applying manure #211440 - Ask Extension


applying manure #211440

Asked September 08, 2014, 7:51 PM EDT

I'm planing to add manure to my vegetable garden and would like to know how thick (how much) I can apply it? The manure is from a dairy farm. When it comes out of the barn its sand, straw and manure but most of the sand and liquid is separated. I was hoping the straw/manure would not only add nutrients but organic matter and help loosen hard soil areas. My garden is about 10,000 SF. I'm going to add it this fall after everything is finished in the garden and till it in. Any input or suggestions are greatly appreciated. Thank You. 

Barry County Michigan

Expert Response

September 9, 2014

There are a number of items involved with your question.  I will attempt to provide answers.

First, adding manure is typically a good thing because it adds organic matter and helps to improve the tilth or working ability of your soil.

Second, I would ask if you have a soil test within the last 3 years.  The soil test will let us know if your soil needs phosphorus and potassium or if none is needed.  In addition to organic matter, the manure provides a source of nitrogen, phosphorus and potassium.

If you do not have a recent soil test, a soil test kit can be obtained from your county MSU Extension office or ordered directly over the internet from the MSU Extension bookstore.  The link is as follows:

Third, the most accurate way to determine the nutrient content of the manure is to have a manure analysis completed with a lab to determine the actual nitrogen, phosphorus and potassium content of the manure.

In the absence of a manure test, benchmark values may be used from the Midwest Plan Service to help determine how much in nutrients you would be applying.  The link below provides the benchmark values.  Dairy manure is on page 2.

In the table, dairy herd manure is provided showing 9 lbs. of actual nitrogen, 4 lbs. of actual phosphorus, and 7 lbs. of actual potassium in lbs./ton.

To convert your area into lbs./1,000 sq. ft., you need to know that there are 43,560 sq. ft. in an acre.

Based on having the soil test data and benchmark values, one can determine how much manure in tons/acre or broke down into lbs./1,000 sq. ft. that would need to be applied.

Fourth, from a food safety standpoint, the manure needs to be applied at a minimum of 120 days before harvest of the vegetable crop.  I tell commercial vegetable growers that if they have manure to apply to have it worked into the tract at least prior to December 31 to allow for the 120 days.  The 120 days comes from the MSU bulletin on Managing Manure in Vegetable and Potato Systems with the link provided below:

At the moment, 120 days is where things stand.  Having said this, under the new FSMA (Food Safety Modernization Act) the number of days that the manure would need to be applied prior to harvest most likely may change.  It is important to note, the more the manure can be composted prior to application the better.

Fifth, after making a manure application, I would recommend working it into the soil immediately to guard against nitrogen losses through volatilization or leaching.  Also, taking a soil sample after the manure has been worked in will pick up any additional nutrients supplied by the manure to give the most accurate test results.  I would recommend seeding the vegetable ground for the winter into the grain crop cereal rye.  The rye will gather any remaining nutrients left from the previous crop and that applied from the manure and hold it through the winter in organic form.  Then when you reach spring, the rye is terminated in advance of the next vegetable crop.

The answer to your question is more about how many lbs./ton of nutrients can I supply through the manure rather than how thick to apply it over the tract.

Feel free to contact me if I can be of further help to you at or (989) 670-8145 cell.


Hal Hudson, Ph.D.

Extension Horticulture Educator, Vegetable Production

Hal Hudson Replied September 09, 2014, 3:03 PM EDT
I had a soil test in the spring. #66Z8LL. I followed the recommendations using 12-12-12 and pellet lime in the spring. Last fall I moldboard plowed my garden and it drastically changed my soil levels from previous years especially my ph. It stated my organic matter was low. Should I still add the manure? If I test my soil every 3 years are the recommendations meant to be followed every year until the next test or just in the year the sample was taken? Thank You.
The Question Asker Replied September 09, 2014, 7:48 PM EDT


With your soil test code, I was able to go in and obtain a copy of your soil test results.  What I would like to do is fine tune things further going into the 2nd and 3rd year.  I need to study things over based on the information you have supplied.  I would write you up a plan moving forward for years 2 and 3.

Could you e-mail me your e-mail address/contact information so I can send my recommendations on to you and give you a call if needed?  Thanks.

Hal Hudson

Hal Hudson Replied September 10, 2014, 12:10 PM EDT

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