Thank you for contacting Michigan State University Extension. I'm sorry to hear your trees are dying. You can purchase soil sample bags through Michigan State University Extension and receive recommendations directly from MSU. A&L Labs analyze the soil samples and send results to MSU Extension where a recommendation will be generated and sent to you by expert MSU Extension staff. All MSU recommendations utilize the latest research and follow state laws and guidelines. 

Home Lawn and Garden soil self-mailers including sample bags are available for purchase through local MSU Extension offices (https://www.canr.msu.edu/outreach/county) or even easier through the MSU Bookstore at https://shop.msu.edu/collections/garden-lawn/products/bulletin-e3154 where they are mailed directly to you. The self-mailers cost $26 and look similar to previous self-mailers if you happen to be familiar with those.

Please note, these soil tests do not test for heavy metals, pesticide residue on soil and plants, or PFOS. To find labs that test for these substance, please visit the following article: https://www.canr.msu.edu/news/testing-for-contaminants-in-soil-water-and-plants

Thank you for reaching out. Best wishes this growing season!