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Fertilizing blueberries #813385

Asked October 06, 2022, 12:00 PM EDT

Can I apply ammonium sulfate to my blueberries now-Oct 6th. Leaves have turned color but have not fallen yet. Thanks James neal

Greene County Ohio

Expert Response

Hello, 
Thank you for your question.  
In a nutshell, you should wait until spring, and here is why:

"Soil bacteria convert the
sulfur to sulfuric acid lowering the soil pH. It is important to note that this is a biological
process (slow) and not a chemical reaction (rapid). The bacteria are active, when the soil is
moist and warm. The soil temperature needs to be above 55F. The bacteria are not active in
the winter so fall applications of sulfur have little effect on the soil pH next spring."  quote is from Michigan State Extension, 
from the following link.  (Notice Elemental Sulfur is recommended, rather than aluminum sulfate.)
https://www.canr.msu.edu/uploads/files/Lowering_Soil_pH_with_Sulfur.pdf

(fall is the time to do a soil test to make sure nutrients are on track.)

Below is another great resource for backyard blueberry growers.

https://ohioline.osu.edu/factsheet/HYG-1422

I hope you find these helpful! And happy gardening!

Kathy M. Replied October 06, 2022, 3:39 PM EDT
Thank you so much for the information!

Had no idea that bacteria were involved in the process.

Once again, Thank You!

On Thu, Oct 6, 2022 at 3:39 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied October 06, 2022, 3:48 PM EDT
You are so welcome!  Thank you for helping me learn something new, as I also had no idea of the bacteria connection.  

Always new learning opportunities with gardening :-)
Kathy M. Replied October 07, 2022, 4:05 PM EDT

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