Today’s practice is to define the difference between “alternate” and “alternative.” Your Guru sees both of these terms used incorrectly quite often – she just edited a paper from a prestigious educational biological journal that used them incorrectly – setting the stage for misunderstanding in the scientific world!
Clearly, it’s time to straighten everyone out.
Alternate means a substitute for another (they chose an alternate candidate). It also means taking turns (the kids alternated between the swings and the slide – first one, then the other).
Alternative is a choice between two or more things (give me an alternative to voting for him).
So, unless you change your vegetable garden from organic to chemically-treated from one year to the next, you are not using an alternate method; it is an alternative method.