?)

+ Bio-Gold is a more complete formula.
+ Bio-Gold leaves no residue.
- Bio-Gold must be applied three times as often.
- Bio-Gold costs far more.

I’m a believer in using the best products and tools one can afford since the working experience and results are worth the price.
It will be interesting to see the results.
Thanks for your input.

Yes most likely you want to cease the use of osmocote if you are using biogold.

Osmocote (being a chemical fertilizer) will likely kill the bacterial and fungal microbiome that biogold & dr earth life are trying to promote.

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FWIW the cost of biogold is quite high and as such, this year I’m trying out other locally available organic fertilizers.

I’d be interested in your opinion of your alternatives. Are they cakes/cubes like B-G?

Right now I’m using stuff that isn’t in a cake form. They are mostly powders and I’m putting it in tea bags. It’s okay, not great, but I didn’t have the time to make my own cakes this year.

I posted a bit about my method of making cakes using mostly Dr. Earth and Alaska Fish Emulsion in the Fish Emulsion thread. it takes me about 50 minutes start to finish including clean up to make 220 6g cakes using a 1/2 T cookie Scoop. I think I can drop that to about 40 minutes using the 1 T scoop. For reference, BioGold pellets are a bit more solid than my cakes and are 1.45 g average. My teabag fill rate with Dr. Earth was typically about 6/min vs. the 5.5/min that I expect with the 1 T scoop. Finally, the cakes look better than the teabags in my opinion.


Marty, what is the NPK ratios of your cakes?


Keith - No fair asking hard questions on Sunday morning!

I have done my measurements by volume and N-P-K is by weight so I had to guestimate the bulk density for most of the ingredients (I measured the Dr. Earth Lawn fertilizer at 0.69 g/cc since it is the major component). I plugged it all into a spreadsheet and if my density guesstimates are at all close to accurate it is 7.4-0.5-3.4. The Dr. Earth is 9-0-5 which is the driver for it being out of balance.

Now I need to reformulate and measure by weight. Increasing the P is easy by dramatically increasing the amount of Bone Meal. I will need to find a source of K - Potassium that becomes available in the typical 4-6 week lifespan of a cake on the soil (Green sand is out).


I measured the bulk densities of my ingredients and my guesstimates where not far off. I then hunted down locally available sources of potassium (K) and found both Langbeinite (K2Mg2(SO4)3) which is 0-0-22 and a dehydrated Kelp which is 0.5-0-10. This lead to a complete reformulation to get a more balanced N-P-K mix which I will see about mixing up in the next couple of days.

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Marty, sorry to put you through all the hassle, but at least you also now know. I simply use liquid miracle grow, with a dose of seaweed extract added 3 times per year. The formulation isn’t great but it seems to work.
Trying to get 10 10 10 is so difficult or expensive I admire anybody who tries to create their own. Maybe you should start selling it?

I, too, had been using MiracleGro plus Osmocote along with fish emulsion and periodic Ironite since I started my Bonsai adventure about a year and a half ago. This was on the recommendation of a skilled local Bonsai nursery owner/teacher. The results have been good, with 15 or so healthy trees. After watching Mirai and seeing how Ryan tests products I decided to follow his recommendations. Some need to be filtered through the climate differences between the Pacific Northwest and semi-tropical Florida, though with well over four inches of rain the last two days I wasn’t sure where I was!

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I agree with your analysis, cutting the use of all chemical based fertilizers should only benefit the long term health of your trees. I have been using Bio-Gold on my trees for 10 years now and highly recommend it. I cut the use of chemical fertilizers such as Miraclegrow and Superthrive on bonsai planted fully into bonsai soil, although i do see benefit from those on newer collected material, the long term results show on the exterior of the pots with a white almost salt like residue. Which i believe would have to be building within the pot on the soil and root mass as well. While fertilizers like osmocote have to be changed less i do not know how consistent the potency of the fertilizer remains after a few months of heavy watering. Personally i like organics you can watch visibly break down and know when to replace. @MartyWeiser , very interested to see the results from your home made fertilizer tests as Bio-Gold is quite expensive to import, but buying in bulk saves in the long term, i buy enough to last a couple years… yes its expensive and stinky to store this much but this way it is always there to replace when the cakes break down and know that the chemical balance remains consistent. I figure these trees should outlive me so i will spend some extra on proven fertilizer . Trees have been happy and pushing new buds every year so i am a believer in Bio-Gold

