Pot materials
Also known as Terracotta vs plastic, Clay pots, Glazed ceramic pots
In short
What a pot is made of changes how fast the mix dries. Unglazed terracotta is porous and dries fastest; plastic and glazed ceramic are non-porous and hold moisture longer. Match the pot to the plant and to how often you like to water.
How it looks
Unglazed terracotta is matt, orange-brown and absorbs water (it darkens when wet and may grow white mineral crusts on the outside). Plastic is light and flexible. Glazed ceramic has a shiny, sealed surface and is heavy. Orchid pots have extra holes or slits in the sides. Stone and concrete pots are very heavy and stable.
Signs
Mix in terracotta drying out noticeably faster than in plastic under the same conditions; plants in plastic or glazed pots staying wet longer, which matters in cool or dim spots.
What favours it
Drying speed also depends on light, temperature, humidity, pot size and mix. Humid tropical homes slow drying in any pot; air-conditioned rooms and bright windows speed it up.
Prevention
- Choose terracotta for plants that like to dry out between waterings, such as succulents and cacti, or if you tend to overwater.
- Choose plastic or glazed pots for moisture-loving plants or if you tend to underwater.
- Whatever the material, make sure there is a drainage hole; use decorative pots without holes only as outer covers.
- Soak new clay pots before planting so they do not pull water from fresh mix (Penn State suggests overnight).
- Clean and disinfect reused pots before repotting.
Treatment
Start with the first step and move down only if the problem persists.
- If a plant in terracotta dries out too fast, water more often, group plants, or move it to plastic or glazed ceramic.
- If a plant in plastic or glazed ceramic stays wet, water less often, use a coarser mix, or move it to terracotta.
Pros and cons
Pros
- Terracotta: excellent aeration and fast drying, which suits succulents and helps overwaterers; heavy enough to steady tall plants.
- Plastic: light, cheap, holds moisture longer so needs less frequent watering.
- Glazed ceramic: attractive and moisture-retentive.
- Orchid pots with side slits: fast, even drying for epiphytes.
- Stone and concrete: heavy and durable, resist tipping.
Cons
- Terracotta: dries quickly, is brittle and can build up mineral crust.
- Plastic: can stay wet too long in dim or cool spots; light pots tip over easily with tall plants; some decorative plastic pots lack drainage.
- Glazed ceramic: heavy, chips easily, often sold without drainage holes.
- Stone and concrete: very heavy to move.
Look-alikes
- Salt and fertiliser burn
- White crust on the outside of terracotta is mineral salt wicking through the wall; check leaf tips for salt damage.
Typical uses
All container plants.
Related
Sources
- Properly Watering Container Houseplants — Virginia Cooperative Extension
- Repotting Houseplants — Penn State Extension
- Potting and Repotting Indoor Plants — University of Maryland Extension
- Watering — Houseplants, University of Illinois Extension
Written in our own words from these sources. Check a product label before using any treatment.