evergreen tree fertilizer

Asked March 18, 2020, 6:31 PM EDT

hello. I am in Grand Junction. I have several pines (not sure species) and spuce (I think green) about 12 inch diameter. do evergreen trees need or benefit with fertilizer? If so what is best. thanks.
Bob Leachman

Mesa County Colorado

7 Responses

Hi Bob,
Yes, evergreen trees do benefit from fertilizer. You are a little early, I would apply the fertilizer when you start to see new growth just starting. A soil test would tell you specifically what you need as far as fertilizer. Without a soil test, nitrogen at a minimum is needed. Our soils are pretty rich in minerals, nitrogen is one that moves quickly thru the soil. Granular fertilizers that you broadcast over the root system of the tree, which happens to be 2-5 times the height of the tree, and then watered in is the best method. Something that is slower release over a few months is fine, ideally May-June and again in fall our good time to fertilize. This article has some good info and links on the topic. https://planttalk.colostate.edu/topics/trees-shrubs-vines/1708-fertilizing-trees-shrubs/

OK thanks...
Bob Leachman

How do I take a soil sample and where do I send it. If I use fertilizer how much to use per tree?
Thanks gain
Bob Leachman

https://extension.colostate.edu/topic-areas/agriculture/soil-testing-0-501/ Bob, you want to go down 6-8", remove top inch. Combine several samples around trees in a plastic bucket and mix. Need about a quart ziplock of soil, tell them your crop is spruce and pines. I prefer a fertilizer you can broadcast over the root zone which is at least 2 times the height of the tree. Not sure what labs are open, but here is the usu. I recommend. https://www.wardlab.com/

OK thanks. It looks like the lab is backed up with Corvid duties so will probably postpone that. I think I will try fertilizer so will google how much to apply. thanks
Bob Leachman

Good to know Bob, These are different times. We have some general fertilization information. https://planttalk.colostate.edu/topics/trees-shrubs-vines/1708-fertilizing-trees-shrubs/
Our soils are mineral rich. The main nutrient Nitrogen moves thru the soil quickly and is typically needed. Buying a product such as ammonium sulfate, often used for lawns, works for trees and is a good source of N. Read the label directions for spreading rates. Go with a low rate rather than a high rate. And don't get a quick release, slower is better.

OK thanks again...
Bob Leachman
Grand Junction