What’s the White Stuff on My Soil? (3 Possibilities)
White stuff on soil is mold, salt buildup, or perlite. Texture and location tell you which.
The 3 Possibilities
Possibility 1: Mold
Texture: Fuzzy, spreads. Fix: Scrape off. Water less.
Possibility 2: Salt Buildup
Texture: Crusty, crystalline. Fix: Top water until water runs through.
Possibility 3: Perlite
Texture: Hard white pieces. Fix: None needed.
How to Tell Them Apart
| Sign | Mold | Salt | Perlite |
|---|---|---|---|
| Texture | Fuzzy | Crusty | Hard pieces |
| Spreads? | Yes | Slowly | No |
| Location | Surface | Surface/rim | Everywhere |
| Smell | Musty | None | None |
Common Questions
Is white mold harmful? Usually not.
Can salt buildup hurt plants? Yes. Burns roots. Flush monthly.
How do I prevent mold? Water less. Increase airflow.
Can I just leave perlite? Yes. It’s supposed to be there.
What water should I use? Filtered or rainwater if tap water is hard.
Will the white stuff spread to other plants? Mold can. Salt and perlite can’t.