What are the soil moisture requirements of flowers?

Because of differences in the moisture environment of their places of origin, various flowers have different water requirements, and the environmental conditions suitable for their growth also differ, and they have developed different ways of adapting in terms of morphology and physiological structure. For example, cacti native to the desert regions of the Americas, in order to adapt to the dry environment with extremely scarce rainfall there and to reduce water evaporation, had their leaves strongly degenerate and become smaller over the long course of evolution, turning into needle-like spines, and are covered with very thick cuticle and wax layers, which helps keep the water in their bodies from evaporating, so that even if they are not given water for several years in a row, they can still survive tenaciously. Most evergreen flowers from warm and humid regions, however, because their leaves are large and thin, their tissues are tender, and they lack the protection of dense, thick wax and cuticle layers, and their stomata are often open, have a very large transpiration rate, which is very unfavorable for storing water in stem and leaf organs; in order to maintain the water balance in the plant body, they need a constant supply of sufficient water.

It varies at different growth and development stages. Generally speaking, after sowing, relatively high soil moisture is needed in order to moisten the seed coat so that it swells, which is favorable for the germination of the radicle and plumule; after the seeds germinate and emerge from the soil, the root system is relatively shallow and the seedlings are very slender and weak, so the surface soil should be kept moderately moist; afterward, in order to prevent the seedlings from growing excessively and to promote the plants' ripening, soil moisture should be reduced, which is the so-called "hardening of seedlings"; hardening seedlings at the seedling stage is one of the effective measures for cultivating strong seedlings; when they have grown to a certain point, relative drought (called "withholding water" or "controlling water" in flower cultivation) can also cause the branches to stop growing rapidly and accumulate nutrients to supply flower bud differentiation. Flower bud differentiation is the turning point from vegetative growth to reproductive growth; at this time, appropriately controlling water for Japanese apricot, peach, Euonymus alatus, kumquat, crape myrtle, redbud, and others, and watering less or stopping watering several times, can inhibit or delay the growth of stems and leaves, advance and promote the formation and development of flower buds, and thereby achieve the ornamental goal of lush blooms and abundant fruit. But during the flowering period of flowers, the supply of soil moisture should be kept at an appropriate level; too little water makes flowering poor and shortens the flowering period, while too much water can also cause flowers and buds to drop. In addition, air humidity also affects flowering; too low humidity shortens the flowering period and prevents the various inherent flower colors from showing, but too high humidity can also cause petals to rot and promote the spread of pests and diseases.