Salt Flush

Every watering leaves behind a small amount of dissolved mineral salt as water evaporates or is taken up by the plant, while the salt itself stays in the soil. Over repeated light waterings, that residue accumulates in the root zone and can eventually reach concentrations that stress or damage the plant, especially in containers, where there's no surrounding soil to dilute it.

A flush uses roughly double the normal watering volume in one application, applied slowly enough to soak in rather than run straight through, so the excess water carries dissolved salts down below the root zone and, in a pot, out through the drainage holes.

This matters more in the UAE than in regions with regular rainfall, since natural rain is usually what flushes salts out of soil over a season; without it, the job falls entirely to irrigation. A monthly flush is a common recommendation for potted plants watered with tap water, and a visible white crust on the soil surface is usually a sign a flush is overdue.