I made batch of my revised, more balanced formula today and it took the same 50 minutes as before, but this batch had to mix a bit longer since it is a bit harder to dissolve/break up some of the components. The mix sheet is below and I list zero cost for the materials I have in huge volume. This compares with the $16.20/kg I paid for 10 kg on BioGold on special. This is a full batch for my 5 quart KichenAid mixer. I used the 1 T Norpro scoop from the kitchen (need to buy my wife a replacement) and got 106 cakes. PM me if you want a copy of the spreadsheet via e-mail for your own experiments.

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I have been confused about fertilizers and have listened to numerous “experts” I have used Bio Gold, but found it has it’s draw backs in that it can burn moss and it gets messy at times and never quite know when to replace it since it never seems to dissolve over time (Months). I recently read about and purchases Seafuel Bloom, which some enthusiasts have recommended. Any thoughts on Liquid organic fertilizers?

I used a mix of Alaska Fish Fertilizer (organic) and some Miracle Grow (inorganic) in a unit designed to mix the contents into the spray at the end of the hose end. With a slight modification I put it between the end of the hose and my watering wand. It worked fairly well and the trees did better than straight inorganic. Biggest issues were: 1) it was an awkward set up, 2) the fertilizer ratio dropped as I watered, and 3) the residual between weekly uses tended to ferment so that the addition of new organic fertilizer resulted in a stinky volcano coming out of the mixing jar!

Bloom Seafuel is a mix of fish emulsion/seaweed and humates. It is great for improving action within the soil and creating a rich growing environment but is not an actual fertiliser… In addition to that I use BioGold as a feed but I now soak it in water for a week or so and then apply. A few pellets in a 2ltr bottle work well for me after guidance from Peter Warren… I formerly applied it in solid form but speculation is that the liquid method works better in a UK climate. I am also trialing a UK supplied 5-5-5 organic fertiliser. So far results in the way it breaks down are promising. I use no chemical feeds at all, totally organic.

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Relatively same approach here, though i mix my BioGold in 5L canisters at 3x strength to last me longer for the same preparation time. I picked up some Tibular NF fertilizer at last years trophy. They have a low N formula for supporting soon after a repot. So far it looks to breaking don better than Biogold.

The biggest benefit of using organic fertilizer is micro activity. I have been following Jonas on bonsaitonight for a while and he has used rapeseed meal for a long time with good results. I bought 50 lb of that with $75 shipped I think and it will last me a couple of years. Putting it in teabags and lay on the surface has been working well for me. I still occasionally use Micro-Gro though to supplement. Maybe one a month or so just during the growing season. I am sure Bio-Gold is better than rapeseed meal but it is just too expensive for trees in development.

Fertilization is a beast. I’ve come to the conclusion that no one really knows what’s right or wrong (to an extent). Instead, they know what’s worked for them plus a dash of their inherit bias.

While the microbial culture is super important for conifers I’m starting to wonder if it’s as crucial for deciduous trees. I recently visited a practitioner that’s been at it for 30+ years. All of his trees are doing well. Better than well, I should say. Especially trees that he has in development. When I asked him what he fertilizes with I was very shocked to find out that he pretty much only uses chemical ferts. Then the latest Andrew Robinson podcast further bolstered the idea with me.

I’m still going to lean organic in my applications. Bio-gold, fish emulsion, and kelp. However, I am going to be a bit more open-minded about chemical ferts. Especially in my ground growing efforts. To that end I’ll be giving Dyna-Gro a shot next summer.

To crib off Michael Pollan: “fertilize; not too much; mostly organic.”