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Testing Soil and Water

Fertility and Nutrients (Results)

I scanned the soil test results from MSUE - many thanks to Gonzalo and Lucy for collecting the sample and submitting it for analysis back in April. I uploaded the scan as a two-page PDF document in this site. It's attached to this page and you can download it below. It requires Acrobat Reader to view. 

The soil test report date is April 23, 2009. The collection date was several weeks earlier.    I'm pretty sure we added the manure and city compost after the samples were taken, so factor that into your thinking.

There are two pages: the results and the interpretation/recommendations. 

MSUE gives their recommendations in terms of pounds of NPK per 1000 square feet. I'm working on converting those recommendations to pounds per garden plot. Our plots are 20x20, yielding 400 square feet, which means if you multiply the MSUE numbers by .4 you'll get what you need for a single plot. For two plots, double it!   All that is easy.

I'm trying to cast the recommendations in terms of pounds of blood meal, cottonseed meal, bone meal, etc. I'll be making some assumptions about the percent-by-weight appropriate for each material. Then you'll just need to incorporate the right amount of blood, cottonseed, bone, etc., and not have to worry about any of the math. Hopefully this will be helpful to people if they are considering amendments to their plots. 

The test and analysis really just deals with the big three, soil ph, and nutrient holding capacity.  So the other micro-nutrients  you might be interested in are still unknown.

Of course adding organic matter (manure or compost) is your easiest choice, and you can never go wrong there.  But if you are interested in taking action for the MSUE analysis, you can still do that.

Finally, I think we agreed to do a contaminants test, at least for metals and lead.  But we also need to get a site history to make sure we are testing for the right things.



Lead (Results)

The fee for a basic soil test for lead via MSU Extension will be $23.00, as a check payable to Michigan State University.   I'll take care of it and Nancy knows that I'll need a reimbursement.

I collected 20 samples from our garden by zig-zagging around the area with a clean trowel and plastic bag.   On the advice of Extension staff, I dug down about 6 to 8 inches for each sample.

The collection date was Tuesday, May 26, 2009.

The samples were thoroughly mixed and air-dried, and two cups will be submitted to the Extension office on Zeeb Road on Friday, May 29, 2009.

Results will take two weeks.   This will only be a test for lead.   When I get the results I'll scan them and upload to the site for other to check out, just as  I did for the fertility/nutrient results.

Nancy is contacting the city manager about a site history.  After that step, we'll know more about what kinds of things to test for if we decide to investigate further.   So stay tuned on that front.

I know the contaminant test is coming a bit late, since all of us are invested in terms of time and labor, but I still think it's a good idea.   Hopefully we'll get good news and rest a little easier with our new garden and plots.  But if there is a problem, better to know about it sooner rather than later.


Update:  It's Wednesday, June 17, 2009, and the results are in: 9 parts per million for lead in the soil sample from the Community Garden.

From what I can tell, that's pretty darn good news.  The results included an interpretive letter from Wisconsin Extension service that said levels of 500 to 1000 ppm would require special care when the land is used for garden/agricultural purposes.   But we only have 9.

This site (the Minnesota Extension service)

  Lead in the Home Garden and Urban Soil Environment

has a bit more info and says, in part:

"Background concentrations of lead that occur naturally in surface agricultural soils in the United States average 10 parts per million (ppm) with a range of 7 to 20 ppm."

So we are right in line with normal levels of lead.

Just so you know,


Gonzalo Silverio,
Dec 29, 2010, 8:47 AM