# A hypothesis about the most sustainable grass

I’ve written about zoysia growing faster than bermuda. Mike Richardson asked:

so, the real question…is that better? “Slow growing” has always been one of my favorite traits of zoysia…

I answered that it is better, and that I would explain my hypothesis later. Here it is:

*The most sustainable grass for a given location is the one that has the most growth per unit of N and per unit of H _{2}O applied.*

Definitions:

*most sustainable grass*is the one that requires the fewest inputs to produce the desired surface*location*is the temperature and light combination.

Assumptions:

- one considers all the grasses that could possibly produce the desired surface at that location
- from those, one selects those that don’t die when N and H
_{2}O are reduced

It follows that of the remaining grasses—by that I mean those that don’t die—the one with the fastest growth rate will require the fewest inputs to produce the desired surface, because one can supply low amounts of N and water to that grass. The one with the fastest growth rate also gives the most maintenance options, because one can adjust the growth rate across a wider range.