Science vs anecdote

The work by Chalker-Scott has been mentioned here several times and I am yet to see any serious attempt to contradict it, it all seems pretty solid to me. More of her work is published in other places including IIRC some cases where the traditional remedy is shown to be actually effective. I agree with your comment about the need to test anecdotes more rigorously. Gardening myths are like rumours - people often accept them as being true because so many people accept them as being true.

One contributing reason for myth creation in gardening is that there are so many factors that together make a healthy plant it is very difficult to tease out whether the particular treatment you are using is the one actually responsible for the result you are getting.

Consider this real example which isn't about a gardening myth specifically but about how such things get started. At a meeting of a local growers society we were inspecting a nice mandala garden that included strawberries. The owner remarked that she was quite happy with the placement of the plot except that (despite being near the house) she had found red-belied black snakes near the strawberries a couple of times, with small children she was concerned. A spectator piped up "that is because they eat strawberries" and went on to explain how she had found such snakes in her strawberry patch. Now these snakes are not vegans, they live on small mammals and reptiles. I said that I could see two other possible reasons for snakes liking strawberry patches; one they are in the sun and two snakes are passing fond of mice who love strawberries. This is why you get snakes around chook houses, the snakes don't like chook food they like rodents who like chook food. The budding scientist who thought they ate strawberries did not want to let go of this idea. Thus old wives' tales get started.

David