The Main Problem
Many a indoor plant is lost to overzealous attention; hydrating them every time you pass by proves lethal. Using ice cubes to hydrate promises more gradual and more deliberate hydration. But, does it really work?
The Popular Hack
Place one or two ice blocks atop the soil. The concept posits while the ice thaws, it slowly provides water, giving the roots a chance to take up it and preventing waterlogged earth.
Examining the Practice
This technique works best for little planters and species that dislike overwatering, such as Phalaenopsis. However, most of tropical-loving indoor plants dislike cold temperatures. Their root structures evolved for heat, and icy water can stress or harm them. The surrounding conditions is a big factor in the technique's efficacy: in a warm space, the ice will thaw very quickly, giving minimal value, while in a chilly room it may stay too long, chilling the roots and reducing water uptake. Always ensure ice cubes are frozen from pure, filtered water and never place them directly against the base or exposed roots.
Putting it to Experiment
I tested on a Phalaenopsis. A couple of cubes per week kept the roots evenly hydrated and avoided waterlogging. In contrast, trying the identical trick on a prayer plant caused discoloration at the tips of the leaves, a definite symptom of chill damage.
The Final Verdict
The ice cube method may work for Phalaenopsis, yet it isn't ideal for many tropical-origin houseplants and hinges significantly on room climate. Thus, this trick won't be advised; tepid water given carefully continues to be the most reliable technique to effectively hydrate your green companions.
