Choosing a pot: size and drainage
Why holes matter, which size to pick and how materials differ
Drainage holes come first
Every pot needs drainage holes, so roots never stand in water. Roots need air as much as water, and extra water that can't escape slowly suffocates and rots them, even when the top of the soil looks dry.
Love a pot that has no hole? You can often drill one.
Skip the gravel layer
A layer of gravel or broken pots at the bottom doesn't help drainage. Water won't move from fine potting mix into coarse gravel until the mix above is soaked, so the wet zone just sits higher, right where the roots grow.
Fill the whole pot with potting mix instead. Drainage material in a pot only gets in the water's way.
Pots inside pots
To use a decorative pot without holes, treat it as a sleeve, often called a cachepot. Keep the plant in a plastic nursery pot with holes and set it inside.
Lift the inner pot out to water at the sink. Otherwise, empty any water that collects in the outer pot, or it will soak back up into the soil.
Pick the right size
When you repot, move up to a pot only 1–2 inches (2.5–5 cm) wider than the old one. In a pot that's too big, the extra mix the roots can't reach stays wet, and instead of growing into it, the roots rot.
For tall plants, pick a broad, heavy pot with a wide base so they don't tip over.
Materials compared
Each material changes how fast the mix dries.
- Unglazed clay (terra cotta): porous, so it dries out faster. Good for cacti, succulents and anyone who tends to overwater.
- Plastic: the lightest pots. They hold moisture well, so water less often.
- Glazed ceramic: holds moisture longer than clay, and its weight steadies tall plants.
- Dark pots and metal pots heat up in full sun and can burn roots, so keep them out of strong sun.
Saucers
Use a saucer indoors to protect floors, but empty it after watering. Water left standing in it can rot roots, carry salts back into the pot and breed mosquitoes outdoors. Unglazed clay saucers can also wick water onto furniture.
Related plant problems
Sources
- NC State Extension: Extension Gardener Handbook, 18: Plants Grown in Containers
- Washington State University: The Myth of Drainage Material in Container Plantings
- Iowa State University Extension: How to Select Quality Plant Containers
- RHS: Overpotting
General guidance, not a diagnosis. Written by PlantWiz in our own words from the sources above.