What are they made from

Modern plant containers are made from a huge variety of materials and come with an even greater range of finishes.

The most common materials are glass reinforced plastic (known as GRP or fibreglass), aluminium, steel, glazed earthenware and stoneware, unglazed terracotta, moulded plastic, wood and concrete.

Each material has some distinct properties as well as a range of advantages and disadvantages.

Glass reinforced plastic (GRP)

Properties: lightweight, waterproof, durable and available in a huge range of shapes, sizes and finishes, including some that are almost indistinguishable from other materials.

All of the following containers are made from GRP.

Advantages: lightweight, available in a wide variety of shapes, sizes and finishes, inexpensive, waterproof, resistant to cracking, resistant to dents, scratches and crazing, ideal for all growing systems, reusable and can be refurbished.

Disadvantages: Not recyclable, special shapes and colours have to be made to order, plain-coloured finishes can look a bit 'cheap'.

Aluminium

Properties: lightweight, waterproof and durable.  Aluminium containers are usually round as they are often made by a spinning process, however containers can be made in square and rectangular shapes by pressing and folding the sheet metal.  Polished and brushed finishes are both readily available.  It is also possible to have a coloured lacquer applied.

Advantages: lightweight, waterproof, available in a wide variety of sizes and finishes, resistant to cracking and crazing, reusable and recyclable, ideal for all growing systems.

Disadvantages: relatively expensive, limited range of shapes, can get dented and scratched.

Stainless steel

Properties: durable but heavy containers.  Available in a similar range of finishes as aluminium.  Round containers are common, but there is a wide variety of square and rectangular containers made by folding sheet metal.

Advantages: strong, waterproof, resistant to scratches and dents, suitable for all types of growing system, available in a wide variety of sizes, recyclable and reusable.

Disadvantages: relatively expensive, heavy, shows fingerprints and other greasy deposits, limited range of shapes available.

Glazed earthenware and stoneware

Properties: heavy and sometimes quite fragile containers.  Glazed earthenware and stoneware containers come in a wide range of shapes, sizes and finishes and can be very stylish.

Advantages: available in a wide range of sizes, colours and shapes, deep lustrous glaze, top-quality products look stunning, some ranges are very inexpensive.

Disadvantages: very heavy and require careful manual handling when being positioned, often need to be waterproofed if they are not glazed on the inside, prone to cracking and breaking, can look a bit rough-and-ready.

Unglazed terracotta

Properties: heavy and fragile containers.  Good quality examples look very classy but cheaper ones just look like overgrown flower pots.

Advantages: mass produced examples are relatively inexpensive, classic plant container for conservatories.

Disadvantages: very heavy and require careful manual handling when being moved, fragile and prone to cracking or breaking, must be thoroughly waterproofed to prevent surface staining and condensation.

Moulded plastic

Properties: lightweight containers available in a wide variety of sizes and colours, though shapes are limited.  Often sold at the budget end of the market.

Advantages: lightweight, waterproof, inexpensive, available in a wide range of colours, suitable for use with all types of growing system.

Disadvantages: limited range of shapes, styles and surface finishes.

Wood

Properties: lightweight containers made from a renewable source.  Shapes limited to simple circles and polygons.  Limited range of places where they can be used to maximum effect.

Advantages: lightweight, made from renewable materials, ideal where a 'natural' look is required.

Disadvantages: needs to be thoroughly waterproofed or lined to prevent leaks and distortion, available in a limited range of shapes, surface easily damaged by dents and scratches.

Concrete

Properties: very heavy but can be surprisingly stylish.  There is a limited range of shapes and styles available.  Increasingly popular in Scandinavia.

Advantages: custom-built containers relatively easy to make, can fit in well with modern interiors, strong and resistant to surface damage.

Disadvantages: very heavy and require careful manual handling when being moved, need to be lined or sealed to prevent a reaction between acidic growing media and the concrete, difficult to clean, difficult to reposition once set up.

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Author: Kenneth Freeman

Photography: David Cropp