A pot becomes noticeably lighter as water leaves the growing mix. That simple change integrates several conditions at once: plant use, evaporation, temperature, light, container size, and soil structure.
Build a reference
After watering thoroughly and allowing the pot to drain, lift it safely and notice the weight. Check again over the following days. For a small plant, one hand may be enough; for a heavy container, gently tilt one edge rather than lifting the entire pot.
Combine weight with a soil check
Weight tells you how much water remains overall, while a finger or wooden skewer reveals moisture near the surface and within the mix. Plants that prefer partial drying can be watered when the pot is clearly lighter and the appropriate upper layer is dry.
Know the exceptions
Self-watering containers, very large pots, decorative cachepots, and dense mineral substrates need different checks. Never lift a fragile or unstable pot. The method is a learned comparison, not a universal target weight.