Best season for fertilizing / amending fruit tree soil?

Asked September 10, 2020, 5:11 PM EDT

I've seen some (seemingly) conflicting info about when to fertilize fruit trees via soil broadcast. In general, people recommend the fall (as it can take time for the fertilizer to make it's way through the soil). However, other people warn against applying Nitrogen / Nitrates during the fall as it will encourage late season growth (and thus get frost damaged).

What's the best recommendation here? If it's a nuance of "which amendment / which season," does this list make sense:

-N based (AMS, blood meal, fish meal, etc.): spring
-Lime: fall
-Gypsum: fall
-Rock Phosphate: fall
-K Sulfate, Mg Sulfate, Zn Sulfate, or Mn Sulfate: fall?
-Elemental sulfur (for blueberries): fall?
-Borax / Boron: fall?

These are all recommended by soil tests. But the tests rarely come with complete application rates, let alone timing recommendations.

Thank you!

Frederick County Maryland

1 Response

Hi- if you are applying a complete fertilizer (e.g., 10-6-4) we suggest applying it in spring around budbreak. )Blueberry is fertilized with AMS at bloom and again 2 weeks later.)

We agree that applying lime, gypsum, sulfur, borax, and the sulfates in the fall is preferable to spring. Be aware that if your soils are low in P, the rock phosphate is so slowly available that it will probably not provide enough plant-available P next spring/summer.