Preparations for a spring garden usually included the inspection of year-old, hanging gourds and the replacement of

those that were no longer “fit” for a new group of purple martins to use as nests.
The gourds had to be suspended from a rope or metal wire, placed about 18 inches apart and some 12-15 feet above the ground.
No plank or other leaning object could be placed from the ground to any gourd.
A cat or other creature could climb to the nest and kill the baby birds.
The lines of hanging gourds had to be placed out in the open, well away from woods or structures so the nesting martins could be aware of any danger that might be approaching the nest.
There was never a guarantee that the purple winged creatures would return every year.
Having a barn or pig sty that attracted flies and gnats, or a nearby pond that produced mosquitos, were the best conditions for attracting them.
Insects that preyed on garden plants were targets of the martins, as well. In plucking them from the plants, martins did no damage to the plants themselves.
The first martins usually arrived around the middle of March, after an advance “scout” had checked out the area for favorable conditions.
They made their nests in the hanging gourds, laid their eggs and hatched out new babies.
The first to arrive each spring began leaving with their new offspring around the end  of June. The later arrivals were usually all gone before the end of “dog days” in early August.
While the martins were never part of the spring planting of gardens, they made the tending and gathering of fruits and vegetables in them much more pleasant, particularly by limiting the presence of summer gnats and mosquitos.
In modern Dark Corner, plastic gourds and purple martin “hotels” have become popular, but, if one looks closely as new birds arrive each year, the old fashioned, real gourds are the first to be occupied.