Houzz Logo Print

Doing Soil Tests on Soil-Less Container Media

University of Massachusetts has a famous soil testing laboratory, and I have been using them for testing of in-ground soil. I noticed that they separately have an option to test container media. When does it make sense to test an organic soil mix like 5-1-1?

I have an ongoing problem with Azalea and Rhododendron doing well in containers of bark for about 18 to 24 months, after which they go downhill. Some would speculate that this is because the bark decomposes and ties up nitrogen. But why guess about that? Why not just test the soil and find the exact reason the plants are struggling? The concept makes sense to me. Am I wrong?

When doing a soil test on soil-less medium (e.g., a bark-based container soil) does it make sense to get an additional test done for nitrate testing? When using services like University of Massachusetts soil test lab, nitrogen testing is not included in the basic soil analysis. There is a separate test you can order for "side-dressing" of nitrogen, but clearly this test is oriented towards commercial farming, to help the farmer understand how much nitrogen to side dress at different times in the season. The reason this is confusing is that their list of services includes an option for nitrate testing in a regular soil test, but that option is missing for a soil-less media test:

I will call the lab as well, but they are very hard to reach by phone and I would like to get the tests ordered. So I would appreciate the perspectives of others.

Comments (14)

Native Plant Scapes
Average rating: 5 out of 5 stars5 Reviews
Your Friendly Native Plant Landscape Designers in Loudoun County