Soil tests

We provide soil testing services for clients around the world through Brookside Labs, and have an active research program in the area of turfgrass nutrition, soil and plant analysis, and sampling methods.


My books about greenkeeping, turfgrass science, clipping volume, and MLSN.


Minimum levels for sustainable nutrition—MLSN—is a modern method for interpreting soil tests for turfgrass.

One thing I'd like everyone to understand about MLSN

Joe Hollier wrote to me a few weeks ago asking if I could write something about MLSN for the STANZ newsletter. I sent this quick reply: Gosh, this is the kind of thing I should say no to because I’m quite busy and don’t want to add more things to do to my list.

The Secret MLSN Operations Manual

This is a compilation of the best content from the MLSN newsletter. It’s all about this modern method for soil test interpretation for turfgrass—how it works, how MLSN was developed, answers to common questions, and some fun stories about this project.

Adding potassium fertilizer does not increase the soil's ability to store it

You’ve probably listened to one of my seminars in which I explained why conventional nutrient guidelines for turfgrass are broken. Jackie Guevara’s thesis on “Effects of Different Soil Testing Philosophies on Creeping Bentgrass and Annual Bluegrass Putting Greens” is an excellent demonstration of this.

Simple solutions to a difficult problem

When Bernd Leinauer introduced me prior to this talk, he mentioned that I’m one of the most controversial turfgrass scientists today. And the reason for being controversial happens to be the very topic of this presentation1 that I’ve uploaded today to my YouTube channel.

MLSN and turfgrass nutrient recommendations

GCM Magazine has another article about the SLAN and MLSN methods for soil test interpretation. The article summarizes Jackie Guevara’s research (with Kevin Frank at Michigan State University) into turfgrass response when P and K applications are made based on MLSN.

Lack of response to a fertilizer application

These pots of variegated tropical carpetgrass (Axonopus compressus) received an application of granular 16-16-16 fertilizer twelve days before this photo was taken. The grass on the right responded with a lot more growth than did the grass at left.

Extending the beer analogy

I’ve explained how MLSN works by telling a story about beer. Specifically, about a natural and logical method to figure out how many beers to buy at the store prior to an upcoming party.