What is the best ratio of NPK of a slow-release fertilizer for a container-grown nursery?

Asked January 27, 2015, 8:41 PM EST

I live in Ontario, Canada, and will start a container-grown native tree nursery from seedlings in spring. The seedlings are either 25 to 40 cm or 25 to 60 cm and are mostly red maples, paper birches, white and bur oaks, red pines, black walnuts, and tamaracks. Depending on the seedling size, I will be using 1- or 2-gallon pots/containers. I would appreciate if you could please let me know the best ratio of NPK of a slow-release fertilizer for my application?

Outside United States

3 Responses

Hi, I sent your question to our Greenhouse specialist. Here is her response and contact info if you would like to contact her directly. I hope this information is helpful.

The following reference is from the Forest Nursery Notes - http://www.fs.fed.us/rm/pubs_other/rmrs_2009_landis_t001.pdf - and provides a good explanation and comparison of several controlled release fertilizer (CRF) brands and formulations used in native and conservation plant nurseries. CRF formulations provide the necessary macronutrients needed for growth - and some include minor elements as well. You would need to refer to the specific fertilizer websites to find the product that best fits your application needs (example: Apex has a fertilizer formulated for native plants with lower P levels). The polymers in CRF are designed to provide nutrient release over time and vary with product.

I realize this is a fairly vague answer, but hope that it can point you in the right direction of evaluating several commercial fertilizers on the market. The CRF technology has improved significantly over the last few years, so the products mentioned in this reference may be different today. Please let me know if you have additional questions – and I would be happy to locate the information for you!

Beth Scheckelhoff, PhD

Extension Educator - Greenhouse Systems
scheckelhoff.11@osu.edu go.osu.edu/firm

Dear Beth,

Thank you so very much for the excellent response and material you provided. I really appreciate your time and effort. This is a great site and I will definitely get back for more help and advice in future.

Warm regards,


I have shared your response with Beth.

We are glad we could be of service.

Best regards.