Towards midsummer, it is common for tomatoes to fail to bloom or, if they do bloom, to drop their flowers.
Often the erring plants are very healthy and unusually large, which puzzles the gardener who does not understand that a youthful vegetative period must precede the reproductive phase in plants.
If the plants are overstimulated by too much moisture or fertilizer, the vegetative phase tends to be prolonged, delaying the reproductive phase.
Three or four pounds of commercial fertilizer to 100 square feet of garden space once a year is usually ample, even on relatively infertile soil, and soaking the soil to a depth of 6” inches once a week should supply sufficient water at any stage of a plant’s growth.
During Hot Weather
In very hot weather, however, plants that have not been overwatered or overfertilized sometimes drop their flowers.
This hot-weather blossom-drop is often associated with leaf-curl and blossom-end shriveling of fruit and is said to be the plant’s way of protecting itself against the dry atmosphere, which overstrains the capacity of the root system to supply moisture for transpiration.
The furled leaves reduce the area of transpiration exposed directly to the hot air; flower-dropping is a method of self-pruning; and the shrunken fruits release moisture to meet the drain of the atmosphere upon the foliage.
Since the root system is the limiting factor in the plant’s resistance to drought, little or no relief may be obtained from artificial watering.
44659 by Gordon Morrison