Analysis of Plant Spacing
There is no significant correlation between plant spacing and crop yield. The reasons for this are not completely clear. However, at least two possibilities come to mind. First, it could be that most growers have similar spacing between plants, thus not providing us with enough variation to produce a statistically significant pattern. Secondly, it is entirely possible that growers do differ in their preferred plant spacing. If so, then it is likely that widely spaced plants each get more light exposure, but there are fewer plants in the grow area; while closely packed plants each get less direct light, but there are more plants in the same sized grow area. Therefore, the tradeoff between number of plants and amount of light that each plant gets may be canceling out.
** Correlation is significant at the 0.01 level