Planter 101: Form & Function

A planter isn't just décor – it's your plant’s home. The right pot supports healthy growth, better watering habits, and makes care simple. All too often we hear that one of the hardest parts of indoor plant shopping is how to choose the right planter.

At Promise Supply, we choose vessels based on both design and performance. We want your plant to look stunning, but also to thrive long-term. You’ll find this balance across our collections of Pots & Planters.

Lets demystify drainage, material, saucers, sizing, and everything in between.

Why Drainage Matters

Why do some pots have drainage holes, and some don’t?

Drainage hole(s) allow excess water to escape instead of collecting at the bottom of a planter. This prevents stagnant water (a major cause of root rot) and encourages airflow through the soil, which roots need to stay healthy.  

Most plants are sold in their plastic grower pots (aka “Nursery pots”), which are designed to drain properly for optimal health.

If you’re unsure how to water your plants, our How to Water Indoor Plants article breaks down the fundamentals step-by-step.

When directly potting we always recommend drainage. If you have strong plant instincts and bright light, planting in a pot without drainage can work. But overall, think of drainage holes as a safety net for plant health.

Why Do Some Planters Not Have Holes?

Not all planters are designed by people who grow (or know!) plants. In the design world, aesthetics usually come first: shape, finish, silhouette, colour. Functionality (including drainage holes) often comes second.

This is why so many beautiful decorative vessels are technically not ideal for direct planting. And that’s okay, as long as you understand how to use them.

No-Drainage Planters aka Decorative / Cache Pots

These are best used for drop-in planting:
You simply place the plastic nursery pot inside the vessel. Water drains safely through the nursery pot while the decorative container hides the mess.

It’s low-maintenance, renter-friendly, and protects your surfaces. Just ensure that plants don’t sit in excess water within the decorative pot. 

Direct Potting Into No-Drainage Planters

If you choose this route, you need to monitor watering more precisely. Potting with no drainage is always riskier, but still doable with experience and the right conditions.

Our best-practice tips are: 

• Water with only ⅓ of the soil volume
  
• Choose moisture-wicking materials (terracotta performs best)
  
• Ensure the plant receives adequate light
  
• Stick to species that prefer more consistent moisture

Planters With Drainage 

Planters with holes give you flexibility to either drop-in a nursery pot OR repot directly.

Do You Need a Saucer?

If you’re using the planter indoors, then yes! You want to ensure your surfaces are protected, and a saucer/tray will prevent water overflow, soil stains and any moisture wicking or leaking through porous materials.

Many pots with drainage include matching drip trays / saucers, particularly those intended for indoor use. Outdoor planters may not include trays, but you can easily modify them by:

• Adding a saucer inside the vessel (turning it into a cache pot) OR
• Pairing with an external saucer of your choosing 

Planter Size: What Size is My Plant & Understanding Nursery Pot Sizing

Plants are sized by the top diameter of their nursery pot (e.g., 6in, 8in, 10in). Nursery pots are fairly standardized, with up to 1in variation. Growers intentionally choose pots to match root systems, so you rarely need to size-up immediately.

When to Upsize the Plant Pot?

We recommend upsizing during spring or summer (active growth seasons), when you notice roots emerging from the base / growing out the drainage holes. You’ll want to go up about 1 nursery pot size (usually ~2in diameter). 

Oversizing too quickly or dramatically leads to moisture imbalance in the soil (and can lead to root rot), slow growth, and overall stress. Sizing up the pot does not equal more growth!

Sizing For Decorative Pots

Match the internal dimensions of the planter to the nursery pot’s top and base. Trim the nursery pot “lip”/handle if needed.

Sizing For Pots With Drainage Holes

Match the soil or current Nursery pot volume.

Planter Materials 

Different materials interact with water differently. Planters range from lightweight polyresin to heavy concrete, handmade terracotta, fibrestone, and ceramics. We recommend choosing the material based on placement, handling, budget and environmental exposure (some materials crack in freezing conditions).

Most natural materials (such as Terracotta and Concrete) will develop a patina over time as they age.

Terracotta & Unglazed Clay

• Highly porous
  
• Wick moisture (Great for over-waterers)
  
• Handmade styles are usually a higher price point, and Standard options are generally on the cheaper side

Ceramic (Glazed Clay)

• Non-porous
  
• Holds moisture longer
  
• Most indoor pots fall into this category, and pricing can range

Concrete & Cement

• Heavyweight
  
• Semi-porous over time (can stain surfaces without a saucer)
• Generally medium to higher price points, due to weight
  

Plastic, Resin, Poly-Composite

• Lightweight
  
• Fully watertight
  
• Generally more affordable
  

Stone Composites

These range in price, weight and durability: 

 

POLYSTONE: Polystone planters look like natural stone but are much lighter, durable, and weather-resistant. They don’t absorb water or crack easily and come in modern finishes that work beautifully indoors or outdoors.

FICONSTONE: Ficonstone combines fiberglass, cement, sand, and stone for a sturdy yet lightweight planter. Durable indoors or outdoors, it comes in smooth or textured finishes and modern or vintage styles - slightly heavier than Fiberstone but more affordable.

FIBERSTONE: Fiberstone combines crushed stone and fiberglass for a strong yet lightweight planter with a sleek modern finish. It’s durable, low-maintenance, and weather-resistant indoors or outdoors. Moulding wax can help protect it through harsh conditions. 

Are All Planters Safe for Outdoor Use?

No. Many materials (especially ceramics) can crack in freezing weather. Only use temperature-rated planters for outdoor year-round placement (we recommend bringing your nice terracotta indoors before those freezing temps hit!)

TL;DR If your planter doesn’t have holes, we don’t recommend planting into it directly – simply drop your plant inside with its current nursery pot. Choose a pot sized for your plant's current maturity and consider how the material will interact with moisture, age over time, etc.

If you're ever unsure, our team is always happy to guide you toward the right planter for your plant, space, and watering habits. You can always contact us for personalized recommendations.