Controlled release fertilizer (CRF) recomendations?

[James W.]

I have been using Osmocote and/or Nutricote or similar "slow release" fertilizers on my trees every couple of months with good success but I have never been entirely happy, I felt like the release timing was uneven and shorter than advertised. I was recently made aware that the commercial potted tree producers do NOT use these brands. Many of the pros use products that are designed to provide a better balance of more nutrients for 1-2 years.
Does anyone know a brand name and/or supplier for these professional grade CRFs?

 

[bwaynef]

I've seen Florikan recommended. I'm not positive I can recommend it, but I'm experimenting with it (again) this year. Hopefully I'll have some info to pass along.

 

[Glaucus]

Osmocote is a professional product. And with every generation they improved the release curve. It is the industry standard. I don't know if they are as good as advertised. Or if they have a smaller competitor that has a better product. But it is what a ton of pro nurseries use. It may be true though that people that produce lower value plants, like landscape trees, use a cheaper product.

If you want to see their 100+ page brochure on fertilizers for container growing, then it is here:

International Brochure 2024 - Ornamental Horticulture

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[RaginCajun]

Underhill bonsai buys a popular commercial grade CRF in bulk and then bags it up into hobby sized bags for sale. They have a website. I use it on my trees in development. I can’t remember the name of the brand but in one of their recent YouTube channel videos or shorts Evan discusses it and says what it is.

 

[Shibui]

I was recently made aware that the commercial potted tree producers do NOT use these brands.

You should go back to your source and ask this question.
Personally, I'm not sure your source is giving you completely accurate info, or maybe you misunderstood. Many of the commercial growers I know use either of the brands mentioned.
Scotts (Osmocote) make a much larger range of CRF than is generally available to retail buyers. https://icl-growingsolutions.com/en-au/ornamental-horticulture/brands/ I was using Osmocote Exact Lo start 16-18 month https://icl-growingsolutions.com/en-au/ornamental-horticulture/brands/osmocote-exact-standard/ for many years but my supplier won't deal with Osmocote now so I moved to another brand. The Osmocote Exact range has tailored release rates. The Lo start releases slowly for the first few months then gradually increases nutrient release. That seems to match the needs of trees for bonsai - less in the first weeks after transplant then more through growth spurts of Spring and Summer. 16-10 month should still be releasing nutrient through the following Spring and most of Summer. It's still Osmocote, just a different formulation. Also only available in 25kg (I think?) bags.
Nutricote also has a larger range of CRF. https://www.growise.com.au/nutricote-controlled-release-fertiliser Their 'Fawn' product is 700 day release so that's close to 2 years. Also only in 25kg bags.

If you want to find these products you'll probably need to look for suppliers that cater for commercial growers in your area.

 

[Glaucus]

Maybe the source means that in the US, Scott's sells gen2 osmocote to the consumer. When they have gen 3, 4 and 5 products as well.
Not entirely sure if this is what they do, but I vaguely remember that when I was confused about what 'osmocote plus' actually was when comparing it to their website with their product line.
The consumer market must be tiny compared to the professional market.